JPH0774878B2 - Optical switch array - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical switch array suitable for connecting signal lines such as a communication network and a computer through light.

(Prior Art) Conventionally, a switch array has been an essential device in the fields of communication and computers, and in particular, a crossbar switch is very useful in terms of characteristics.

However, the crossbar switch array is difficult to manufacture when the number of connection terminals is large, and it is not easy to make a large-scale switch array even by making full use of the current semiconductor technology.

Therefore, the crossbar switch is often used for connecting a small number of terminals.

On the other hand, recently, it has been attempted to fabricate a relatively large-scale crossbar switch by introducing optical technology, for example, IEEE SPECTRU.
M, 1986, August issue and IEEE COMPUTER, 1987, June issue (P50) AA
The details are disclosed in Sawchuck et al.

FIG. 7 is a schematic diagram showing a conventional optical crossbar switch. In the figure, 7-1, 7-2, 7-3, 7-4 are light sources, 72
Is the luminous flux emitted from the light source 7-1 etc., 73 is the shutter array, 7
4 is the transmitted light flux from the shutter array 73, 75-1, 75-2, 7
5-3 and 75-4 are photodetectors, respectively.

This configuration example shows an optical crossbar switch having 4 × 4 shutters. The signal from each terminal is the light source
It is sent to 7-1, 7-2, 7-3, 7-4. The luminous flux 72 emitted from the light sources 7-1, 7-2, 7-3, 7-4 is expanded in the vertical direction, and the shutter array 73
Incident on.

In the figure, the shaded portion of the shutter array 73 is the light transmitting portion, and the transmitted light flux 74 from the transmitting portion is collected in the horizontal direction, and the photodetectors 75-1, 75-2, 75- It is incident on 3,75-4. The signals from the photodetectors 75-1, 75-2, 75-3, 75-4 are sent to each terminal.

At this time, which terminals are connected to each other is determined by which shutter of the shutter array 73 is set to the transparent state.

Next, the connection of the light source 7-1 will be described as an example. A signal from a terminal connected to the light source 7-1 is modulated into a light beam emitted from the light source 7-1 and is spread and incident on the first row of the shutter array 73 in the vertical direction. As shown in the figure, for example, when the shutter in the 3rd row and 1st column is a transmissive portion, the incident light flux passes through the shutter only, is collected in the horizontal direction, and is detected by the photodetector 75-3.

Therefore, the terminal of the light source 7-1 is connected to the terminal of the photodetector 75-3. The same applies to connections between other terminals.

However, in the above-mentioned conventional example, when the number of terminals to be connected increases, the number of shutters of the shutter array 73 also increases, which makes it difficult to manufacture.

On the other hand, as a method for reducing the number of switches in an electrical switch array, many other methods than the crossbar switch have been proposed, for example, in "Parallel Computer Architecture" (Shinji Tomita, Shokoido, 1986). There is.

Figure 8 shows a 3-stage cl showing such a switch array.
It is a block diagram of an example of an os network. In the figure, 10 ₁ , 10 ₂ ,
…, 10 ₈ are input terminals, and the number is generally N. Reference _numerals 11 ₁ , 11 ₂ , 11 ₃ and 11 ₄ are P × m crossbar switches, and the number thereof is generally r (where r = N / P). 1
2 ₁ , 12 ₂ and 12 ₃ are r × r crossbar switches, and the number thereof is generally m. Reference numerals 13 ₁ , 13 ₂ , 13 ₃ and 13 ₄ are m × P crossbar switches, which are generally r in number. 14 ₁ , 14 ₂ , 14 ₃ ,
…, 14 ₈ are output terminals, the number of which is N.

It is known that a three-stage clos network becomes a non-blocking network similar to a crossbar switch when m ≧ 2P-1. FIG. 8 shows the case of N = 8, P = 2, r = 4, m = 3, and m ≧ 2P
The condition of -1 is satisfied.

Input terminals 10 _1, 10 ₂ in FIG. 8, ..., with respect to ₁₀₈ (0, 1, 2, 3, ..., 7) output terminal 14 when the allocated number of _1, 14 _2, ..., 14 ₈ , the input terminals 10 ₁ , 10 ₂ , ..., 10 ₈ are connected as (2,5,4,0,7,1,3,6).

The signal from the input terminal 10 ₁ assigned the number 0 is P
The xm crossbar switch 11 ₁ enters and is switched to output. The numbers on the input and output sides of each crossbar switch indicate how the signals of the numbers (0, 1, 2, ..., 7) are sequentially switched. The signal of number 0 is next input to the r × r crossbar switch 12 ₁ and, after output, enters the m × P crossbar switch 13 ₂ and finally the output terminal 14 ₄
Is output to.

The signals from the input terminals 10 ₂ , 10 ₃ , ..., 10 ₈ are also P × m crossbar switches 11 ₁ , 11 ₂ , 11 ₃ , 11 ₄ , r.
Numbering from output terminals 14 ₁ , 14 ₂ , ..., 14 ₈ by switching crossbar switches 12 ₁ , 12 ₂ , 12 _{3 of} × r and crossbar switches 13 ₁ , 13 ₂ , 13 ₃ , 13 ₄ of m × P (, 2,5,4,0,7,
The desired output can be obtained as shown in (1,3,6).

It is known that the number of switches required in a 3-stage clos network is about ▲ 4√ ▼ N ^3/2 -4N when m = 2P-1,
The number is smaller than N ² crossbar switches. This effect becomes more remarkable as N increases.

In FIG. 8, the number of switches is 96, which is larger than the number of switches of the 8-input / 8-output crossbar switch, which is 64. This is because the input / output number N is small.

For example, if N = 1000, the crossbar switch
Although 10 ⁶ switches are required, in the case of a 3-stage clos network, it is about 1.7 × 10 ⁵ .

However, the number of switches in a multi-stage switch array is smaller than that in a crossbar switch, but still requires a large number of switches, which is not easy to fabricate, and the delay time of the signal of each stage accumulates and the transfer delay increases. There was a defect such as a large size.

(Problems to be Solved by the Invention) Even when the number of signal lines to be connected is large, the present invention does not increase the number of shutters in the shutter array by stacking a plurality of shutter arrays in multiple stages, and is easy to manufacture. Moreover, it is an object of the present invention to provide an optical switch array with a simple structure capable of high-speed operation with almost no transfer delay in switching operation.

(Means for Solving Problems) An optical switch array for connecting, using light, a first signal line group and a second signal line group, each of which has a plurality of signal lines, wherein the first signal A plurality of light emitting means arranged in a first direction for emitting light beams respectively modulated according to signals input from the signal lines of the line group; and a second direction perpendicular to the first direction and the first direction. Shutter means in which a plurality of shutters are arranged in the direction, first optical means for spreading the luminous flux emitted from each of the light emitting means in the second direction to enter the shutter means, and transmitting or reflecting the shutter means. In the optical switch array comprising a plurality of light receiving means for receiving the generated light flux and outputting a signal to each signal line of the second signal line group, the shutter means is at least predetermined in the first and second directions. Putter A plurality of shutters are arranged, and a plurality of shutters are arranged in a pattern different from the first shutter array on which the light flux emitted from the light emitting means is incident and the first shutter array in the first and second directions. A second shutter array, and a second shutter array that spreads a light beam transmitted or reflected by the first shutter array in the first direction and makes the light beam incident on the second shutter array.
Optical means.

(Example) FIG. 1 is a schematic diagram of an example of the present invention. 2 is a schematic view of FIG. 1 seen from the Y direction, and FIG.
It is a schematic diagram when a figure is seen from the X direction.

In the figure, 100 is a first signal line group having a plurality of signal lines 100 ₁ , 100 ₂ , ... 101 is a light emitting means for each signal line 100 ₁ , 100 ₂ ,
, And has a plurality of light sources 21 ₁ , 21 ₂ , ... Arranged in the X direction. A first anamorphic optical system 102 has a first cylindrical lens 22 and a first spherical lens 23. Reference numeral 24 denotes a first shutter array, which is in a conjugate relationship with the light emitting means 101 via the first anamorphic optical system 102 in one direction. A second anamorphic optical system 103 includes a second spherical lens 25 and a second cylindrical lens 26.
have. A second shutter array 27 has a conjugate relationship with respect to one direction via the second anamorphic optical system 103. 104 is a third anamorphic optical system,
It has a cylindrical lens 28 and a third spherical lens 29. Reference numeral 30 denotes a third shutter array, which has a conjugate relationship with respect to one direction via the third anamorphic optical system 104. A fourth anamorphic optical system 105 has a fourth spherical lens 31 and a fourth cylindrical lens 32.
Reference numeral 106 denotes a detection means, which is a plurality of photodetectors 33 ₁ , 3 in the Y direction.
It has 3 ₂ , ... 107 is a second signal line group, and includes a plurality of signal lines 107 ₁ , which communicate with the respective photodetectors 33 ₁ , 33 ₂ , ...
107 ₂ , ...

The detecting means 106 has a conjugate relationship in one direction via the fourth anamorphic optical system 105.

In this embodiment, each of the light sources 21 ₁ , 21 ₂ , ... Emits light according to the input data from the signal lines 100 ₁ , 100 ₂ ,. The first anamorphic optical system 102 is arranged so that the light sources 21 ₁ , 21 ₂ , ...
Image is formed, and the light fluxes from the respective light sources 21 ₁ , 21 ₂ , ... Are simply expanded in the Y direction. Second anamorphic optical system 10
3 forms an image of the first shutter array 24 in the Y direction on the surface of the second shutter array 27, and spreads the light flux passing through the first shutter array 24 in the X direction. Similarly below
Anamorphic optical system 104 is the third shutter array 30
Form an image of the second shutter array 27 in the X direction on the surface,
The light flux that has passed through the second shutter array 27 is expanded in the Y direction. The fourth anamorphic optical system 105 forms an image of the third shutter array 30 on the surface of the detecting means 106 in the Y direction, and spreads the light flux passing through the third shutter array 30 in the X direction.

Each of the photodetectors 33 ₁ , 33 ₂ , ... Receives an incident light beam and outputs a signal to each of the signal lines 107 ₁ , 107 ₂ , ... Of the output terminals of the second signal line group 107 connected thereto. .

Next, the operation of the optical switch array of the embodiment shown in FIG. 1 will be described with reference to the drawings. The embodiment shown in FIG. 1 shows a case where the same input / output connection relationship as the switch array of the three-stage clos network shown in FIG. 8 is obtained. That is, the input terminals 10 ₁ , 10 ₂ , ... Of FIG. 8 correspond to the light sources 21 ₁ , 21 ₂ , ... Of FIG. ₁ , and the output terminals 14 ₁ , 14 ₂ , ... Of FIG. It corresponds to each of the photodetectors 33 ₁ , 33 ₂ , ...

Figures 4, 5 and 6 show the first shutter array 2 respectively.
4 is a schematic view of the second shutter array 27 and the third shutter array 30 as viewed from the light emitting means 100 side. FIG. In the figure, the shaded small rectangular areas 42, 44 and 46 are light passing areas with the shutter open, and the shaded small rectangular areas 41, 43 and 45 are
Is an area where light does not pass when the shutter is closed.

In the present embodiment, the first, second and third shutter arrays 24, 27,
Reference numeral 30 is, for example, a liquid crystal, a spatial light modulator using an electro-optical material such as PLZT, LiNbO ₃ , a spatial light modulator using a magneto-optical material such as Bi-substituted YIG, or a type that controls the transmittance of an electrochromy. A display etc. can be used.

Further, the shutter arrays 24, 27, 30 can also use a reflective spatial light modulator that changes the reflectance by utilizing the reflected light.

In FIG. 1, the luminous flux emitted from the light source 21 ₁ is transmitted by the first anamorphic optical system 102 to the first shutter array 2
Illuminate the rightmost column of 4. First shutter array 24
As shown in FIG. 4, since only the shutter 42 is in the passing state in the right column, the light flux passes only from the shutter 42 and enters the second anamorphic optical system 103. The operation at this time is the crossbar switch 11 ₁ whose signal from the input terminal 10 ₁ assigned the number 0 in FIG. 8 is P × m.
It is equivalent to being switched by.

The light flux that has passed through the shutters 42 of the first shutter array 24 illuminates the bottom row of the second shutter array 27 by the second anamorphic optical system 103. The second shutter array 27 has shutters on the bottom row as shown in FIG.
Since only 44 passes, the light flux passes only from the shutter 44 and enters the third anamorphic optical system 104. The operation at this time corresponds to the switching of the signal of number 0 by the r × r crossbar switch 12 ₁ in FIG.

The light flux passing through the shutter 44 of the second shutter array 27 illuminates the fourth row from the left of the third shutter array 30 by the third anamorphic optical system 104. As shown in FIG. 6, in the third shutter array 30, since the shutter 46 in the fourth row from the left is in the passing state, the light flux passes only from the shutter 46 and enters the fourth anamorphic optical system 105. The operation at this time corresponds to the switching of the signal of number 0 by the m × P crossbar switch 13 ₂ in FIG.

Light beam having passed through the shutter 46 of the third shutter array 30 becomes elongated light beam in the X direction by the fourth Anamorufuikku optical system 105 is incident on the photodetector 33 ₄ on the line 5 of the light detecting means 106 . In this case the optical detector 33 ₄ detects the incident light beam, the signal lines of the signal output terminal corresponding thereto
Send to 107 ₄ . That corresponds to a signal marked with a number 0 in Figure 8 is obtained at the output terminal 14 _4.

The light beams emitted from the other light sources 21 ₂ , 21 ₃ , ... Shown in FIG.
It can be seen that the same switching as in the clos network is performed.

When changing the connection pattern in this embodiment,
The light passing states of the switches of the second and third shutter arrays 24, 27, 30 may be changed.

The number of shutters required in the embodiment shown in FIG. 1 is 96, whereas the number of shutters is 64 when the optical crossbar switch shown in FIG. 7 has 8 inputs and 8 outputs.
This is exactly the same as the number of switches in the electrical switch array described above. Therefore, when the number of inputs / outputs N is large, the number of shutters in the optical crossbar switch is three
If the os network is realized by optical connection, the number of shutters will be greatly reduced.

Further, the light propagation time through the optical switch array is very short, and the signal propagation time is the light / electric conversion time of the light sources 21 ₁ , 21 ₂ , ... And the light / electricity of the photodetectors 33 ₁ , 33 ₂ ,. Determined by conversion time. Several hundred semiconductor lasers and PiN photodiodes
The transfer delay is very small because the one operating at MHz can be obtained. Further, this does not affect the transfer delay at all even if the number of stages is increased.

A fiber optical system may be used in place of the anamorphic optical system in this embodiment. For example the light beam from the light source 21 ₁ is incident on the fiber bundle, arranged to irradiate the rightmost first shutter array 24 emitting end of the fiber bundle. Similarly the light beam from the light source 21 ₂ is incident on the fiber bundle, the exit end first shutter array 24
It is configured to irradiate the second column from the right side of. Other light sources 21
_The same applies to ₃ , 21, ₄ .

Next, the first shutter array 24 and the second shutter array 27
Are connected by a fiber optical system so that the light flux from the first row shutter of the first shutter array 24 irradiates the bottom row of the second shutter array 27. At this time, it is necessary to irradiate the entire bottom row of the second shutter array 27 with the light flux that has passed through any shutter in the first row of the first shutter array 24.

Similarly, the second row of the first shutter array 24 is connected by a fiber optical system so as to illuminate the second row from the bottom of the second shutter array 27. The same applies to the third and subsequent rows of the first shutter array 24.

The connection between the second shutter array 27 and the third shutter array 30 is essentially the same as described above. For example, the fiber optics are connected so that the rightmost column of the second shutter array 27 illuminates the top row of the third shutter array 30.

The third shutter array 30 and connection between the optical detection means 106 toward the light flux all the photodetector 33 ₁ from the first row of the third shutter array 30, the light beam is all the photodetector 3 from the second row
3 ₂ across, have gone to constitute the fiber optics as well as the light beam from each row th towards all predetermined photodetector below.

With the above arrangement, an optical switch array can be realized by the fiber optical system. Incidentally, since the description with reference to fiber optics as described in association with the embodiment using the Anamorufuikku optical system shown in FIG. 1, for example, the light source 21 ₁ and the rightmost column of the first shutter array 24 The case of connection is shown. This is because the image formed by the lens system is an inverted image, and therefore the other party to be connected was not positioned in front, and can be positioned in front by changing the arrangement of the shutters.

In addition, if each of the above embodiments is used, not only a 3-stage clos network but also a 5-stage or a 7-stage clos network, m =
When P = r, a multistage optical switch array such as a reconfigurable non-blocking network such as a Memphis network and a Benes network, and a blocking network such as an omega network can be easily realized.

Further, in each of the above-described embodiments, the present invention can be applied as it is even if a light flux that reflects the shutter array is used instead of the light flux that passes through the shutter array.

In the above description, the signal line on the input side of the optical switch array is connected to a light source such as an LED, but since it is sufficient to generate a light beam modulated by a signal, there is a light beam with a uniform intensity distribution. The object of the present invention can be achieved even if the portion is modulated by an optical modulator, a shutter, or the like whose transmittance can be changed.

Further, a light source such as an LED may be placed near a circuit where a signal is generated, and a light beam may be guided from there through an optical fiber to be input to the optical switch array. Also, the output of the optical switch array is an electrical signal photoelectrically converted by the photodetector, but of course when the optical signal is transmitted to another place in the subsequent stage, or when optical processing is performed, the light source is not converted and the optical signal is converted. You may leave it as it is.

(Effects of the Invention) According to the present invention, by configuring a plurality of shutter arrays so as to form a multi-stage stage, an optical switch capable of significantly reducing the number of shutters required as compared with a case where a crossbar switch is configured. An array can be achieved.

Further, since the light beams are spatially propagated and connected as compared with the switch array of the multistage stage by the electric system, it is easy to downsize the entire apparatus, and even if the number of stages is increased, the delay time in the propagation is almost entirely reduced. Not fast optical switch arrays can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of one embodiment of the present invention, FIG. 2, and FIG.
Each of the figures is a schematic view when viewed from the X direction and the Y direction of FIG. 1, FIGS. 4, 5, and 6 are each an explanatory view of one element of FIG. 1, and FIG. Illustration of crossbar switch,
FIG. 8 is a block diagram of a conventional 3-stage clos network. In the figure, 100 is the first signal line group, 100 ₁ , 100 ₂ , ... Are the respective signal lines,
101 is a light emitting means, 21 ₁ , 21 ₂ , ... Is a light source, 102, 103, 104, 105
Are the 1st, 2nd, 3rd, 4th anamorphic optical system, 24, 2
7,30 in turn first, second, third shutter array, a light detecting means 106, 33 _1, 33 _2, ... photodetector, 107 second signal line group,
107 ₁ , 107 ₂ , ... Are signal lines, 22, 26, 28, 32 are the first, second, and
The 3rd and 4th cylindrical lenses, 23, 25, 29 and 31 are in order
They are the 1st, 2nd, 3rd and 4th spherical lenses.

Claims (1)

[Claims] 1. An optical switch array for connecting a first signal line group and a second signal line group, each having a plurality of signal lines, using light, wherein each signal of the first signal line group. A plurality of light emitting means arranged in a first direction for emitting light beams respectively modulated according to a signal inputted from a line, and a plurality of light emitting means in the second direction perpendicular to the first direction and the first direction. A shutter means in which shutters are arranged, a first optical means that spreads the light flux emitted from each of the light emitting means in a second direction to enter the shutter means, and receives a light flux transmitted or reflected by the shutter means. An optical switch array comprising a plurality of light receiving means for outputting signals to the respective signal lines of the second signal line group, wherein the shutter means comprises at least a plurality of predetermined patterns in the first and second directions. shutter A first shutter array on which the luminous flux emitted from the light emitting means is incident, and a plurality of shutters arranged in a pattern different from that of the first shutter array in the first and second directions. A second shutter array, and a second shutter array that spreads a light beam transmitted or reflected by the first shutter array in the first direction and makes the light beam incident on the second shutter array.
An optical switch array comprising: