JP3928172B2 - Wavelength multiplexing communication system and light source for wavelength multiplexing communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wavelength division multiplexing (WDM) communication system using a spectrum slicing technique, and in particular, by replacing a wavelength selection mechanism for slicing and passing, an optical signal of an arbitrary wavelength can be exchanged with one type of communication apparatus. The present invention relates to a wavelength multiplex communication system and a light source for a wavelength multiplex communication system.
[0002]
[Prior art]
Conventionally, in a wavelength division multiplexing communication network in which optical signals of a plurality of wavelengths are propagated in a single optical fiber and a plurality of channels are communicated, a plurality of wavelengths using a single optical fiber can be assigned to each user by assigning different wavelengths. A wavelength division multiplexing communication system that provides communication services to users is known.
[0003]
In this wavelength division multiplexing communication system, as in the example of the wavelength division multiplexing communication system 101 shown in FIG. 6, between the plurality of user side communication apparatuses 11 </ b> A to 11 </ b> D and the center side communication apparatus 12, The optical fibers 14 </ b> A to 14 </ b> D are connected by a single optical fiber 15. One end of each of the optical fibers 14A to 14D is connected to each of the user side communication devices 11A to 11D, and the other end of each of the optical fibers 14A to 14D is connected to the center side communication device 12 via the optical branching module 13. The other end of the single optical fiber 15 is connected. In the above configuration, the user-side communication devices 11A, 11B, 11C, and 11D transmit light having wavelengths (λ1, λ2, λ3, and λ4) assigned to them, while the wavelengths transmitted from the center-side communication device 12 are transmitted. The light of (λ5, λ6, λ7, λ8) is received. The light of the wavelengths (λ1, λ2, λ3, λ4) transmitted by the user side communication devices 11A to 11D is received by the center side communication device 12 via the optical branching module 13 and one optical fiber 15. With the above configuration, the optical branch module 13 between the plurality of user-side communication devices 11A to 11D and the center-side communication device 12 is arranged on a power pole in the vicinity of the user, so that most of the distance can be achieved with one optical fiber 15. Can be connected.
[0004]
As a prior art for realizing this wavelength multiplexing system, there is the following (for example, see Patent Document 1). Patent Document 1 discloses a technique related to a mechanism in which a broadband light source using a spectrum slicing technique and a wavelength slice / bandpass filter for wavelength slicing are provided in one communication apparatus. Therefore, in the conventional wavelength division multiplexing communication system, it is necessary for each user to install a different communication device for each output wavelength.
[0005]
[Patent Document 1]
JP-A-8-237223 ([0003], [0011])
[0006]
[Problems to be solved by the invention]
However, in order to perform wavelength division multiplexing communication in the above-described conventional example, the plurality of user side communication devices 11A to 11D connected to one optical fiber 15 connected to the center side communication device 12 are different from each other. It is necessary to be able to transmit optical signals of wavelengths. Therefore, in the communication method of the conventional example, the user side communication devices 11A to 11D need to correspond to a specific wavelength for each user. Therefore, the user side communication devices 11A to 11D are installed along with the transfer of the user. When the location is changed, it is necessary to replace the user side communication devices 11A to 11D.
[0007]
For this reason, when providing a service by a wavelength division multiplexing communication system as in the conventional example, the service provider manages the wavelengths of the user side communication devices 11A to 11D installed for the user, and the service provider It is necessary to provide the user side communication devices 11A to 11D. Therefore, when a change in the installation location occurs, the service provider needs to replace the user side communication devices 11A to 11D installed on the user side, and there is no freedom for the user to select the communication device, so that there is flexibility. There was a problem that service could not be provided.
[0008]
Therefore, the present invention provides a wavelength division multiplexing communication system and wavelength division multiplexing communication in which the user side communication apparatuses 11A to 11D do not need to be replaced even when the installation locations of the user side communication apparatuses 11A to 11D are changed due to a user's move or the like. An object is to provide a light source for a system.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention applies a combined technique of a broadband semiconductor optical amplification element (appropriately abbreviated as a broadband light source) capable of obtaining a gain in a broadband and a spectrum slicing technique. The spectrum slicing technique is a technique for extracting light having an arbitrary oscillation wavelength by combining a communication device having a broadband light source and an arbitrary wavelength slice / bandpass filter.
[0010]
The light source used in the wavelength division multiplexing communication system according to the present invention has a mechanism capable of separating the broadband semiconductor optical amplifier and the wavelength slice / bandpass filter. The communication device has a broadband semiconductor optical amplifier, and the wavelength slice / bandpass filter is a unit mechanism that can be separated from the communication device into a receptacle (detachable).
[0011]
In the wavelength division multiplexing communication system according to the present invention, one first optical fiber and a plurality of second optical fibers are connected via a branch element, and light of a plurality of different wavelengths propagates through the first optical fiber. , different met WDM communication system for performing optical communication using the channel, the user communication device constituting the wavelength division multiplexing communication system comprises an optical connector receptacle, wherein the optical connector receptacle, the second optical fiber A light-emitting element that emits light to a light source, a broadband semiconductor optical amplifier having a gain of broadband light capable of extracting two or more specific wavelength bands, and a condenser lens that allows the broadband light to pass through, and a wavelength slice・ The bandpass filter unit selects one of two or more types of wavelength slices and bandpass filters each having a different wavelength of light passing therethrough. Selected Any be mounted wavelength slice bandpass filter taking replacement example possible form in the direction in which light is emitted of the broadband semiconductor optical amplifier device has the wavelength slice band-pass filter, the wavelength slice bandpass in a state where the filter unit is mounted in the optical connector receptacle, between said broadband semiconductor optical amplifier and the second optical fiber passes a predetermined wavelength light, the user communication device, the wavelength slice in a state in which the bandpass filter unit is attached to the optical connector receptacle, from the broadband light, extract light of pass wavelength passing through the arbitrary wavelength slice band-pass filter, by emitting different wavelength light , communicate via the second optical fiber, it said.
[0013]
By selecting one wavelength among a plurality of different wavelengths corresponding to the plurality of wavelength slice / bandpass filters by the wavelength division multiplexing communication system as described above, light of any appropriate wavelength is shared by each user side communication device The broadband semiconductor optical amplifying element can emit light.
[0014]
Furthermore, the wavelength division multiplexing communication system according to the present invention is a wideband semiconductor optical amplifying element that can detect two or more different wavelengths of light even when a wavelength shift in the gain characteristic occurs due to a temperature change in a predetermined temperature range. A broadband semiconductor optical amplifier having a gain of a predetermined value or more is provided.
[0015]
With the wavelength multiplexing communication system as described above, a gain of a predetermined value or more can be obtained for light of two or more different wavelengths even when a wavelength shift in the gain characteristic occurs due to a temperature change within the predetermined temperature range. Therefore, since it is not necessary to perform detailed temperature control, the apparatus configuration of the wavelength division multiplexing communication system can be simplified.
[0016]
In the light source for a wavelength division multiplexing communication system according to the present invention, one first optical fiber and a plurality of second optical fibers are connected via a branch element, and light having a plurality of different wavelengths propagates through the first optical fiber. Accordingly, a light source for a wavelength division multiplexing communication system that performs optical communication using a plurality of different channels, a user side communication device that constitutes the wavelength division multiplexing communication system includes an optical connector receptacle, and the optical connector receptacle includes the optical connector receptacle, Yes wideband semiconductor optical amplifier device having a gain of extractable broadband light more than one specific wavelength band be a light emitting element for emitting light to the second optical fiber, and a condenser lens for passing the broadband light, the The wavelength slice / bandpass filter unit is one of two or more types of wavelength slice / bandpass filters each having a different wavelength of light passing therethrough. Selected, the can install any wavelength slice bandpass filter selected in a form replaceable in a direction in which light is emitted of the broadband semiconductor optical amplifier, the wavelength slice band-pass filter, the wavelength slice in a state in which the bandpass filter unit is attached to the optical connector receptacle, between the second optical fiber the broadband semiconductor optical amplifier device, passed through a predetermined wavelength light, the user communication equipment, the With the wavelength slice / bandpass filter unit mounted on the optical connector receptacle, the light of the passing wavelength passing through the arbitrary wavelength slice / bandpass filter is extracted from the broadband light, and the different wavelength light is emitted. And communicating via the second optical fiber, the light source for the wavelength division multiplexing communication system Wavelength slice bandpass filter unit, and a light source for wavelength multiplexing communication system, characterized in that it is configured as the optical connector receptacle.
[0017]
With the light source for wavelength division multiplexing communication system of the present invention, the broadband semiconductor optical amplifying element emits light of a specific wavelength determined by selection of a wavelength slice / bandpass filter installed in the direction in which the optical signal is emitted. The wavelength of the light emitted from the light source can be changed by replacing the wavelength slice bandpass filter with a wavelength slice bandpass filter having a different transmission wavelength.
[0019]
The light source for the wavelength division multiplex communication system selects one of a plurality of different wavelengths corresponding to the wavelength slice / bandpass filter as the wavelength slice / bandpass filter unit, and transmits light of an arbitrary wavelength to each user side. Light can be emitted from the broadband semiconductor optical amplifier common to the communication device.
[0020]
Further, the light source for a wavelength division multiplexing communication system according to the present invention, as the broadband semiconductor optical amplifier, converts light having two or more different wavelengths even when a wavelength shift in the gain characteristic occurs due to a temperature change within a predetermined temperature range. On the other hand, the light source for a wavelength division multiplexing communication system has a gain of a predetermined value or more.
[0021]
The light source for the wavelength multiplexing communication system can obtain a gain of a predetermined value or more for the light of the two or more different wavelengths even when a wavelength shift in the gain characteristic occurs due to a temperature change within the predetermined temperature range. Therefore, it is not necessary to perform detailed temperature control, so that the apparatus configuration of the wavelength division multiplexing communication system can be simplified.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
FIG. 1 is a diagram showing a wavelength division multiplexing communication system 1 according to an embodiment of the present invention. Portions common to those in FIG. 6 are denoted by the same reference numerals and description thereof is omitted. 6 is different from FIG. 6 in that the wavelength multiplexing communication system light source 20 is provided in a receptacle (detachable) form to be described later. FIG. 2 is a diagram showing a configuration of the light source 20 for a wavelength division multiplexing communication system according to an embodiment of the present invention. The light source 20 for a wavelength division multiplexing communication system according to the present embodiment has a configuration capable of separating a broadband semiconductor optical amplifier (appropriately abbreviated as a broadband light source) 21 and a wavelength slice / bandpass filter 22. The user-side communication device has a broadband semiconductor optical amplifier 21, and the wavelength slice / bandpass filter 22 is provided in a wavelength slice / bandpass filter unit 23 that can be separated from the user-side communication device into a receptacle.
[0024]
The broadband light source 21 is installed in the optical connector receptacle 25 together with the condenser lens 24. The wavelength slice / bandpass filter unit 23 can be separated from the optical connector receptacle 25. The optical connector receptacle 25 and the wavelength slicing / bandpass filter unit 23 are not particularly limited as long as they are receptacles. Reference numeral 27 denotes a gain characteristic of the broadband semiconductor optical amplifying element 21, and a high gain is obtained in a wide wavelength band. λ1, λ2,..., λn are pass characteristics of the wavelength slice bandpass filter 22. One of wavelengths λ1, λ2,..., Λn is assigned to the user side communication device.
[0025]
By making the wavelength slice / bandpass filter 22 into the receptacle structure with the wavelength slice / bandpass filter unit 23, all the user side communication devices become the same communication device and can be installed without being aware of the transmission wavelength. By selecting and connecting the wavelength slice / bandpass filter 22 of the wavelength (replacing the wavelength slice / bandpass filter 22 with another wavelength), a wavelength division multiplexing communication system can be realized in any place. Even when the installation location is changed, the user-side communication device is the same device, so it is not necessary to replace the communication device itself, and the installation location can be changed by replacing the receptacle wavelength slice / bandpass filter 22. A wavelength division multiplexing communication system that is the same as that before the change can be realized.
[0026]
FIG. 3 is a diagram showing gain characteristics of the broadband semiconductor optical amplifier 21 with temperature changes. The temperature fluctuation width of the wavelength is 0.5 nm (nanometer) / ° C., and for example, in the range of 0 to 40 ° C., the wavelength shift is 20 nm. In FIG. 3, due to temperature change, the use band indicated by the solid line shifts to the use band indicated by the broken line, and the range indicated by the arrow becomes the use band within the temperature shift. With the wavelength multiplexing communication system as described above, a gain greater than a predetermined value can be obtained for light of two or more different wavelengths even when a wavelength shift in the gain characteristic occurs due to a temperature change within a predetermined temperature range. Therefore, it is not necessary to perform detailed temperature control. Therefore, it is possible to simplify the apparatus configuration for the wavelength division multiplexing communication system.
[0027]
Next, an embodiment of a wavelength division multiplexing communication system constituted by the light source 20 for wavelength division multiplexing communication system of the present invention will be described using FIG. 4 and FIG. FIG. 4 is a diagram illustrating a communication method using a wavelength division multiplexing communication system according to an embodiment of the present invention. The user-side communication device 11 having a broadband semiconductor optical amplifier element (reference numeral 21 in FIG. 2) having the same characteristics can be replaced by the light source for wavelength multiplexing communication system (reference numeral 20 in FIG. 2) of the present invention. By attaching wavelength slice / bandpass filter units 23A to 23D each having a wavelength slice / bandpass filter (reference numeral 22 in FIG. 2) of a specific wavelength, light of a specific wavelength is transmitted from each user-side communication device 11. The
[0028]
Thus, as a replaceable wavelength slice / bandpass filter 22, a plurality of wavelength slice / bandpass filters having wavelength transparency corresponding to a plurality of wavelengths are prepared in advance, thereby providing the wavelength slice / bandpass filter 22. The light emission wavelength can be easily changed simply by replacing the wavelength slice / bandpass filter unit 23, and the user side communication device need not be replaced.
[0029]
In FIG. 4, the number of users is four for simplicity of explanation, but any number of users may be used. In FIG. 4, the same user side communication device 11 is installed in each of the users A to D. A plurality of signal lights of each wavelength (λ5, λ6, λ7, λ8) from the center side communication device 12 are passed through an optical branching element (not shown) in the center device 12 to form one optical fiber (first light). Fiber) 15 and transmitted to the second optical fibers 14-5 to 14-8 via the optical branching module 13 installed on the transmission path, and reach the respective user side communication devices 11.
[0030]
On the other hand, signal light over a wide band from the broadband semiconductor optical amplifying element 21 is emitted from the user side communication device 11. The broadband signal light is assigned to each user by passing through the wavelength slice / bandpass filter units 23A to 23D having a specific wavelength attached in the direction in which the light is emitted to the user-side communication device 11. Sliced into signal light of wavelengths (λ1, λ2, λ3, λ4), transmitted on the second optical fibers 14-1 to 14-4, and passed through the optical branching module 13 to one optical fiber (first optical fiber). Fiber) 15 is transmitted and reaches the center side communication device 12. The wavelengths of the signal light sliced and assigned to each user are λ1, λ2, λ3, and λ4 for users A to D, respectively, and each user communicates using the wavelength of the signal light.
[0031]
FIG. 5 is a diagram illustrating the periphery of the user-side communication device 11 and the wavelength slice / bandpass filter unit 23 (reference numerals 23A to 23D in FIG. 4) in FIG. The user-side communication device 11 (common to all users) includes a broadband semiconductor optical amplification element 21, a condenser lens 24, a glass block 26, and a light detection element 51. The wavelength slice / bandpass filter unit 23 detachably attached to the user side communication device 11 includes an arbitrary wavelength slice / bandpass filter 22.
[0032]
In the user-side communication device 11 shown in FIG. 5, the broadband light emitted from the broadband semiconductor optical amplifying element 21 having a sufficient gain capable of extracting a plurality of wavelengths in a wavelength shift range accompanying a temperature change in a predetermined temperature range is: A glass block with good transparency that passes through the condenser lens 24 and is installed for the purpose of hermetically protecting the broadband semiconductor optical amplifying element 21 and the condenser lens 24 and performing optical coupling with the wavelength slice / bandpass filter unit 23. 26 is passed. The optical spectrum at the time of passing through the glass block 26 is a broadband signal light 52. The broadband signal light 52 travels through an optical fiber in an arbitrarily selected removable wavelength slice / bandpass filter unit 23, and has a wavelength slice / bandpass having an arbitrary transmission characteristic built in the unit 23. Passes through the filter 22. By passing through the wavelength slice / bandpass filter 22, the signal light 52 having a wide band becomes the signal light 53 sliced to a specific wavelength according to the characteristics of the passed wavelength slice / bandpass filter 22. The light sliced by the wavelength slice / bandpass filter 22 is combined with one optical fiber 15 via the optical branching module 13 of FIG. A plurality of channels of wavelength multiplex communication in the form of a single optical fiber 15 is realized.
[0033]
On the other hand, a plurality of wavelengths of signal light of a plurality of channels corresponding to each user transmitted from the center side communication device 12 are second optical fibers 14-5 for each wavelength allocated to each user via the optical branching module 13. 14-8 is transmitted, and reaches the photodetecting element 51 of the user side communication device 11, thereby realizing a wavelength division multiplexing communication system.
[0034]
By using the present invention, the user-side communication device 11 has a broadband semiconductor optical amplification element 21 as a light-emitting element in order to provide a mechanism having a wavelength selection function that can be easily exchanged outside the user-side communication device 11. With the same device. Therefore, unlike the conventional wavelength multiplexing communication system, the wavelength dependency in the user side communication device 11 is not necessary, and the cost can be reduced.
[0035]
In addition, compared with a configuration in which a wavelength selection mechanism for each user is provided in the optical transmission line section, the cost in terms of construction such as optical fiber connection / wiring can be reduced, so that further cost reduction can be realized as compared with the prior art.
[0036]
Further, even when the allocated wavelength is changed due to the transfer of the user or the like, the service provider at the transfer destination can connect the wavelength slice / bandpass filter 22 of an arbitrary wavelength to the user-side communication device 11 with the wavelength slice. By connecting with the band-pass filter unit 23, the user can use the wavelength multiplexing communication service in the same manner as before without changing the user-side communication device 11, and the burden on the user can be greatly reduced. In addition, the burden on service providers can be greatly reduced.
[0037]
The present invention described above can be widely modified without being limited to the above-described embodiment. For example, the light source for a wavelength division multiplexing communication system according to the present invention has been described with respect to application to a user side communication device, but may be applied to a center side communication device. In this case, the effect is less than that applied to the user-side communication device, but it is convenient in terms of maintenance and operation because it can be separated into receptacles.
[0038]
【The invention's effect】
According to the present invention, in the wavelength division multiplexing communication system, the same user side communication device can be used without the user being aware of the type of the user side communication device installed on the user side. Even when the user needs to relocate the installation location, it is not necessary to replace the user side communication device by the user of the wavelength division multiplexing communication system. In addition, the service provider side does not need to manage each user-side communication device for each wavelength, and the service provision cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a wavelength division multiplexing communication system according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a light source for a wavelength division multiplexing communication system according to an embodiment of the present invention.
FIG. 3 is a diagram showing gain characteristics with temperature change of a broadband semiconductor optical amplifier.
FIG. 4 is a diagram illustrating a communication method using a wavelength division multiplexing communication system according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a user-side communication device according to an embodiment of the present invention.
FIG. 6 shows a wavelength division multiplexing communication system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,101 ... Wavelength division multiplexing communication system 11 ... User side communication device 12 ... Center side communication device 13 ... Optical branching module 14-1, 14-2, 14-3, 14-4, 14-5, 14 -6, 14-7, 14-8 .. Optical fiber (second optical fiber)
15 .. Optical fiber (first optical fiber)
20. Light source for wavelength multiplexing communication system 21. Broadband semiconductor optical amplifier (broadband light source)
··· Wavelength slice · Band pass filter 23 · · Wavelength slice · Band pass filter unit 24 · · Condensing lens 25 · · Optical connector receptacle 51 · · Photodetector

Claims (4)

One first optical fiber and a plurality of second optical fibers are connected via a branch element, and light of a plurality of different wavelengths propagates through the first optical fiber, so that light is transmitted using a plurality of different channels. met WDM communication system for performing communication,
A user-side communication device constituting the wavelength division multiplexing communication system includes an optical connector receptacle,
The optical connector receptacle is a light-emitting element that emits light to the second optical fiber, and has a broadband semiconductor optical amplification element having a broadband light gain capable of extracting two or more specific wavelength bands, and allows the broadband light to pass therethrough. A condenser lens;
The wavelength slice / bandpass filter unit selects one of two or more types of wavelength slice / bandpass filters having different wavelengths of light passing therethrough, and selects the selected wavelength slice / bandpass filter as the broadband semiconductor light. Can be mounted in a form that can be replaced in the direction in which the light of the amplification element is emitted ,
The wavelength slice / bandpass filter has a predetermined wavelength light between the broadband semiconductor optical amplifier and the second optical fiber in a state where the wavelength slice / bandpass filter unit is mounted on the optical connector receptacle. is passed through,
The user-side communication device extracts light having a passing wavelength that passes through the arbitrary wavelength slice / bandpass filter from the broadband light in a state where the wavelength slice / bandpass filter unit is attached to the optical connector receptacle. And communicating via the second optical fiber by emitting light of different wavelengths,
A wavelength division multiplexing communication system. The broadband semiconductor optical amplifier, by a gain of more than a predetermined value with respect to light of two or more different wavelengths in the case of any wavelength shift in the gain characteristic due to a temperature change at a predetermined temperature range, to communicate The wavelength division multiplexing communication system according to claim 1 . One first optical fiber and a plurality of second optical fibers are connected via a branch element, and light of a plurality of different wavelengths propagates through the first optical fiber, so that light is transmitted using a plurality of different channels. What source der for WDM communication system for performing communication,
A user-side communication device constituting the wavelength division multiplexing communication system includes an optical connector receptacle,
The optical connector receptacle is a light-emitting element that emits light to the second optical fiber, and has a broadband semiconductor optical amplification element having a broadband light gain capable of extracting two or more specific wavelength bands, and allows the broadband light to pass therethrough. A condenser lens;
The wavelength slice / bandpass filter unit selects one of two or more types of wavelength slice / bandpass filters having different wavelengths of light passing therethrough, and selects the selected wavelength slice / bandpass filter as the broadband semiconductor light. Can be mounted in a form that can be replaced in the direction in which the light of the amplification element is emitted ,
The wavelength slice / bandpass filter has a predetermined wavelength light between the broadband semiconductor optical amplifier and the second optical fiber in a state where the wavelength slice / bandpass filter unit is mounted on the optical connector receptacle. is passed through,
The user-side communication device extracts light having a passing wavelength that passes through the arbitrary wavelength slice / bandpass filter from the broadband light in a state where the wavelength slice / bandpass filter unit is attached to the optical connector receptacle. and, by emitting different wavelength light, it communicates through the second optical fiber,
The light source for a wavelength division multiplexing communication system is configured as the wavelength slice / bandpass filter unit and the optical connector receptacle . The broadband semiconductor optical amplifying element communicates by having a gain of a predetermined value or more with respect to light of two or more different wavelengths even when a wavelength shift in a gain characteristic is caused by a temperature change in a predetermined temperature range. The light source for a wavelength division multiplexing communication system according to claim 3 .

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