JP4324066B2 - Design equipment for optoelectronic circuits - Google Patents

Description

The present invention relates to a design method, a design apparatus, a design program, and the like for a circuit (also referred to as a photoelectric fusion circuit) in which an electronic circuit connected by electrical wiring and an optical circuit by optical connection are mixed.

Recently, information processing devices such as personal computers, mobile phones, and personal information terminals (PDAs) have been demanded to be faster in processing in addition to being smaller and lighter, but as processing speed increases, Problems such as wiring delay and EMI (electromagnetic radiation interference noise) occur in the circuits used there. As a technique for avoiding these wiring delays and EMI, there is a method using an optical circuit using optical connection (see Patent Document 1).

On the other hand, in the control devices such as the information processing device and the robot described above, it is desired to control by switching a plurality of control algorithms in real time. From such a viewpoint, a circuit that can be reconfigured, particularly a circuit that can be reconfigured at high speed in real time is desired. Examples of reconfigurable circuits include Field Programmable Gate Array (FPGA) and Complex Programmable Logic Device (CPLD) (see Patent Document 2), but further improvements are possible in terms of high speed and circuit scale. It is desired.

In the design flow examples used to design these information processing devices (semiconductor systems), in general, after designing a system based on the required specifications, through logic design, generating a circuit connection list (net list), layout design (Place & route) and verification is performed (see FIG. 16). For example, there is a design method using this technique for a system having two chips (Patent Document 3). However, a design method for a system in which optical connections and electronic circuits are mixed is not known.
JP-A-6-308519 JP 2000-311156 JP 2001-298086

Therefore, in order to realize advanced information processing equipment and control equipment, it is necessary for the circuit to have a large scale, high speed, flexibility (reconfigurable), and such requirements. In order to satisfy the above, it is conceivable to use a circuit in which an optical circuit and an electronic circuit are mixed, that is, a photoelectric fusion circuit. Conventionally, in designing a system in which an optical circuit using an optical fiber or an optical waveguide is mixedly mounted with an electronic circuit, the optical circuit and the electronic circuit are clearly shown in FIG. 16 at the initial stage of the system design shown in FIG. Separate and independent design. However, in such a design method, the optical circuit and the electronic circuit are designed independently. In designing an optical circuit, an optical device, an optical transmission line, a transmission distance, and the like are designed so as to satisfy required optical connection specifications (transmission speed and bit error rate). Here, as the light quantity design, loss analysis of the optical transmission line, optical coupling analysis between the optical transmission line and the optical device, etc. are performed, and further, the transmission speed and bit error rate are estimated based on the result of this light quantity design. The

However, in such a design method, since the optical circuit and the electric circuit are designed independently, it is difficult to perform a design that fully utilizes the performance of both circuits (hardware). Furthermore, optimal design was possible for each of the optical circuit and the electronic circuit, but the performance of the total optimization as the photoelectric fusion circuit was insufficient. In addition, the total design as a photoelectric fusion circuit requires advanced knowledge of both circuits, and a great deal of time and cost. In particular, the design of the optical circuit sometimes becomes a problem in design time and design reliability.

In view of the above SL problems, designing apparatus for optoelectronic circuit of the present invention has a laminated structure having a plurality of semiconductor chips and the electric wiring layer and the optical connection layer, optical layer is a sheet-like optical transmission medium And a design device for an optoelectronic circuit having a plurality of optical ports that perform at least one of input and output of an optical signal to an optical transmission medium, from a net list that is a circuit connection list, a connection list that is responsible for optical connection. A first means for generating a certain optical net; and a second means for assigning the optical net to a first optical connection book having information relating to a set of optical ports capable of optical connection in advance and performing design evaluation The optical network is assigned to a second optical connection book having information relating to a set of optical ports that can be optically connected in advance and having a different optical port type from the first optical connection book, and design evaluation is performed. Third means and the second means Compare the design result by said third means and the design result by stage, and having a fourth means for selecting a suitable design results in the required specifications, the.

Further, in view of the above-described problems, the photoelectric design circuit automatic design apparatus of the present invention is an optical module comprising a plurality of optical ports and a sheet-like optical transmission medium having a function of performing at least one of optical signal input and output. And a design device for designing an optoelectronic integrated circuit having an electronic circuit, and at least a storage means for storing data (optical connection book) having information on a pair of optical ports capable of optical connection, and an optical module Design means for designing an optoelectronic circuit by applying the optical connection book stored in the storage means, means for comparing the design results designed by the design means by applying different optical module configurations, and evaluating the design results It is characterized by having. This is an application of the present invention, characterized in that an optical circuit is designed using an optical connection book, to an automatic design apparatus for a photoelectric fusion circuit.

Further, in view of the above problems, the photoelectric fusion reconstruction system of the present invention has a circuit in which a semiconductor chip can be reconfigured, and the optical connection between the semiconductor chips can be changed via the optical connection layer. A design device that executes a design method for a photoelectric fusion circuit, a reconfigurable photoelectric fusion circuit, and an input / output unit, and the photoelectric fusion circuit is designed in the design device based on information from the input / output unit. The result is implemented in a reconfigurable optoelectronic circuit. This is an application of the present invention, characterized in that an optical circuit is designed using an optical connection book, to a photoelectric fusion reconstruction system.

In view of the above problems, the photoelectric evaluation circuit design evaluation apparatus of the present invention is mounted on the photoelectric fusion circuit that can be reconfigured with the photoelectric fusion reconstruction system and the photoelectric fusion circuit design result. It has an evaluation means for evaluating the result of the design. This is an application of the present invention characterized in that an optical circuit is designed using an optical connection book to an optoelectronic circuit design evaluation apparatus.

In view of the above problems, an automatic design program according to the present invention includes an optical module including a plurality of optical ports having a function of performing input and output of an optical signal and a sheet-like optical transmission medium, and an electronic circuit. An optoelectronic fusion circuit design program for designing an optoelectronic circuit based on data (optical connection book) that contains at least information about a set of optical ports that can be optically connected; another optical connection The present invention is characterized in that a step of designing an optoelectronic circuit based on a book, comparing a plurality of design results, and evaluating a design result is executed by a computer. This is an application of the present invention characterized in that an optical circuit is designed using an optical connection book to an automatic design program for a photoelectric fusion circuit.

According to the design method and design apparatus of the present invention described above, since the optical connection book is used, it is possible to design a sufficiently satisfactory optical circuit or photoelectric fusion circuit efficiently in a relatively short time.

The design of the photoelectric fusion circuit or the optical circuit of the present invention is characterized in that the design is performed using an optical connection book. That is, in designing an optical circuit, a plurality of virtual optical module configurations (optical connection books A, B, C,...) Are prepared in advance as shown in FIG. To design the optical connection. Then, the respective design results 24A, 24B, 24C,... Are compared, and an optical connection book that outputs a preferable design result and a design result corresponding thereto are selected and used as a result.

Here, the optical connection book is a virtual optical module configuration in which the configuration and arrangement of optical devices and waveguides are predetermined. Virtual is to be prepared as information. This information is stored in the memory of the design apparatus, and the design is performed using this information. In FIG. 1, the optical connection design is performed in parallel for a plurality of optical connection books. However, in the design of the photoelectric fusion circuit or the optical circuit of the present invention, the selection (change) of the optical connection book as shown in FIG. A method of repeatedly performing optical connection design and optical connection analysis may be used.

In particular, a circuit in which an electronic circuit and an optical circuit are mixed can be expected to improve the performance, but on the other hand, the design tends to be difficult because of increasing diversity and complexity as compared with the design of only an electronic circuit. Designers also require advanced knowledge of both electronic and optical circuits.

Therefore, since the degree of freedom in designing optical modules is limited to some extent by using the above-described optical connection books, each optical connection book is highly reliable in a short time with a relatively small load. Optical circuit design can be performed. In particular, when applying an optical module with a high degree of freedom of connection, such as the optical free circuit described later, the degree of freedom of optical connection provides merit as hardware, but the design tends to be more difficult. It is a very effective technique. In addition, the degree of freedom is limited as a single unit of the optical connection book, but various variations of the optical connection book are prepared, each of them is designed, and a preferable one is selected, so that the final one is selected. The degree of freedom in design does not drop significantly.

Furthermore, it is possible to accumulate design assets for a system to which each optical connection book (an optical module whose configuration has been determined) is applied to various applications (specifications). This facilitates design reuse. Even when a design change occurs due to an increase in the specifications of an electronic circuit or an increase in the specifications of an optical module, the design load can be reduced by preferentially evaluating an optical connection book having a similar configuration. Furthermore, since the optical module corresponding to the optical connection book is commonly used for various specifications, it can be mass-produced. Thereby, the cost of the optical module can be reduced.

In other words, by using this optical connection book to design a circuit (photoelectric fusion circuit) in which an electronic circuit and an optical circuit are mixed, the design of a highly optimized photoelectric fusion circuit as a whole The present invention can be implemented at high speed and with high reliability (of course, the present invention can also be applied to an optical circuit having only an optical connection). This leads to a design that maximizes the hardware performance of the optoelectronic circuit, and the final optoelectronic circuit can have excellent cost performance.

Next, after describing typical hardware (photoelectric fusion substrate) targeted by the method for designing an optoelectronic circuit according to the present invention, a design method serving as the basis of one embodiment of the present invention will be described.

<Hardware targeted by the design method>
First, typical hardware used in the present invention, that is, a photoelectric fusion circuit will be described with reference to FIG. In FIG. 6, reference numeral 100 denotes a substrate, 101 denotes a two-dimensional optical transmission medium, 102 denotes an optical port that performs at least one of light output and input, 103 denotes propagating light that propagates through the optical transmission medium 101, 105 denotes an electrical wiring layer, 106 Is an electrical wiring, and 107 is an electronic device. 6A is a plan view showing the arrangement of the electronic device 107, and FIG. 6B is a cross-sectional view of the photoelectric fusion substrate.

6B, an electronic module having an electronic device (semiconductor chip) 107 and an electric wiring layer 105, an optical module having an optical transmission medium 101 and an optical port 102 (optical connection layer) are stacked, It is bonded and is compactly mounted with a layer structure. In other words, an electronic device (semiconductor chip) 107 is mounted, and a photoelectric fusion substrate in which they are interconnected by electrical wiring and optical connection.

FIG. 6B is a sectional view of a circuit having three chips 107a to 107c and optical ports 102a to 102c. As shown in FIG. The port can be placed at any position. In addition, the optical port 102 is arranged at the upper part in contact with the optical transmission medium 101, but is not limited to this, and is arranged so as to be embedded in the optical transmission medium 101, and directly couples light to the waveguide 101. Or may be disposed on the end face of the optical transmission medium 101. Also, the number of layers of the optical transmission medium 101 can be any number.

The optical port 102 is a component having a function of transmitting or receiving an optical signal as described above. That is, it has an optical output unit that converts an electrical signal into an optical signal, an optical input unit that converts an optical signal into an electrical signal, or both. The light emitted from the light emitting element that is the light output unit of the optical port responsible for transmission propagates through the optical transmission medium 101 and is input to the light receiving element that is the light input part of the optical port responsible for reception. By converting the signal into an electrical signal at the optical port responsible for reception, signal transmission from the optical port 102 to the optical port 102 is performed, and an optical circuit is configured. In this way, the signal from the electronic device 107 is converted into an optical signal in the optical port 102, the optical signal is propagated through the optical transmission medium 101, converted into an electrical signal in another optical port 102, and input to another electronic device 107. Is done. In addition, the electronic devices 107 that are closer to the electric wiring layer 105 are connected by electric wiring. In this way, the electronic devices 107 can be optically connected in addition to being connected by electrical wiring.

As already described, as the optical transmission medium 101, a two-dimensional waveguide (sheet-shaped optical waveguide) is typically used. In this specification, the optical free circuit is such a two-dimensional waveguide, and an optical device can be arranged at an arbitrary position if it is desired to be performed. Optical data is transmitted two-dimensionally to the port. For example, as shown in FIG. 13, the propagation light 103 from the optical port 102 can be transmitted in any set propagation direction and emission angles 104a and 104b to select a transmission destination. Here, although the setting range of the radiation angle 104 is not particularly limited, for example, it can be broadcast in all directions of 360 °, or can be transmitted in a beam shape with a radiation angle as small as possible corresponding to the radiation angle of the light emitting element. The circuit can be changed with a high degree of freedom by controlling the light propagation direction and the radiation angle.

With respect to the connection combination of one-to-one optical ports, the optical free circuit can be bidirectionally communicated in an arbitrary set and can be a circuit that can be completely coupled. Furthermore, it is possible to realize 1: N multicast communication and N: M communication, and it is a circuit with a high degree of connection freedom. Furthermore, the optical free circuit can be switched and reconfigured as described above. That is, it is possible to switch (reconfigure) a combination between one-to-one optical ports, and further switch a transmission path between a plurality of optical ports, that is, switch (reconfigure) 1: N or N: M transmission. ) Is possible.

In this way, an optical free circuit using a two-dimensional waveguide can be completely coupled between optical ports, and is a reconfigurable circuit having a high degree of connection freedom capable of multicasting. Interconnecting possible electronic circuits is a preferred means in building highly reconfigurable systems.

As the optical transmission medium 101, any material such as glass, a semiconductor, and an organic material can be applied as long as it has a sufficient transmittance with respect to the propagating light 103. For example, a commercially available glass substrate, a single crystal substrate such as lithium niobate, a semiconductor substrate such as Si or GaAs, an organic sheet made of polycarbonate, acrylic, polyimide, polyethylene terephthalate, or the like can be used as it is. Alternatively, a method of forming a film by any method such as vacuum deposition, dipping, coating, a method of forming by injection molding, extrusion molding, or the like may be used. The clad layer may be formed by coating the surface with layers having different refractive indexes. Since the size of the optical transmission medium 101 transmits information between two-dimensional arbitrary positions, depending on the information transmission speed, the size can be, for example, about 100 microns to several tens of centimeters. The thickness of the optical transmission medium 101 can be in the range of about 1 micron to several centimeters, but a thickness of about 50 microns to several millimeters is preferable from the viewpoint of easy alignment of the optical axis.

The propagating light 103 is propagated at an appropriate radiation angle in the plane of the two-dimensional optical waveguide 101. However, in the direction perpendicular to the plane, all propagating angles (all waveguide modes) are propagated or selected. It is possible to propagate a specified angle (single propagation mode), but not particularly.

Examples of the light emitting element applicable to the light output unit of the optical port 102 include a laser diode and an LED. Among these, a surface emitting laser having a small light emission angle is preferable from the viewpoint of realizing a propagation light having a small emission angle. The light output unit of the optical port 102 can have means for switching the radiation angle and the emission direction. Thus, in the two-dimensional optical waveguide 101, light can be propagated from the optical port 102 at different radiation angles and directions, and these can be switched. As a means for switching the emission angle and direction, for example, a plurality of light output units capable of emitting light at different emission angles and directions are arranged in the optical port 102, and the light output unit used for transmission is electrically selected. There is a method of switching the radiation angle and direction of propagation. For example, a plurality of light emitting elements arranged in an array is used, and different emission angles and emission directions are set and sorted for each element of the array. In this case, by selecting a light emitting element to be used in the array, the emission angle and the emission direction can be set and sorted.

Furthermore, as a light emitting element applied to the light output unit, a device that can control and change the emission angle and the emission direction can be used. There is also a method of changing the emission angle and the emission direction by making the coupling mode of the light emitting element applied to the light output unit and the two-dimensional optical waveguide 101 variable. More specifically, the optical coupling unit such as a mirror, a prism, a lens, or a grating disposed in the vicinity of the light emitting element is moved, or the same effect is obtained by moving the position of the light emitting element itself. The optical properties such as the refractive index of the material constituting the material are modulated. As a means for moving the optical coupling portion, there is a method of forming a minute movable mirror or the like by applying an electrostatic force element, a magnetic element, a piezoelectric element, or the like by, for example, a technique of micromechanics.

In this way, the optical port 102 is configured to be able to propagate at various radiation angles and radiation directions as the radiation angle 104, as shown in FIG. In order to realize this, various configurations can be used as the optical coupler. An example of the optical coupler 301 is a quadrangular pyramid mirror as shown in FIG. Light 303 from the light emitting element 306 is irradiated from above the pyramid mirror, reflected in the lateral direction, and coupled to the optical transmission medium. As shown in FIG. 14B, when light from the light emitting element is irradiated onto one inclined surface (light irradiation position 302) of the pyramid, propagation at an emission angle of approximately 90 ° is realized, and FIG. When the four slopes are irradiated as in (), propagation is performed with a 360 ° radiation angle. For 2 and 3 slopes, they are 180 ° and 270 °, respectively. Since the pyramid slope is a diffusing surface, uniform light is propagated over a range of radiation angles.

In the example of FIG. 14, for example, a total of five light emitting elements 306a, 306b, 306c, 306d, and 306x are arranged above the pyramid mirror 301, one for each slope and one for the center. Are arranged so that each slope is irradiated. With such a configuration, the emission angle can be set by selecting a light emitting element. For example, if the central light emitting element 306x is used, if one of 306a to d is selected in all directions of 360 °, the direction of 90 ° is determined if two are selected, and the direction of 180 ° is selected if two are selected. If one is selected, it can be propagated in the 270 ° direction, and if four is selected, it can be propagated in the 360 ° direction. In this manner, by arranging a plurality of light emitting elements in the optical port 102 and selecting the light emitting element to be driven, the radiation angle and the radiation direction can be switched.

Here, an example of an optical port that uses a pyramid mirror and can select a radiation angle and a radiation direction in units of 90 degrees is not limited thereto. Even if an optical port that can broadcast in almost all 360 ° directions, can realize beam-like propagation with a radiation angle as small as possible corresponding to the radiation angle of the light emitting element, and can also propagate in various directions, etc. Good.

An optical signal propagating through the optical transmission medium 101 is taken into the light receiving element of the optical port 102 and converted into an electronic signal. As the light receiving element, a PIN type or MSM type photodiode can be used, and this photodiode is connected to an electronic circuit, and the converted electric signal is taken into an adjacent electronic circuit as an input electric signal and processed. The

The optical input unit of the optical port 102 can take various configurations. For example, the two-dimensional optical waveguide 101 can be configured to receive light from all directions over 360 °. Alternatively, it may be configured to receive only light from a predetermined direction of the two-dimensional optical waveguide. An optical coupler can also be applied to the optical input section. From the above viewpoint, a conical or spherical mirror is used as an optical coupler applied to the optical input unit in order to receive light from an arbitrary direction, that is, an in-plane 360 degree direction. Further, as the optical port 102, a plurality of light receiving units arranged in an array can be used. In particular, the light receiving section can be arranged so that the incident directions to the respective elements of the array are different. In this case, by selecting the light receiving unit used in the array, it is possible to sort the direction in which the light has arrived. As an example of such a configuration, there is a configuration in which a pyramid-shaped optical coupling unit is used and a light receiving unit is arranged corresponding to each surface.

Here, the reason why the two-dimensional optical waveguide is preferable in the optical transmission medium of the present invention will be described. First, an optical circuit using an optical fiber or a line waveguide may be used. However, since the line wiring is fixed, the degree of freedom of wiring is inferior. Realizing the reconfiguration of the optical circuit with this configuration involves difficulties such as the need for many optical switches. Furthermore, the linear optical waveguide needs to be aligned with the optical axis in a size of several microns to several tens of microns, which is difficult. In addition, it is difficult to fabricate the optical waveguide because it requires fine processing.

On the other hand, by applying a two-dimensional waveguide, an optical device (light emitting element or light receiving element) can be mounted at a desired arbitrary position, and information can be transmitted between arbitrary positions. Furthermore, optical alignment is facilitated in optical coupling between the optical device and the waveguide layer. Because of such a simple configuration, a circuit board can be easily formed, and the cost can be reduced. Furthermore, as will be described later, in an optical free circuit to which a two-dimensional optical waveguide is applied, an optical circuit can be reconfigured basically only by controlling an optical port that is an optical input / output unit.

On the other hand, since the line waveguide is capable of high-speed signal transmission, it may be embedded in a two-dimensional optical waveguide to carry a predetermined fixed connection. As an optical transmission medium, a method of propagating light in free space has been proposed. However, this method has a problem that the wiring size is high but the size becomes large. A configuration using an optical free circuit using a two-dimensional optical waveguide can realize a thin and high-density circuit board.

The optical transmission medium 101 can be disposed on an arbitrary substrate 100. As the substrate 100, a printed substrate, a metal substrate such as aluminum or SUS, a semiconductor substrate such as Si or GaAs, an insulating substrate such as glass, or a resinous substrate or sheet such as PMMA, polyimide, or polycarbonate can be applied. The electrical wiring 106 is a metal wiring such as aluminum or copper, and for the production thereof, a vacuum deposition method or a method of forming a conductive paste by a screen printing method is used. In addition, a method of forming a circuit conductor pattern by stacking metal foil such as electrolytic copper foil and chemically etching the metal foil using an etching resist formed in a desired pattern is used. In FIG. 6, the layers of the optical transmission medium 101 are shown as a single layer, but a plurality of layers may be provided.

<Optical circuit design method>
Next, an optical circuit design method according to this embodiment will be described. The hardware configuration of the optical module assumes an optical module to which a two-dimensional optical waveguide is applied as the above-described optical transmission medium.

First, as described above, as shown in FIG. 1, a plurality of virtual optical module configurations (optical connection books A, B, C,...) Are prepared in advance, and each of these optical connection books is prepared. Do optical connection design. Each of the design results 24A, 24B, 24C,... Is compared, and an optical connection book that outputs a preferable design result and a design result corresponding thereto are selected and used as a result.

The optical connection book is information relating to a virtual optical module configuration in which the configuration and arrangement of optical devices and waveguides are predetermined. This information is stored in the memory of the design apparatus, and design is performed using this information. The optical connection book has at least a combination of optical ports capable of transmitting information as information. As shown in FIG. 10B, the configuration of the optical transmission medium, such as size, material, propagation loss, etc., and further, the configuration of the number of optical ports in the optical module, the arrangement of optical ports, the types of optical ports, etc. You may have the above information. Furthermore, it has useful information in terms of design, such as a transmission speed that can be transmitted between the respective optical ports and a combination of optical ports that can be transmitted simultaneously (information on crosstalk).

In particular, with respect to the arrangement of the optical ports 102, as shown in FIG. 3, information on the in-plane position and further the thickness position (in-layer position) in the stacked structure in FIG. 6B can be specified. . Regarding the latter, the optical port 102 is arranged at the interface between the optical transmission medium 101 and the electric wiring layer 105 in FIG. 6B, but on the semiconductor chip 107 or between the semiconductor chip 107 and the electric wiring layer 105, It can be set at an arbitrary position such as on the electric wiring layer 105 or inside the electric wiring layer 105.

As an example, FIG. 3 illustrates three types of optical connection books. In FIG. 3, the optical connection book is shown as a figure, but in the design apparatus, this is expressed as character information (data) and stored in the memory. However, when the design apparatus has a display device or an image output device, such a drawing can be displayed instead of the data information. This is preferable because it assists the designer to grasp the configuration of the optical connection book. Hereinafter, a configuration example of the optical connection book will be described with reference to the drawings.

FIG. 3 is a plan view showing the arrangement and types of the optical ports 102 in the optical module. In the figure, the optical ports 102 are symbolized according to the types. Different symbol optical ports 102 have different configurations. The types of optical ports and the symbols on the notation are shown in FIGS. Various types can be applied.

In FIG. 3, each optical port has a reception function in addition to a transmission function. However, in order to simplify the drawing, the description of the type of optical port on the reception side is omitted. Actually, except for the optical port connected to the line waveguide, all others have a reception function, and the reception function is the omnidirectional reception type of FIG.

The optical connection book A shown in FIG. 3 uses a two-dimensional optical waveguide as an optical transmission medium, and nine optical ports 102 are arranged. The optical connection book B uses a two-dimensional optical waveguide as an optical transmission medium, and eight optical ports 102 are arranged. The optical connection book C mainly includes a two-dimensional optical waveguide as an optical transmission medium, and partly has a line waveguide. Since there are optical ports at both ends of the unidirectional line waveguide, the number of optical ports 102 is thirteen. In this manner, a plurality of virtual optical module configurations (optical connection books) having different optical transmission medium configurations, optical port positions, optical port types, and optical port numbers are prepared.

FIG. 4 shows a configuration example of an optical port that transmits an optical signal, and FIG. 5 shows a configuration example of an optical port that receives an optical signal. FIG. 4A shows an optical port that diffuses light in all directions of 360 ° of the two-dimensional optical waveguide. In FIG. 4B, the area diffusion is indicated by a predetermined angle (in the circle on the notation). The light is diffused and propagated in the gray direction). Here, examples with radiation angles of 90 ° and 180 ° are shown. The radiation angle, the radiation direction, and the like are not limited to this, and arbitrary ones can be set. FIG. 4C shows an optical port that propagates in the form of a beam without diffusing the light emission angle of the light emitting element from the optical port as much as possible. In the notation, an optical signal is propagated in a specific direction indicated by an arrow. Depending on the configuration of the optical port, the beam can be propagated in multiple directions simultaneously.

FIG. 4D shows an optical port capable of propagating the beam in an arbitrary set direction as a variable beam. Further, as shown in FIG. 4E, a plurality of light emitting units that propagate an optical signal in a specific direction indicated by an arrow may be arranged in the optical port to have a plurality of functions. A desired function can be operated by selecting a light emitting unit to be driven.

FIG. 5 (a) shows what receives optical signals from all directions (all directions of 360 degrees) propagating through the optical transmission medium, and FIG. 5 (b) shows a predetermined angle (in the circle on the notation). FIG. 5 (c) shows a signal receiving signal with variable reception direction or angle range. FIG. 5D shows an example of an optical port having a plurality of transmission functions and reception functions. This is an example having two beam propagation outputs to the two-dimensional optical waveguide, input (reception) from all directions, output to the line waveguide, and input function from the line waveguide. FIG. 5 (e) shows symbols for the case where a line waveguide is provided in an optical transmission medium and optical transmission is performed using the line waveguide. The start point of the arrow corresponds to the optical port on the transmission side, and the end point corresponds to the optical port on the reception side. The notation on the drawing is not limited to this. If the type of optical port can be discriminated, it is not particularly concerned.

It is preferable that the optical connection book has a list of transmission rates and transmission delays that can be transmitted between the optical ports in advance. By designing using this list, the reliability of optical connection is ensured, so that a highly reliable design as a photoelectric fusion substrate can be performed. To create this list, from the physical configuration information such as optical port configuration, optical port position, optical transmission medium, etc., analyze the amount of light used for each optical connection, the distance between optical ports, etc. From these, the transmission rate and delay time can be obtained. In addition, an optical module corresponding to the optical connection book may be made as a prototype, and an actual evaluation may be performed to obtain a transmission rate and a delay time and make a list.

Here, the optical connection book has been described in which the type of optical port and the position of the optical port are specified. However, only the position of the optical port is specified, and the type of optical port can be freely selected in the later design process. May be. In that case, it is possible to list the types of optical ports as an optical port book and select and use the optical ports at the time of design.

In order to realize such a design method, it is preferable to prepare an optical connection library and an optical port library as a device that stores a large number of the above-described optical connection books and optical port books (information on optical ports) in the design apparatus. . In the design method of the present invention, an appropriate optical connection book and optical port are selected from the optical connection library or optical port library.

<Guidelines for optical connection book>
The optical connection book is not limited to the one described above, but can be prepared in various configurations. However, it is more preferable to prepare an optical connection book based on the following guidelines. First, it is preferable that the positions of the optical ports are dispersed as much as possible. The reason is that there is a high possibility that the electrical wiring is congested near the optical port that can be connected with a high degree of freedom. With such an arrangement, many electric nets can be effectively connected to the optical port, so that various designs can be made for the electronic circuit (various designs are possible and the design range is widened). Furthermore, the optical module contributes to efficient use of the optical transmission medium and reduction of crosstalk. That is, such an arrangement works effectively for both electronic and optical circuits and enhances the performance of the final optoelectronic circuit.

In addition, it is preferable to arrange the optical port so that a connection form having a large load (difficult) for the electrical wiring can be realized by the optical connection. Such an arrangement of the optical ports enables a total optimum design as a photoelectric fusion circuit. For example, it is common to use only the x and y directions as electrical wiring. In such a case, it is preferable to intentionally arrange an optical port so that an optical connection close to an oblique direction is made.

In addition, from the viewpoint of a connection form that is difficult for the electric wiring, it is preferable to arrange the optical ports as far as possible in view of the fact that it is difficult for the electric wiring to transmit a high-speed signal over a long distance. From the same point of view, since electrical wiring consumes a great deal of wiring resources for multicast and matrix connection, it is preferable to arrange optical ports so that broadcast connection is possible. In this way, by arranging the optical ports so as to be realized by optical connection by selecting a connection form that is difficult with electrical wiring, not the optimal design only for the optical module but the optimal design for the entire optoelectronic circuit is realized.

In the following, a method for designing an optoelectronic circuit according to the present invention will be described with reference to more specific examples. However, the present invention is not limited to the embodiments described below, and can be added, omitted, and the like as long as it is included in the above concept.

"Example 1"
First, hardware applied to the present embodiment will be described. In this embodiment, hardware of the type shown in FIG. 11 was used. In FIG. 11, 101 is an optical transmission medium, 102 is an optical port, 106 is an electrical wiring, and 107 is a semiconductor chip. 107A, 107B, 107C, and 107D are custom chips, and 107E is an FPGA. FIG. 11A is a top view, FIG. 11B is a top view of the optical transmission medium 101, and the cross-sectional view thereof is in accordance with FIG. 6B.

The main design constraints on the hardware are that the number of electrical wiring layers is 8, the size of the optical transmission medium is 3 cm □, the number of optical connection layers is 1, and the number of optical ports is 10. The optical connection layer is based on an optical free circuit using a two-dimensional optical waveguide as an optical transmission medium. The optical transmission medium has a structure of a two-dimensional optical waveguide, which is a 100 μm thick polycarbonate (refractive index: 1.59) coated with fluorinated polyimide (refractive index of about 1.52) as a clad. Also, in the optical connection book, it is allowed as a design constraint to embed a line waveguide in a part of a two-dimensional optical waveguide.

Next, a method for designing the photoelectric fusion circuit of this embodiment will be described. FIG. 7 shows an outline of the design flow of the photoelectric fusion circuit of this embodiment. After performing a schematic system design 21 based on the required specification 20, a circuit connection list (net list) 10 is generated through a logic design 22 and a circuit design, and an optoelectronic design 11 is performed based on this.

In the photoelectric fusion design 11, an electronic circuit layout design 15 and an optical circuit design 17 are made through generation 12 of an electric net and an optical net. In the optical circuit design 17 of the present embodiment, the optical circuit design shown in FIG. 1 is applied. Further, the application targeted in the design of this embodiment is the content obtained by adding an image processing function to the video signal decoder.

Hereinafter, each process will be described. First, in the system design 21, in view of the required specification 20, a schematic system configuration is determined. The required specification 20 includes functions to be realized, that is, functional specifications and design constraints. The functional specification is a function to be satisfied by the circuit, and is set variously depending on the application, such as an arbitrary control algorithm, image processing, and audio processing. On the other hand, design constraints include performance, power consumption, cost, design period, and the like. Based on these considerations, the system design 21 determines the division of hardware and software and the outline of the hardware configuration. Examples of the hardware configuration include the number and types of semiconductor chips, the number of layers of the electrical wiring board, the area, the quantity, the configuration of the optical module (list of optical connection books), and the like. However, some of these hardware configurations may be restricted as design constraints.

In the conventional general design, as shown in FIG. 16, the optical circuit and the electronic circuit were separated at the system design stage, and after that, independent design was performed, but in the system design of this embodiment, Does not divide the electronic circuit and the optical connection.

Next, logic design 22 is performed to obtain a circuit connection list (net list) 10. The netlist is data describing circuit connection information. In the present embodiment, the means for obtaining the netlist 10 is not particularly limited, and any logic synthesis tool or other means can be used. For example, a hardware description language (hardware
It is described in RTL (register transfer level) using description language), and logic synthesis is performed using a logic synthesis tool to obtain a gate level netlist. At this stage, logic verification simulation can be performed to increase the reliability of the design.

Alternatively, a netlist may be created by performing behavioral synthesis from a description in C language. In addition, logic design can be performed using an arbitrary IP (intellectual property) macro such as a processor, a memory, an interface, data compression, and image processing. As the netlist, any connection information such as a transistor level, a gate level, a cell level, a functional block (cell set) level, an IP macro level, or the like can be applied. Furthermore, in the case of a design having an analog circuit, the circuit design of the analog part is finished at this stage and used as a macro, so that the net list creation process can be advanced.

Subsequently, photoelectric fusion design 11 is performed based on the net list, and a design result (output information) 24 is obtained. A method of the photoelectric fusion design 11 of this embodiment will be described. Here, the design was performed using the optoelectronic circuit design apparatus shown in FIG. This optoelectronic circuit design device has input / output means, storage means 81, design means 82, design evaluation means 83, and control means 84. The storage means 81 includes an optical connection library (a plurality of optical connection books), a netlist, an electric net, an optical net, various design parameters, design results, intermediate design results, design time, functional specifications and design constraints as required specifications, etc. It is a part for memorizing.

The input / output means is a means for allowing the above-described data to be input from the outside and outputting design results, evaluation results, and the like to the outside. The design means 82 includes means for generating the electrical net 13 and the optical net 14 from the net list 10, optical port placement means, electronic circuit layout design means (including placement means and wiring means), optical connection design means, and verification means. Have. Furthermore, it has the control means 84 which controls the whole of these design means. In the present embodiment, the design means 82 and the control means 84 are implemented as programs (software) in a general computing device.

In optoelectronic design 11, first, the connection list (electric network)
13) and a connection list (optical network 14) that the optical connection bears are generated (in this embodiment, the optical connection book is not yet used at this stage). Thereafter, verification of the generation of the electric net and the optical net may be performed. For example, it is possible to verify whether the contents of the net list before the division and the combination of the electric net 13 and the optical net 14 are logically coincident.

Further, when the electric net and the optical net are generated, electronic circuits (electric nets) such as registers, flip-flops, serializers, and deserializers may be newly added around the optical circuit if necessary. At this time, these additional contents are added to the electric net. For example, when the parallel electrical wiring portion is assigned to the optical connection, a serializer may be added to the transmission side optical port, and a deserializer may be added to the reception side optical port.

Next, photoelectric fusion layout design based on electrical net 13 and optical net 14
Do 15. In this process, design such as arrangement of various parts, connection of electric wiring, optical connection, and the like is performed. Here, the component refers to a cell in a standard cell LSI, a functional block having one function in a set of cells, a block corresponding to an IP macro, and the like. In systems to which FPGAs are applied, logic cells, configurable blocks, blocks corresponding to IP macros, and the like also correspond to this. Furthermore, in the case of a system in which a plurality of chips are mounted, a single chip or device is also included in the component. In other words, in the photoelectric fusion circuit mounting a plurality of chips, in this process, chip arrangement, wiring between chips, allocation to an optical port of an optical net, cell arrangement in a chip, electric wiring in a chip, etc. This is a design step. In this embodiment, the optical connection book is selected in this step.

In the present embodiment, an electronic circuit layout design 18 based on the electric net 13 and an optical circuit design 17 based on the optical net 14 (here, the optical circuit design is also included because the optical connection book selection process is included. In the case where the selected optical connection book is assumed, the order of the optical connection design) is not concerned. They may be performed in order (whichever is first) or may be performed in parallel. However, both are performed independently.

As the electronic circuit layout design 18, component placement, wiring, and electronic circuit analysis are performed. A general technique can be applied as the placement and wiring of the electronic circuit. For example, the min-cut method (min-cut method)
placement) or the like. Wiring includes line search router, maze-running router, channel wiring method (channel
router) or the like. In addition, the wiring can be divided into a schematic wiring for assigning each net to a channel set in the wiring area and a detailed wiring for determining a wiring path in each channel. As the electronic circuit analysis, a delay value of a signal in each net is calculated from the wiring resistance and wiring capacitance of the wiring itself, and timing analysis is performed based on the delay value. In addition, EMI analysis such as crosstalk and waveform distortion may be performed.

In the optical circuit design 17, the design method shown in FIG. 1 was used. That is, the optical circuit of this embodiment is designed using a plurality of optical connection books (optical module configurations) A, B, C,... Prepared in advance as shown in FIG. I do. In the present embodiment, four types of optical connection books are prepared in advance in view of the optical network (particularly the number of required optical connections). Here, an optical connection book having 12 optical ports was prepared. In the four types of optical connection books, the number and position of optical ports are the same, but the types of optical ports at the respective positions are different. For optical connections between optical ports, possible combinations of optical connections, data transmission speed of optical connections, information on crosstalk, etc. are analyzed in advance and listed in the optical connection book.

Subsequently, for each optical connection book, an optical net is assigned to the optical connection described in the optical connection book. Each of the design results 24A, 24B, 24C,... Is compared, and the optical connection book that satisfies the required optical connection and outputs the design result 24 with the largest margin among them, and the design result corresponding thereto are adopted as a result. . At this time, since the optical connection book has information relating to transmission speed and crosstalk in advance as a list in connection between optical ports, it is possible to determine whether or not optical connection is possible and a connection margin in a short time.

Next, in verification 19, it is verified whether the design result of the photoelectric fusion circuit as a whole satisfies the required specifications (function, circuit speed, circuit area, power consumption, etc.). Verification can be performed by performing various simulations. In particular, in the circuit timing verification, it is preferable to perform analysis in consideration of both the delay analysis of the electric net and the delay analysis of the optical net. Design results through as this factory will be the final design result 24.

In this embodiment, the mask is raised based on the design result 24 obtained by the above design, and the ASIC, the optical connection layer, and the electric wiring layer are created. Then, the optical connection layer 101 and the electrical connection layer 105 are bonded together, and the chip 107 is mounted to obtain a configuration similar to that shown in FIG. Furthermore, the designed optoelectronic circuit was realized by building a circuit inside the FPGA using the design results.

FIG. 11 is a diagram showing an example of the design result of the present embodiment. A to E are semiconductor chips 107. In this embodiment, A, B, C, and D are custom chips, and E is an FPGA. FIG. 11A shows the arrangement of the chip 107 together with the main electric wiring 106 of the uppermost layer. FIG. 11B is a diagram in which the type and position of the optical port 102 and the arrangement of the chip 107 are superimposed on the optical connection layer 101. In the figure, the notation of FIGS. 4 and 5 is used for the optical port 102. As a main optical connection, a line waveguide 108 is applied to a connection connecting DA and AB, and a broadcast optical connection using a two-dimensional optical waveguide 101 is used for connection from E to another chip. . The electrical wiring and optical connection described here are only a part of them in order to explain typical optical connection examples.

The above-described design method of the photoelectric fusion circuit of this embodiment has the following merits.
By using the optical connection book, the optical circuit can be optimized and designed in a relatively short time with high reliability. Since the design of the optical circuit is easy, even an electronic circuit engineer who does not have deep knowledge about the optical circuit can easily design the optoelectronic circuit. Further, the use of the optical connection book as a design asset makes it easy to reuse the design asset.

Compared to the conventional design method, that is, the method of FIG. 16 in which the electronic circuit and the optical circuit are separated in the initial system design, the design method and the design apparatus of the present embodiment generate the netlist 10 (that is, logical design). Later, the optoelectronic circuit is designed. In this embodiment, the optical connection and the electrical wiring are assigned after the step of generating the circuit connection list (net list 10). By using such a design method, there are the following effects.

First, when a failure is found in the design result in the verification process, it is necessary to make design changes retroactively to the most upstream system design in the conventional method. Need to consider the possibility of redesign). On the other hand, in the method of the present embodiment, it is sufficient to perform redesign only in the steps after the netlist generation. This reduces the redesign load and leads to a reduction in development time.

Further, since the generation of the netlist 10 does not depend on the design constraints related to the optical circuit, it is easy to reuse the netlist that is an intellectual asset. A netlist created to implement a system with only electronic circuits can be used as it is. Furthermore, it is not necessary to make major changes to the logical design when changing the hardware specifications including the optical module. For example, when the specifications of an optical module are improved, optimization and performance improvement as a photoelectric fusion circuit can be achieved without greatly changing the logic design.

"Example 2"
Next, Example 2 will be described. For Example 2, only the parts different from Example 1 are described. FIG. 8 shows an outline of the design flow of the photoelectric fusion circuit of the second embodiment. As shown in the figure, in this embodiment, unlike the first embodiment, the optical connection book selection process is executed at a relatively early stage, and the design of the photoelectric fusion circuit 11 is performed for the selected plurality of optical connection books. (In Example 1, optical circuit design 17 was performed for a plurality of optical connection books). Therefore, the electronic circuit design and the optical circuit design based on the respective optical connection books are made. That is, the design results of a plurality of electronic circuits and optical circuits are output as many as the number of optical connection books, and a preferable result is selected from them.

In this embodiment, 10 types of optical connection books were prepared in advance. The number of optical ports of each optical connection book is 10 to 20, and the types and arrangements are various. In step 12 of generating the electric net and the optical net, the electric net 13 and the optical net 14 are generated from the net list 10 based on the respective optical connection books. In the optical connection book, since the number of optical ports mounted on the optical module is determined in advance, this limits the number of nets that can be handled by the optical net. Based on this, one to be assigned to the optical net is selected from the net list 10. At this time, it is preferable to apply a design that maximizes the performance of the optical module.

In this step, a plurality of netlists can be assigned to one optical connection (optical net). For example, a plurality of parallel connections can be assigned to a one-to-one serial optical connection. At this time, since the optical connection is capable of high-speed signal transmission, information corresponding to a plurality of wirings can be transmitted in a time division manner. In addition, when an optical free circuit is applied to the optical module, a plurality of fan-out signals may be assigned to the broadcast optical connection. Here, the optical free circuit is a circuit that can be optically connected to each other over any combination of optical ports as described above.

Since a plurality of netlists can be assigned to a smaller number of optical nets in this way, the number of nets that can be handled by the optical net is not uniquely determined. In other words, the number of electrical nets can vary depending on the configuration of the optical module and the way of allocation to the optical net. In particular, in a system to which an optical free circuit is applied, the diversity of optical connections is high, and allocation to various optical networks can be considered. For example, considering the case where the number of optical ports is determined in advance, the number of nets that can be handled with only 1: 1 optical connection is limited to half of the number of optical ports, but more in optical free circuits. Can be treated as an optical net.

In this step, it is preferable that the number of electric nets be reduced as much as possible in order to take advantage of the characteristics of the optical free circuit. In an actual design, there is a method of generating a plurality of pairs of optical nets and electric nets, calculating the number of electric nets for each, and selecting the one that minimizes this. More specifically, high-Fan-out, high-Fan-in parts and parallel connection parts in the net list are preferentially assigned to the optical net. High fan-out electrical connections increase the driver load and disrupt the electrical signal waveform. Making such a connection as an optical connection is a preferable choice from the viewpoint of EMI of electric wiring in addition to reducing the number of electric nets.

In addition, in order to take advantage of the characteristic of optical connection that high-speed data transmission is possible, it is also a preferable example that the parallel wiring is positively assigned to the optical net and handled as a serial optical connection. Furthermore, when a net for transmitting a high-speed signal is known in advance, it can be assigned to an optical net. In particular, since high-speed parallel electrical wiring tends to cause crosstalk, it can be said that realizing this by optical connection is a preferable choice from the viewpoint of EMI.

Based on these considerations, allocating the part where the parallel connection is fan-out to the optical network is one example that can make the most of the characteristics of the optical free circuit. Here, as a preferred example, the method of generating the electric net and the optical net so as to reduce the number of electric nets as much as possible has been described in detail, but this step may be performed based on other arbitrary guidelines. For example, the total electrical wiring length may be shortened, the power consumption may be decreased, or the circuit area may be decreased. It can be arbitrarily selected based on the functional specifications that are ultimately aimed at.

In the present embodiment, the electronic circuit layout design 18 of FIG. 8B is in accordance with the first embodiment. However, the total electrical wiring length and the like are calculated from the result of the electronic circuit layout design. In the optical connection design, an optical net is assigned to the optical connection for each optical connection book. Here, the allocation is performed so that the connection margin of the optical connection is increased.

Subsequently, a preferable result is selected from design results for a plurality of optical connection books. In particular, in the present example, the short total electrical wiring length was selected from the design results of the system to which a plurality of light sheet layouts were applied. The short total electrical wiring length indicates that the optical module, particularly the optical free circuit, is functioning effectively. Here, as an example of a preferable photoelectric fusion layout, a method of preferentially arranging optical ports so as to shorten the total electrical wiring length is used. However, this step may be performed based on other arbitrary guidelines. .

In the present embodiment, as described above, generating the electric net and the optical net so that the number of electric nets is as small as possible leads to the following effects. First, wiring (net) that tends to become a bottleneck in an electronic circuit and wiring that greatly restricts other electrical wiring can be preferentially assigned to an optical net. As a result, the load on the subsequent electronic circuit layout design 18 can be reduced. Furthermore, it is possible to output a design that fully utilizes the configuration of each optical module (optical connection book). By these, the design of the final optoelectronic circuit and the final form of the hardware can be improved.

In this embodiment, the optical connection book is selected so that the total electrical wiring length is shortened. As a result, not only the optimal design of the optical circuit and the electronic circuit, respectively, but also the optoelectronic integrated circuit was optimized as a whole. Furthermore, a photoelectric fusion circuit having good performance as a total of the photoelectric fusion circuit can be designed with high reliability. The optoelectronic circuit of this embodiment designed in this way is designed to take full advantage of hardware constraints and has high cost performance.

The design method of the present embodiment is a particularly effective method when designing a photoelectric fusion circuit having an optical circuit and an electronic circuit having a high degree of freedom of connection such as an optical free circuit.

"Example 3"
A third embodiment will be described. In the third embodiment, a reconfigurable photoelectric fusion circuit is used as hardware, and the photoelectric fusion circuit design method of the above-described embodiment is applied to the automatic design of this circuit.

First, hardware to be designed in this embodiment, that is, a reconfigurable optoelectronic circuit will be described with reference to FIG. As a photoelectric reconfigurable circuit that can be reconfigured, a circuit that combines a reconfigurable electronic circuit (FPGA) 107 and an optical free circuit as shown in FIG. 6 was used. A sheet-like optical transmission medium 101 is applied to the optical free circuit. This embodiment is characterized in that all the electronic devices 107 are FPGAs, that an optical free circuit is applied for optical connection, and that the design method shown in FIG. 9 is used.

As a reconfigurable electronic device, nine FPGAs ([1,1] to [3,3]) having 400,000 gates are mounted and interconnected by an electric wiring and an optical free circuit 101. The size of the substrate is 3.5 cm □. Also, as shown in FIG. 6B, an electronic module having an FPGA 107 and an electric wiring layer 105, and an optical module having a two-dimensional waveguide 101 and an optical port 102 are stacked in a layered structure, so as to be compact. Has been implemented. Further, the adjacent FPGAs are connected by 32 electrical wirings by the electrical wiring layer 105. The configuration of the optical free circuit is selected from the optical connection book in the design method described later.

In the optical connection, an electrical signal output from one FPGA 107 is converted into an optical signal in the optical port 102, and the optical signal propagates through the two-dimensional optical waveguide 101 that is an optical transmission medium, and then in another optical port 102. Is input to another FPGA 107. In this way, the FPGAs are connected by both electrical wiring and an optical free circuit. Which is used for signal transmission can be selected by switching the connection terminal inside the FPGA.

Such a reconfigurable optoelectronic circuit of the present embodiment has a configuration of the entire circuit by freely changing the optical connection between the semiconductor chips in addition to changing the internal configuration of the semiconductor chip (FPGA). It is possible to change. That is, the connection between the FPGAs via the optical free circuit can be reconfigured.

A method for designing the photoelectric fusion circuit of this embodiment will be described below.
The processes up to the formation of the net list are the same as in the first embodiment. After performing a schematic system design 21 based on the required specification 20, a circuit connection list (net list) 10 is generated through a logic design 22 and a circuit design, and based on this, a photoelectric characteristic characteristic of this embodiment is created. Perform integrated layout design.

In the system design of this embodiment, it is not always necessary to assign an electronic circuit and an optical connection. Of course, assignment may be performed as a provisional initial design, but it is assumed that it will be changed in a later photoelectric fusion layout design.

The above-described photoelectric fusion layout process will be described with reference to FIG.
In this process,
・ Steps to design electronic circuit layout (placement and routing) based on netlist 10.
・ Steps of design evaluation with branches,
Assigning part of the net to the optical connection,
・ Steps to design the optical circuit,
Have

Hereinafter, the contents of each step will be described along the flow.
First, component layout, electrical wiring, and electronic circuit analysis are performed as the first electronic circuit layout design. The electronic circuit layout design conforms to the electronic circuit layout design 18 of the first embodiment. However, although it is desirable that the first design here satisfies the required specifications (circuit speed, circuit area, power consumption, etc.), it does not necessarily have to be satisfied. This is because improvement can be expected in the following flow. In that sense, it is sufficient to design with a lighter load than the conventional layout design. In particular, setting the design time of the electronic circuit layout in advance is effective in reducing the design time. In this case, the optimum solution among the solutions obtained in the design time is used as a result, and the process proceeds to the next step.

Next, the first design evaluation is performed. In the design evaluation, evaluation is made such as how much the result of the first electronic circuit layout design meets the required specifications (circuit speed, circuit area, power consumption, etc.) and where there is a problem. Make a decision based on this,
Judgment A: Proceed to the flow of optical connection, aiming to improve the design,
Judgment B: Output layout information and finish the design (proceed to the next step),
Proceed to either.

Judgment criteria can be arbitrarily set by the designer. For example, circuit speed, power consumption, number of gates, circuit area, total wiring length of electronic circuit, and the like can be mentioned. These can be set with priorities, or weights can be set to set a target function, and this can be calculated to determine whether the evaluation is good or bad. For example, in the simplest case, it may be judged A when the specification is not satisfied (no), and judged B when the specification is satisfied (yes).

In the case of determination A, the process proceeds to an optical connection assignment step. Save analysis results such as layout results and delay calculations before migrating.

Here, a part of the netlist is assigned to the optical connection. As a result, an optical net is generated (updated if it already exists). In addition, a net list excluding a portion assigned to the optical net is generated as an electric net. In this assignment, a plurality of electrical wirings can be assigned to the optical connection. For example, it is conceivable that a plurality of parallel wires are assigned to a one-to-one serial optical connection, or a plurality of fan-out signals are assigned to a broadcast optical connection.

At this time, which net is assigned to the optical connection can be randomly assigned or assigned based on an assignment guideline. The former can be assigned at high speed, and the latter can be assigned with high accuracy for performance improvement.

When performing allocation based on the guideline, the selection is made based on the layout results, circuit analysis results (such as electrical wiring delay results), optical module constraints, and the like. As a guideline for assignment, assign a net that transmits high-speed signals, assign a net that requires long-distance connection, assign a net that goes through many vias, assign a net that has a larger wiring path than the straight line distance, and high fan Allocate -out nets, high fan-in nets, parallel wiring, etc.

Next, optical circuit design and analysis are performed for the optical network. In the optical circuit design, the design shown in FIG. 2 is applied. In this embodiment, hundreds of types of optical connection books are stored in a storage device (optical connection library). As the optical connection book, various configurations such as an optical transmission medium configuration, an optical port configuration, an optical port position, and an optical port type are prepared. In this embodiment, by selecting (changing) the optical connection book and repeating the optical connection design procedure from the optical connection library, a preferred optical connection book is selected, and the optical circuit design result 24 is obtained.

Here, the selection of the optical connection book may be performed at random, or the optical connection book having the appropriate number of optical ports may be selected in view of the number of optical nets. In the optical connection design, each optical network is assigned to an optical connection in the optical connection book.

In the optical connection analysis, it is determined whether to continue the repetition or to proceed to the electronic circuit layout. For example, if the optical connection specification is satisfied, the result is stored and the process proceeds to the electronic circuit layout design. If the specification is not satisfied, the process returns to the change of the optical connection book.

When returning to the change of the optical connection book, the optical connection design is performed using the new optical connection book. In changing the optical connection book, basically, another optical connection book is newly applied. However, a new optical port may be added, the type of the optical port may be changed, the position of the optical port may be changed, and the like. In this way, a plurality of optical connection books are repeatedly designed. The design result is updated when a more preferable result is obtained, and retained at other times. In this way, it is possible to improve the design of the optical connection to a good one while sequentially updating the optical connection book. Moreover, even if it changes repeatedly, when improvement is not made, it can return to the design of an electronic circuit layout.

After designing the optical connection, a second electronic circuit layout is designed based on the electric net. The design method can be performed by the same method as the first time. However, in this case, since a part of the net is assigned to the optical connection as compared with the previous time, the electric net of the part is reduced as compared with the previous electric net (initial net list). On the other hand, the number of parts called optical ports has been increased, and wiring and electronic circuits to the optical ports have been added. Since the contents of the electric net have changed, the optimal solution is different for the first and second electronic circuit layout designs.

The second design may be newly designed separately from the first design, or may be improved based on the first design result. As for the latter, for example, it is conceivable to preferentially replace the arrangement of components connected to the optical port. Further, in the timing analysis, it is preferable to perform analysis in consideration of both the delay result of the electric net and the optical net (including the added portion).

Subsequently, the second electronic circuit layout design is completed, and the second design evaluation is performed. This step can be performed in the same manner as the first design evaluation described above. That is, judgment A or judgment B is selected based on the design evaluation criteria. As the determination criteria, circuit speed, power consumption, number of gates, circuit area, total wiring length of electronic circuit, and the like can be cited as in the first time. In addition, regarding the optical connection, the effective utilization of the optical port can be used as a reference.

In the second and subsequent evaluations, it is possible to make a judgment based on whether the result is improved or worsened compared to the previous and past results. In addition, the number of times this design evaluation step is performed can be one of the criteria for judgment.

For example, in the second and subsequent times, the determination criteria are added by combining the comparison with the previous result as follows (see FIG. 9B).
・ If the result is improved compared to the previous time and meets the specifications, it will be judged as A.
・ If the result is improved compared to the previous time and does not meet the specifications, it is also judged as A.
・ If the result is worse than the previous time but does not meet the specifications, it is judged as A.
-When the result is worse than the previous time and the specification is satisfied, as the decision B, the previous result is adopted and the design is finished.

In the second and subsequent optical net allocation, in addition to the existing optical net, a part of another electric net can be added to the optical net. In addition, an existing optical net can be deleted, and another electric net can be newly transferred to the optical net. However, the initial netlist is always present on either the electrical or optical net.

The design of the optical circuit after the second time can be performed in the same manner as the first time. In selecting the optical connection book, it is preferable to use the same optical connection book as the previous result first.

By repeating such a flow, the design can be gradually improved to a good quality. That is, after allocating a part of the net to the optical connection, the electronic circuit is laid out and evaluated many times, and a more optimal design can be realized.

Such a method has the following merits.
In the conventional electricity-only design, the layout and wiring are redesigned many times until the specification is satisfied, and thus the layout and wiring often requires a lot of time. In addition, there was little redundancy and flexibility for changing specifications. However, in the present embodiment, by having a flow option for a new optical connection, the efficiency of design can be increased and the redundancy with respect to a specification change or the like is remarkably improved. Furthermore, the design speed is fast due to the optical connection design using the optical connection book.

In addition, in the design method of this embodiment, in addition to the optimal design of each of the optical circuit and the electronic circuit, the optimization design of the device arrangement, the electrical wiring, and the optical connection configuration as a whole of the photoelectric fusion circuit is comparatively performed. The design method is provided in a short time. The optoelectronic circuit of this embodiment designed in this way is designed to make the best use of the performance of the hardware and has high cost performance. In particular, an optoelectronic circuit having an optical free circuit has the advantage that the degree of freedom of optical connection is remarkably high. On the other hand, since the degree of freedom is high, there are many options and it is difficult to perform optimal design. However, an efficient and sufficiently good design could be performed by using the design method as described above.

In addition, since the design of the electronic circuit and the design of the optical connection are alternately and time-sequentially performed, the process is linearly performed and the stability of the design flow is excellent. Furthermore, a general electronic circuit design tool can be used for the design portion of the electronic circuit layout, and thus the above design method is excellent in compatibility with a general electronic circuit design tool. In addition, the design of this embodiment has features such as high reliability, high reproducibility, and easy reuse of design assets.

In reconfigurable electronic circuits such as FPGAs, with the increase in scale and high integration, in particular, the influence of electrical wiring delay increases, and the time and cost required for design optimization tend to increase. On the other hand, in a system that requires real-time reconfiguration, circuit design in a shorter time is desired. In addition, there is a method to electrically connect multiple FPGAs to increase the scale, but the electrical wiring between chips is fixed and lacks flexibility, so a reconfigurable circuit spans multiple chips. As a result, the limit was large.

The reconfigurable optoelectronic circuit used in this embodiment solves this problem by interconnecting FPGAs with an optical free circuit. The optical free circuit is essentially capable of complete coupling, and further has a high degree of freedom in connection, such as being capable of multicast transmission. In the optical connection book prepared in the present embodiment, the connection between optical ports can be changed (reconfigured) by selecting the transmission destination by changing the radiation angle and propagation direction of the optical signal from the transmission optical port. Further, the optical circuit can be reconfigured by selecting data at the reception optical port. Specifically, the transmission optical port can transmit information to a desired reception optical port by assigning an address or the like as a packet signal to broadcast transmission, and selecting the address by the reception optical port. .

In this way, by connecting the FPGAs with an optical free circuit, reconfiguration across a plurality of chips can be performed with a high degree of freedom. With such a configuration of the optoelectronic circuit, in addition to being large-scale, it is a reconfigurable circuit having high speed and flexibility. Furthermore, such an optoelectronic circuit can alleviate the RC signal delay and EMI problems of the in-chip wiring by using an optical connection, thereby realizing a large-scale and high-speed reconfigurable circuit.

In addition, the above-described reconfigurable optoelectronic circuit can change the circuit based on configuration data that is information output by the design of the optoelectronic circuit. A reconfigurable optoelectronic circuit can reconfigure the circuit by reading configuration data from the outside. By rewriting the configuration data, the electronic circuit in the FPGA is reconfigured. Furthermore, by rewriting the configuration data, connection changes (reconfiguration) between the FPGAs via an optical free circuit such as selection of an optical port are made. More specifically, based on the configuration information, the optical connection is reconfigured by changing the emission angle and the emission direction at each optical port.

In this way, both the electronic circuit (inside the FPGA and the electrical connection between the FPGAs) and the optical connection (the connection between the optical ports) can be reconfigured based on the configuration information. Also, depending on the configuration data, it can be reconfigured over the entire optoelectronic circuit, or only a limited portion can be partially reconfigured.

In this embodiment, an FPGA is used as a reconfigurable electronic circuit, but this is not particularly limited. The reconfigurable electronic circuit is not limited as long as it is a circuit including a logic element whose logic function can be changed and an electric connection network whose interconnection can be changed. The logic element includes an LUT (Look Up Table) that has an input / output truth table relating to a logic function to be realized in a RAM format and outputs an output signal for a combination of inputs. Further, AND, NAND, OR, NOR, XOR, flip-flops, latches, registers, inverters, multipliers, and the like may be included. Furthermore, a memory may be included. In addition, an arithmetic unit (processor) such as integer arithmetic, floating point arithmetic, and function arithmetic may be included.

The electrical connection network can set the connection between the logic elements. For example, the electrical connection network includes electrical wiring and switches arranged in a matrix that connects the logic elements arranged in an array. The switch is arranged at a connection portion between the logic element and the electric wiring, an intersection portion of the matrix wiring, or the like.

Example 4
Example 4 is an example of a photoelectric fusion system (photoelectric fusion reconstruction system) that can be reconfigured in real time. An example of a reconfigurable photoelectric fusion system according to this embodiment is shown in FIG. As shown in FIG. 12A, a circuit (device) 92 for designing an optoelectronic circuit, a reconfigurable optoelectronic circuit 91, a configuration memory 93, and an I / O (light input / output means)
94.

As shown in FIG. 10, the circuit 92 for designing the optoelectronic circuit includes input / output means, storage means 81, design means 82, design evaluation means 83, and control means 84. The storage means 81 stores optical connection book data, netlists, electrical nets, optical nets, various design parameters, design results, intermediate design results, design time, functional specifications as required specifications, design constraints, etc. It is a part. The input / output means is a means for allowing the above-described data to be input from the outside and outputting design results, evaluation results, and the like to the outside.

The design means 82 includes means for generating an electric net and an optical net from the net list, optical port placement means, electronic circuit layout design means (including placement means and wiring means), optical connection design means, and verification means. Furthermore, it has the control means 84 which controls the whole of these design means. In this embodiment, these means are integrated into one chip and mounted as hardware. Thereby, it is possible to implement the same design as Example 1 at high speed.

In the reconfigurable optoelectronic system of the present embodiment, the circuit 92 for designing the optoelectronic circuit based on the input data from the I / O 94 forms (or changes) the design data and designs it in the configuration memory 93. Save the data. The reconfigurable optoelectronic circuit 91 sequentially reads design data from the configuration memory 93 and performs reconfiguration (change of internal configuration). The output from the reconfigurable optoelectronic circuit 91 is output to the I / O 94. In this way, the internal configuration of the optoelectronic circuit 91 can be optimized at any time based on the input data from the I / O 94.

In this embodiment, the optical circuit and the electric circuit are fused, and the design and further reconfiguration can be performed in real time by making the best use of the resources of the photoelectric fusion circuit 91 having a high degree of wiring freedom. That is, it can function as a dynamic reconfigurable system in which the internal configuration of the photoelectric fusion circuit 91 can be freely changed in real time.

In particular, since the photoelectric fusion circuit design using the optical connection book is performed, high-speed design is possible. As a result, the reconfiguration system of this embodiment optimizes the reconfigurable optoelectronic circuit 91 in a short time in a system that requires sequential hardware reconfiguration in response to continuous changes in the operating environment. Since design and reconfiguration can be performed, it can be suitably applied to a control system such as a robot.

In the present embodiment described above, description has been given along FIG. 12A in which the respective parts are interconnected, but a configuration in which the respective parts are connected by the bus 95 as shown in FIG. 12B is also possible. is there. Further, the function of the memory 93 may be performed in the reconfigurable photoelectric fusion circuit 91 or the circuit 92 for designing the photoelectric fusion circuit.

"Example 5"
The fifth embodiment is an example in which a reconfigurable photoelectric fusion circuit is used for designing a photoelectric fusion circuit having a fixed circuit, and a custom photoelectric fusion circuit is designed based on the design result. That is, circuit verification and evaluation are performed using the reconfigurable photoelectric fusion circuit used in the first embodiment, and a custom photoelectric fusion circuit is created based on the output result.

The configuration of the design evaluation apparatus used in this example is shown in FIG. Reconfigurable optoelectronic circuit 91, optoelectronic circuit design means 82, design evaluation of design means 82 mounted on reconfigurable optoelectronic circuit 91 and operated to evaluate the design result Means 83 are provided. That is, the design evaluation apparatus of the present embodiment includes a reconfigurable photoelectric fusion circuit 91 in addition to the photoelectric fusion circuit design apparatus (FIG. 10) used in the first embodiment. Here, as the reconfigurable photoelectric fusion circuit 91, the same hardware as that used in the third embodiment is used.

Using this design evaluation apparatus, a plurality of design results output from the design means 82 are mounted on a reconfigurable optoelectronic circuit 91 and operated to perform performance comparison and function verification. In view of the required specifications, a design result with the most favorable performance is selected. This is called the first design result.

The optoelectronic layout design is performed again based on another custom specification using the electrical net and the optical net derived from the first design result. The main limitation is that the electrical net is realized with an electrical wiring layer and an ASIC or cell-based custom IC. The physical specification of the electrical wiring layer is the same as that of the reconfigurable photoelectric fusion circuit 91. Further, an optical connection book having the same configuration as the output in the reconfigurable optoelectronic circuit 91 was adopted as the optical connection layer.

The method of optoelectronic layout design is in accordance with the method used in the third embodiment. However, in this embodiment, the internal design of the ASIC is made in the electronic circuit layout design. In addition, a circuit implemented across multiple FPGAs can be mounted on a single ASIC. The substrate is square, but size is a design item. The substrate size is set to be as small as possible based on the electronic circuit layout design. Based on this, in the optical connection book, the position of the optical port is reduced while maintaining the positional relationship. The result obtained here will be referred to as a second design result.

Based on the obtained second design result, a new mask is created for the ASIC, the electrical wiring layer, and the optical connection layer to create a custom optoelectronic circuit. Although the reconfigurable photoelectric fusion circuit 91 can change the circuit configuration, the custom photoelectric fusion circuit is a circuit whose configuration is fixed. On the other hand, the custom optoelectronic circuit of this embodiment is not used in the case of the realization of the reconfigurable optoelectronic circuit 91 using the first design result. Therefore, the circuit area can be greatly reduced. In addition, since the configuration of the optical module is an optimal configuration, high performance and miniaturization can be achieved. This can also lead to an improvement in performance such as an increase in operating frequency and lower power consumption.

In this way, in this embodiment, by using the reconfigurable photoelectric fusion circuit 91 as an emulator and designing a custom photoelectric fusion circuit, a high-performance and highly reliable photoelectric fusion circuit can be realized. it can. In addition, by applying the same (similar) configuration as the optical connection book, it is possible to design a photoelectric fusion circuit having high performance in a short design time. In addition, the design method of the optoelectronic circuit of this embodiment is more reliable than the design method using only simulation for verification. In particular, when the circuit scale is large, the design time can be shortened and the design cost can be reduced.

FIG. 5 is a diagram illustrating an example of an optical circuit design method according to the present invention. FIG. 6 is a diagram illustrating another example of the optical circuit design method of the present invention. The figure explaining the example of an optical connection book. The figure explaining the example (sending side) of an optical port book. The figure explaining the example (reception side) of an optical port book. The figure which shows an example of the photoelectric fusion board | substrate used as design object by this invention. FIG. 3 is a diagram illustrating a method for designing an optoelectronic circuit according to the first embodiment. FIG. 9 is a diagram illustrating a method for designing a photoelectric fusion circuit in the second embodiment. FIG. 10 is a diagram showing a method for designing an optoelectronic circuit in Example 3. The figure which shows the structure of the design apparatus of the photoelectric fusion circuit of this invention. FIG. 6 is a diagram illustrating an example of a design result (layout) in the first embodiment. The figure which shows the structure of the reconfiguration | reconstruction system of the reconfigurable optoelectronic circuit of this invention (Example 4). The figure which shows the example of an optical free circuit. The figure which shows the example of the optical coupling part of an optical port. FIG. 10 is a diagram showing a configuration of a photoelectric evaluation circuit design evaluation apparatus used in Example 5; The figure which shows the design flow in the system which has the conventional optical connection and the electronic circuit.

Explanation of symbols

100 substrates
101 Optical transmission medium (two-dimensional waveguide)
102 optical port
105 Electrical wiring layer
106 Electrical wiring
107 Semiconductor chip (reconfigurable electronic circuit)

Claims (3)

It has a laminated structure including a plurality of semiconductor chips, an electric wiring layer, and an optical connection layer, and the optical connection layer performs at least one of a sheet-like optical transmission medium and an optical signal input and output to the optical transmission medium. A design device for a photoelectric fusion circuit having a plurality of optical ports,
A first means for generating, from a net list that is a circuit connection list, an optical net that is a connection list carried by an optical connection;
A second means for assigning the optical net to a first optical connection book having information relating to a set of optical ports capable of optical connection in advance and performing design evaluation;
A second optical connection book having information relating to a set of optical ports capable of optical connection in advance, assigned to the second optical connection book having a different optical port type from the first optical connection book, and performing design evaluation. 3 means,
A fourth means for selecting a design result suitable for the required specification by comparing the design result by the second means and the design result by the third means ;
A design apparatus for an optoelectronic circuit , comprising : 2. The photoelectric fusion circuit according to claim 1 , wherein the optical connection book has an optical port arrangement, a combination of optical ports that can be optically connected, and a data transmission rate that can be transmitted to the combination of optical ports. design apparatus of use. The semiconductor chip has a reconfigurable circuit, for optoelectronic circuit according to claim 1 or 2 further characterized in that the optical connection between the semiconductor chip through the optical connection layer can be changed Design equipment .

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