JP5063558B2 - Optical repeater - Google Patents

Description

  The present invention relates to a technique for relaying an optical signal in an optical transmission network.

  As the demand for data communication increases, optical transmission networks using wavelength division multiplexing technology capable of transmitting large volumes of traffic are becoming widespread. In such an optical transmission network, a metro network that accommodates access traffic, forwards traffic in the city, and bridges the core network constitutes a ring network as shown in FIG. In general, these are connected to each other.

In an optical repeater for connecting between rings as shown in FIG. 1, it is desired to pass an optical signal between rings as much as possible from the viewpoint of economically constructing a network.
Y. Nishida, H. Miyazawa, M. Asobe, O. Tadanaga, E. Kubota, and H. Suzuki, "Efficient parametric wavelength conversion using direct-bonded QPM-ZnO-doped LiNbO3 ridge waveguide," in Proc. CLEO2004, San Francisco, USA, May 2004, paper CFA4 : J. Yamawaku, H. Takara, T. Ohara, K. Sato, A. Takada, T. Morioka, O. Tadanaga, H. Miyazawa, and M. Asobe, "Inter-band wavelength conversion of 25 GHz-spaced 1.03 Tbit / s (103 x 10 Gbit / s) DWDM signals with small guard and low crosstalk in PPLN waveguide, "in Proc.CLEO2003, Baltimore, USA, Jun. 2003, paper CThPDB2 Asobe, M .; Tadanaga, O .; Miyazawa, H .; Nishida, Y .; Suzuki, H .; "Multiple quasi-phase-matched device using continuous phase modulation of / spl chi // sup (2) / grating and its application to variable wavelength conversion ", Quantum Electronics, IEEE Journal of Volume 41, Issue 12, Dec. 2005 Page (s): 1540-1547

  In the ring network as shown in FIG. 1, since the path is basically set by assigning the wavelength uniquely in each ring, for example, when the path is set across the ring 1 and the ring 2, the ring Since λ1 is free at 1, even if the wavelength of λ1 is assigned to the path, λ1 is not always free at ring 2, and in this case, λ1 cannot be used at ring 2. That is, when a path having the same wavelength is set across the ring 1 and the ring 2, the number of wavelengths that can be used is limited. Therefore, it is desirable to provide a wavelength conversion function in an optical repeater that performs inter-ring connection.

  Even if the target signal light does not cross the ring network, if the same wavelength as the target signal light is input from another route in the network or from the input port for ADD, the wavelength A collision occurs. In this case, by converting the wavelength of the target signal light, it is possible to convert the wavelength to a free wavelength and accommodate the signal light in the ring network. This applies not only to the ring network but also to the mesh network.

  As a wavelength conversion function, it is conceivable to use a wavelength conversion device that uses a single device and a device that can simultaneously convert a plurality of wavelengths. As such a wavelength conversion device, there is a device using a QPM-LN (Quasi-phase matching LiNbO3) waveguide, a highly nonlinear optical fiber, or the like. As shown in FIG. 2, when the signal light (generally, multi-wavelength light) and pump light are input, the devices used in these wavelength converters have the wavelength of the signal light folded around the wavelength of the pump light. It has the characteristic of outputting light as converted light (Non-Patent Documents 1 to 3).

  An example of the configuration of the optical repeater is shown in FIG. FIG. 3 shows a configuration example for performing inter-ring connection from ring 1 to ring 2 by adding signal light transmitted on ring 1 to ring 2.

  As shown in FIG. 3, the optical repeater 10 includes an optical coupler 11, a duplexer (AWG (Arrayed-waveguide-grating), etc.) 12, a wavelength conversion processing unit 13, a multiplexer (AWG, etc.) 14, an optical A coupler 15 is provided. The duplexer 12 has a function of wavelength-separating the wavelength-multiplexed signal light and outputting the signal light of each wavelength from each output port. In the duplexer 12, the signal light of each wavelength is output from a predetermined output port. The multiplexer 14 has a function of wavelength-multiplexing and outputting signal light of each wavelength input from each input port. The wavelength conversion processing unit 13 is a functional unit that performs wavelength conversion processing on the signal light output from the corresponding output port in the duplexer 12.

  In the configuration shown in FIG. 3, wavelength-multiplexed signal light transmitted through the ring 1 is branched by the optical coupler 11 and input to the demultiplexer 12. The signal light is wavelength-separated in the demultiplexer 12, and the signal light having the wavelength inserted into the ring 2 is input to the wavelength conversion processing unit 13. Each wavelength conversion processing unit 13 performs wavelength conversion processing, and outputs the signal light of each wavelength to the multiplexer 14. The multiplexer 14 synthesizes the wavelength of the signal light of each wavelength and outputs it to the ring 2. To do.

  In the configuration shown in FIG. 3, since the correspondence between the output port of the duplexer 12 and the wavelength is fixed, the output port corresponding to each wavelength is individually provided with the wavelength conversion processing unit 13 for that (input) wavelength. There is a need. Further, as described above, from the viewpoint of effective use of wavelength resources, for example, when setting a path that spans between ring 1 and ring 2, wavelengths that are vacant in each of ring 1 and ring 2 are arbitrarily assigned to the path. Need to be able to. That is, each wavelength conversion processing unit 13 in the inter-ring connection device 10 needs to be configured to be able to arbitrarily select the wavelength of the conversion destination for the wavelength of the input signal light from the wavelengths used in the ring 2. .

  FIG. 4 shows an example in which the optical repeater 10 is used as an optical repeater in the ring 1. As shown in FIG. 4, the wavelength-multiplexed signal light transmitted through the ring 1 is branched by the optical coupler 11 and input to the demultiplexer 12. The signal light is wavelength-separated in the demultiplexer 12, and the signal light having a wavelength that is inserted again into the ring 1 is input to the wavelength conversion processing unit 13. Each wavelength conversion processing unit 13 performs wavelength conversion processing, and outputs the signal light of each wavelength to the multiplexer 14, and the multiplexer 14 synthesizes the wavelength of the signal light of each wavelength and outputs it to the ring 1. To do. Here, signal light from other routes in the same network or ADD-added signal light is also combined and accommodated in the ring 1.

  Also in the configuration shown in FIG. 4, since the correspondence between the output port of the duplexer 12 and the wavelength is fixed, the output port corresponding to each wavelength is individually provided with a wavelength conversion processing unit 13 for that (input) wavelength. There is a need. In addition, as described above, from the viewpoint of effective use of wavelength resources, for example, vacant wavelengths are allocated arbitrarily for each of the signal light of ring 1 and the signal light input from the other path or the signal light to be added. Need to be able to That is, each wavelength conversion processing unit 13 in the optical repeater 10 arbitrarily sets the wavelength of the conversion destination with respect to the wavelength of the input signal light to a wavelength that does not collide with the signal light input from the other path or the signal light to be added. The configuration must be selectable.

  From this point of view, the wavelength conversion processing unit 13 of the optical repeater 10 shown in FIGS. 3 and 4 has the configuration shown in FIG. As shown in FIG. 5, each wavelength conversion processing unit 13 includes an optical switch that outputs input signal light to a desired output port, and each wavelength conversion device (QPM-LN waveguide) corresponding to each wavelength of the conversion destination. Etc.). By adopting such a configuration, it is possible to convert the input signal light of each wavelength into an arbitrary wavelength. However, as shown in FIG. 5, this configuration requires a wavelength conversion device for a plurality of wavelengths on the output side for each of the wavelengths on the input side, which complicates the device configuration. In addition, the apparatus cost becomes very high.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a technique for realizing an optical repeater having a wavelength conversion function used in an optical transmission network with a simple configuration.

In order to solve the above problems, the present invention provides an optical repeater used in an optical transmission network, an input port for receiving signal light from the first optical transmission network, and two or more output ports. A wavelength selective switch having a function of outputting a signal light having a wavelength arbitrarily selected from a plurality of wavelengths included in the signal light from an arbitrary output port, and a plurality of two or more receiving signals A wavelength multiplexing means for outputting a signal light obtained by wavelength multiplexing the signal light input to each of the plurality of input ports to a second optical transmission network, an output port of the wavelength selective switch, and the wavelength A wavelength conversion process is performed on the signal light output from the output port, and the signal light subjected to the wavelength conversion process is connected to the input port of the multiplexing means. And a least one multiple wavelength converting means for inputting said multi-wavelength conversion unit includes an input port for inputting a signal light output from the output port of the wavelength selective switch, and two or more of the plurality of output ports A first wavelength selective switch having a function of outputting a signal light having a wavelength arbitrarily selected from a plurality of two or more wavelengths included in the signal light from an arbitrary output port, and 2 for receiving the signal light The plurality of input ports, a second wavelength selective switch that wavelength-multiplexes the signal light input to each of the plurality of input ports and outputs the wavelength light to the input port of the wavelength multiplexing means, and the first wavelength selection and a least one wavelength conversion means is connected between the switch input and output ports of the second wavelength selective switch, the wavelength multiplexing means, wavelength selection switch Der is, the wavelength converting means is configured as an optical repeater, characterized in that it comprises a device for outputting the converted light to light of a folding wavelength of the input signal light around the wavelength of the excitation light wavelength The

  The apparatus may include a quasi phase matching secondary optical nonlinear medium or waveguide having a periodic inversion structure, or a highly nonlinear optical fiber.

  In addition, the optical repeater includes two or more wavelength conversion means, and the plurality of wavelength conversion means includes an array type QPM-LN waveguide in which QPM-LN waveguides having different wavelength conversion characteristics are integrated. It is good also as having. In each of the above optical repeaters, the wavelength conversion means has a multi-QPM-LN waveguide that can select one conversion destination wavelength from two or more wavelengths with respect to one wavelength of input signal light. Also good.

  According to the present invention, the wavelength selective switch is provided on the demultiplexing side in the optical repeater that performs the connection between networks, and the wavelength conversion unit is provided at the output port of the wavelength selective switch. An optical repeater having a wavelength conversion function can be realized with a simple configuration. Even when closed to a single network, if the same wavelength as the target signal light is input from another route or add / drop function, a wavelength conversion function is provided to avoid wavelength collision. Even in this case, an optical repeater having a wavelength conversion function can be realized with a simple configuration.

  Embodiments of the present invention will be described below with reference to the drawings. In the present specification, the same reference numerals are assigned to components having the same functions.

  In addition, the wavelength conversion device used in each embodiment described below is a wavelength obtained by turning back the wavelength of signal light such as a QPM-LN waveguide and a highly nonlinear optical fiber around the wavelength of pumping light unless otherwise specified. It is assumed that the apparatus has a device that outputs the converted light as converted light. Note that the wavelength conversion device includes an excitation light source, an excitation light amplifier, an excitation light removal filter, and the like corresponding to the characteristics of devices constituting the wavelength conversion device. In each optical repeater described below, they are not shown, but are provided. That is, the wavelength converter includes a device such as a QPM-LN waveguide and a highly nonlinear optical fiber, a pumping light source, a pumping light amplifier, a pumping light removal filter, and the like. FIG. 6 shows an example of a wavelength converter having a QPM-LN waveguide 1, an excitation light source 2, and an excitation light removal filter 3. In the present embodiment, an example is described in which a QPM-LN waveguide is used as an example of a quasi-phase-matched secondary optical nonlinear medium or waveguide having a periodic inversion structure. Any material can be used as long as it is a phase matching secondary optical nonlinear medium or waveguide.

  Further, in the embodiment described below, the connection target between the ring networks is not limited to the ring network, and can be applied to the connection between various networks. In addition, regarding the embodiment in which wavelength conversion is performed within a single network, the type of network is not limited to a specific type.

(First embodiment)
FIG. 7 shows the configuration of the optical repeater 20 according to the first embodiment of the present invention. As shown in FIG. 7, the optical repeater 20 adds signal light from the ring 1 to the ring 2, and is a 1 × N (1 input N output, N is an integer of 2 or more) wavelength selective switch (WSS). : Wavelength Selective Switch) 21, a predetermined number of wavelength converters 22, and N × 1 (N input 1 output) wavelength selective switch 23. In the example of FIG. 7, six wavelength conversion devices 22-1 to 22-6 are provided as the wavelength conversion device 22. Hereinafter, when not distinguishing each wavelength converter, each of the wavelength converters 22-1 to 22-6 is described as the wavelength converter 22. Ring 1 and ring 2 are physically made of optical fibers, and these may be referred to as a first optical transmission network and a second optical transmission network.

  The 1 × N wavelength selective switch 21 has a function of inputting signal light from an input port and outputting signal light of an arbitrary wavelength from an arbitrary output port among the N output ports. The N × 1 wavelength selective switch 23 has a function of selecting an arbitrary wavelength from the respective signal lights input from the N input ports, performing wavelength multiplexing, and outputting from the output port. Note that “arbitrary” means that it can be appropriately set by remote control or the like. The N × 1 wavelength selective switch 23 corresponds to the input and output of the 1 × N wavelength selective switch 21 reversed.

  As shown in FIG. 7, one of the output ports of the 1 × N wavelength selective switch 21 is connected to the ring 1, and at least one of the output ports of the 1 × N wavelength selective switch 21 is N ×. Directly connected to the input port of the one-wavelength selective switch 23.

  The wavelength converter 22 is provided in an amount that can convert an arbitrary wavelength used in the ring 1 into an arbitrary wavelength used in the ring 2. Of course, when the wavelength used for inter-ring connection is limited to a specific wavelength, the wavelength converter 22 only needs to correspond to the wavelength used for inter-ring connection.

  Due to the nature of the wavelength conversion device 22, a plurality of wavelengths can be converted into a plurality of wavelengths, and the 1 × N wavelength selective switch 21 can output an arbitrary wavelength (or a plurality of wavelengths) to an arbitrary output port. It is not necessary to provide the wavelength converters 22 for all combinations of the wavelengths used in the above and the wavelengths used in the ring 2.

For example, when any wavelength in λ1 to λ4 in the ring 1 can be converted into any wavelength in λ1 to λ4 in the ring 2, the combination of conversions is λ1 <−> λ2 (two ways, The same applies below), λ1 <-> λ3, λ1 <-> λ4, λ2 <-> λ3, λ2 <-> λ4, and λ3 <-> λ4. Here, the wavelength conversion device that can perform the conversion of λ1-> λ2 can also perform the conversion of λ1 <-λ2. The same applies to the other sets. Further, for example, a wavelength conversion apparatus using λ _P as pumping light as shown in FIG. 8 performs wavelength conversion centering on λ _P , so that λ 1 <-> λ 4 and λ 2 <-> λ 3 are converted by one. It can be carried out. When the optical repeater 20 performs wavelength conversion of λ1-> λ4 and λ2-> λ3, the 1 × N wavelength selective switch 21 outputs multiplexed light of the signal light of λ1 and the signal light of λ2. What is necessary is just to output to the output port to which the wavelength converter which uses said (lambda) _P as excitation light was connected.

  Thus, in this embodiment, the wavelength conversion device can be shared for a plurality of wavelengths. Further, since the 1 × N wavelength selective switch 21 can output an arbitrary wavelength to an arbitrary output port, it is not necessary to use a complicated configuration using an optical switch as shown in FIG.

  Next, the operation of the optical repeater 20 will be described. In the figure, an example of the path of the signal light is shown. The same applies to other figures.

  In the configuration shown in FIG. 7, signal light transmitted in the direction shown in the ring 1 is input from the input port of the 1 × N wavelength selective switch 21. In the 1 × N wavelength selective switch 21, an output port directly connected to the N × 1 wavelength selective switch 23 with a part of the wavelength light that does not require wavelength conversion among the wavelengths added to the ring 2, according to a preset setting. Is connected to a wavelength conversion device 22 that performs wavelength conversion on the signal light having a wavelength (which may be plural) that is required to be converted among wavelengths added to the ring 2. Output from the selected output port.

  For example, assume that λ1 is converted to λ2. As shown in FIG. 9, when the wavelength converter 22-3 has the property of converting λ1 to λ2, the 1 × N wavelength selective switch 21 uses the wavelength 1 of the signal light of the ring 1 as the wavelength. Output from the output port to which the converter 22-3 is connected. Further, assuming that it is necessary to convert λ3 and λ4 to λ5 and λ6, respectively, as shown in FIG. 10, the wavelength converter 22-6 has a property of converting λ3 and λ4 to λ5 and λ6, respectively. In this case, the 1 × N wavelength selective switch 21 outputs the signal light of λ3 and λ4 out of the signal light of the ring 1 from the output port to which the wavelength conversion device 22-6 is connected.

  The N × 1 wavelength selective switch 23 wavelength-multiplexes the signal light input from all input ports including each input port connected to the 1 × N wavelength selective switch 21 or the wavelength converter 22, and outputs from the output port. Output and send to ring 2.

  In the optical repeater shown in FIGS. 3 to 5, the output port of the duplexer 12 and the wavelength of the signal light output therefrom are fixed. However, in this embodiment, it is possible to output a signal light of an arbitrary wavelength to an arbitrary wavelength converter using a wavelength selective switch. The optical repeater shown in FIGS. 3 to 5 is not required to have a complicated configuration, and a simple configuration can be realized, and the cost can be reduced as compared with the optical repeater shown in FIGS.

  FIG. 11 is a diagram illustrating a first modification of the optical repeater according to the present embodiment. As shown in FIG. 11, this optical repeater 30 includes an optical coupler 31 on the ring 1, and the input port of the 1 × N wavelength selective switch 21 inputs the signal light branched from the optical coupler 31. Different from the configuration shown in FIG. Even with such a configuration, the same effect as described above can be obtained.

  FIG. 12 is a diagram illustrating a second modification of the optical repeater according to the present embodiment. As shown in FIG. 12, the optical repeater 40 corresponds to a configuration in which the N × 1 wavelength selective switch 23 in the configuration shown in FIG. 7 is replaced with a multiplexer (such as an optical coupler) 41. Even in this configuration, there is an effect that the configuration can be simplified. However, since an optical coupler is used, the loss on the multiplexing side is larger than that shown in FIG.

  FIG. 13 is a diagram illustrating a third modification of the optical repeater according to the present embodiment. As shown in FIG. 13, the optical repeater 50 is connected to the ring 3 in addition to the 1 × N wavelength selective switch 21 connected to the ring 1 and the N × 1 wavelength selective switch 23 connected to the ring 2. N × 1 wavelength selective switch 51. The 1 × N wavelength selective switch 21 and the N × 1 wavelength selective switch 23 are connected similarly to the configuration shown in FIG. That is, at least one of the output ports of the 1 × N wavelength selective switch 21 is directly connected to the N × 1 wavelength selective switch 51 and one or more of the output ports of the 1 × N wavelength selective switch 21. Are connected to the N × 1 wavelength selective switch 23 via the wavelength converter 22.

  The 1 × N wavelength selective switch 21 and the N × 1 wavelength selective switch 51 are also connected in the same manner as the 1 × N wavelength selective switch 21 and the N × 1 wavelength selective switch 23. That is, at least one of the output ports of the 1 × N wavelength selective switch 21 is directly connected to the N × 1 wavelength selective switch 51 and one or more of the output ports of the 1 × N wavelength selective switch 21. Are connected to the N × 1 wavelength selective switch 51 via the wavelength converter 22.

  In the configuration shown in FIG. 13, connection involving wavelength conversion from ring 1 to a plurality of rings (rings 2 and 3) can be performed. The rings 2 and 3 may be a plurality of separate rings, or may constitute a bidirectional ring in one ring network. Rings 2 and 3 can also be a redundant configuration (active ring and spare ring) in one ring.

  In the configuration shown in FIG. 13, among the wavelengths of the signal light input to the 1 × N wavelength selective switch 21, the signal light having the wavelength added to the ring 2 without the need for wavelength conversion processing is selected as N × 1 wavelength. Signal light having a wavelength that requires a wavelength conversion process and is output from an output port directly connected to the switch 23 is output from an output port to which the wavelength converter 22 is connected. Of the wavelengths of the signal light input to the 1 × N wavelength selective switch 21, the signal light having the wavelength added to the ring 3 without requiring wavelength conversion processing is directly connected to the N × 1 wavelength selective switch 51. Signal light having a wavelength that requires a wavelength conversion process is output from the output port to which the wavelength converter 22 is connected.

  FIG. 14 is a diagram illustrating a fourth modification of the optical repeater according to the present embodiment. The optical repeater 60 shown in FIG. 14 has a 1 × N wavelength selective switch between a certain output port in the 1 × N wavelength selective switch 21 and a certain input port in the N × 1 wavelength selective switch 23 having the configuration shown in FIG. 61, a wavelength conversion device 62, and an N × 1 wavelength selective switch 63 (referred to as a multiple wavelength conversion function unit 64) are arranged.

  In the configuration shown in FIG. 14, among the signal light of the ring 1 branched from the optical coupler 31, signal light having a wavelength that does not require wavelength conversion processing is output from an output port directly connected to the N × 1 wavelength selective switch 23. Then, the signal light having the wavelength that requires the wavelength conversion processing is output from the output port to which the wavelength conversion device 22 is connected and the output port to which the multiple wavelength conversion function unit 64 is connected.

  The signal light output from the output port to which the multiple wavelength conversion function unit 64 is connected is appropriately separated by the 1 × N wavelength selective switch 61 in the multiple wavelength conversion function unit 64, and the signal light of each wavelength is set in advance. Output from the output port, passed through wavelength conversion processing in each wavelength converter 62, multiplexed by the N × 1 wavelength selective switch 63, and input to the input port of the N × 1 wavelength selective switch 23. The N × 1 wavelength selective switch 23 outputs signal light in which the signal light from the ring 1 and the signal light that passes through the N × 1 wavelength selective switch 23 in the ring 2 are multiplexed. The configuration shown in FIG. 14 is, for example, the output / input in the 1 × N wavelength selective switch 21 and the N × 1 wavelength selective switch 23 by the number of wavelength conversion devices necessary for wavelength conversion in the configuration in FIG. This can be applied when a port cannot be secured.

  The configuration shown in FIG. 14 is based on the configuration shown in FIG. 11, but the configuration shown in FIG. 7 can similarly include the multiple wavelength conversion function unit 64.

(Second Embodiment)
When ring 1 and ring 2 are connected, signal light is generally added from ring 2 to ring 1 in addition to addition of signal light from ring 1 to ring 2. An example of the configuration for this is shown in FIG. An optical repeater 70 shown in FIG. 15 relates to the embodiment of the present invention, and is configured for connection from the ring 1 to the ring 2 shown in the first embodiment (modified example shown in FIG. 11). The same configuration as 1) is used for the connection from the ring 2 to the ring 1.

  The optical repeater 70 shown in FIG. 15 can connect the ring 1 to the ring 2 and can also connect the ring 2 to the ring 1 and has a simple configuration as in the first embodiment. In this way, the wavelength conversion can be performed.

  However, in the configuration shown in FIG. 15, four wavelength selective switches must be provided, and a wavelength conversion device group must be provided for each of ring 1 and ring 2. Although close to the configuration shown in FIG. 15, the configuration shown in FIG. 16 is also conceivable from the viewpoint of reducing the number of wavelength selective switches.

  As shown in FIG. 16, this optical repeater 80 includes two 1 × N wavelength selective switches on the demultiplexing side shown in FIG. 15 as N × M (N input M output) wavelength selective switches 81 (in this case, N = 2). ). In this configuration, the number of wavelength selective switches is smaller than that in FIG. 15, but the wavelength conversion device group for each of ring 1 and ring 2 must be provided, which is the same as the configuration in FIG. .

  Hereinafter, in the present embodiment, a technology that enables sharing of a wavelength conversion device between rings and enables an optical repeater to be realized with a simple configuration even when the rings are connected bidirectionally will be described. .

  FIG. 17 shows a configuration diagram of an optical repeater 90 according to the second embodiment. As shown in FIG. 17, the optical repeater 90 includes an N × M (N input M output, where N and M are integers of 2 or more) wavelength selection switches 81 and an M × N (M input N output) wavelength. The wavelength converters 82-1 to 82-6 are connected between the N × M wavelength selective switch 81 and the M × N wavelength selective switch 83. Hereinafter, when not distinguishing each wavelength converter, each of the wavelength converters 82-1 to 82-6 is described as a wavelength converter 82.

  Each of the N × M wavelength selective switch 81 and the M × N wavelength selective switch 83 inputs an arbitrary wavelength (one or more) from an arbitrary input port, and outputs an arbitrary wavelength (one or more) from an arbitrary output port. This is a wavelength selective switch having the function of The M × N wavelength selective switch 81 is equivalent to the input and output of the N × M wavelength selective switch 83 reversed.

  In the configuration of FIG. 17, the input port of the N × M wavelength selective switch 81 and the output port of the M × N wavelength selective switch 83 are respectively connected to the rings 1 and 2, and are the output ports of the N × M wavelength selective switch 81. At least one of them is directly connected to the input port of the M × N wavelength selective switch 83. A predetermined number of wavelength converters 82 are connected between the output port of the N × M wavelength selective switch 81 and the input port of the M × N wavelength selective switch 83, respectively.

  N in the N × M wavelength selective switch 81 and the M × N wavelength selective switch 83 may be a number equal to or greater than the number of input / output signal lights. M may be a number equal to or greater than the number obtained by adding 1 which is the number of ports directly connecting the N × M wavelength selective switch 81 and the M × N wavelength selective switch 83 and the number of wavelength converters to be provided. .

  In this configuration, the wavelength conversion device used for wavelength conversion when connecting from ring 1 to ring 2 and the wavelength conversion device used for wavelength conversion when connecting from ring 2 to ring 1 can be shared. , 16 can reduce the total number of wavelength converters.

  For example, when the wavelength conversion from λ3 to λ6 is performed in the connection from the ring 1 to the ring 2, and the wavelength conversion from λ4 to λ5 is performed in the connection from the ring 2 to the ring 1, the wavelength conversion having the characteristics shown in FIG. A single device may be provided. On the other hand, in the configuration shown in FIGS. 15 and 16 under the same assumption, two wavelength converters are required for conversion from ring 1 to ring 2 and for conversion from ring 2 to ring 1.

  Next, an operation example of the optical repeater 90 illustrated in FIG. 17 will be described.

  Signal light is input from the ring 1 to the input port of the N × M wavelength selective switch 81, and signal light is also input from the ring 2 to another input port of the N × M wavelength selective switch 81. Of the wavelengths of both signal lights, the wavelength (one or more) of the wavelengths transmitted to the ring 1 that does not require wavelength conversion processing (including the wavelength of the ring 1 that passes through the optical repeater 90), and Signal light that is wavelength-multiplexed with one or more wavelengths that do not require wavelength conversion processing (including the wavelength of ring 2 that passes through optical repeater 90) out of the wavelengths transmitted to ring 2 is output from the direct connection output port. The signal is directly input to the input port of the M × N wavelength selective switch 83 without going through the wavelength converter 82.

  On the other hand, among the input signal lights, the signal light having a wavelength requiring wavelength conversion processing (which may include a plurality of wavelengths) is an output port of the N × M wavelength selective switch 81 to which the wavelength converter 82 is connected. And is input to a corresponding input port of the M × N wavelength selective switch 83 through a wavelength conversion process.

  Then, the M × N wavelength selective switch 83 outputs the signal light multiplexed with the wavelength to be transmitted to the ring 1 among the wavelengths of the signal light input to each input port to the ring 1 and should be transmitted to the ring 2. The signal light multiplexed in wavelength is output to the ring 2.

  The configuration shown in FIG. 17 is simpler than the configurations shown in FIGS. 15 and 16, and the configuration shown in FIG. 17 may be the same even if the number of rings is further increased.

  FIG. 18 is a diagram illustrating a first modification of the optical repeater according to the second embodiment. This optical repeater 100 is different from the configuration shown in FIG. 17 in that an N × M wavelength selective switch 81 is connected to the ring 1 and the ring 2 via an optical coupler. Also with this configuration, the wavelength converter can be shared between the rings, and a simple configuration can be realized.

  FIG. 19 shows a second modification of the second embodiment. As shown in FIG. 19, the optical repeater 110 includes an N × M wavelength selective switch 101 and a predetermined number of wavelength converters 102. In this configuration, among the wavelengths of both signal lights input from the ring 1 and ring 2, the signal light of each wavelength that requires wavelength conversion processing is output from the output port to which the wavelength converter 102 is connected, and each wavelength conversion is performed. After being processed by the device 102, it is input to each input port. Then, a signal light having a wavelength toward the ring 1 that has undergone processing by the wavelength converter 102 and a signal having a wavelength toward the ring 1 without requiring wavelength conversion processing among the wavelengths of the signal light input from the ring 1 and the ring 2. The light is wavelength-multiplexed and output to the ring 1. Similarly, of the wavelength of the signal light toward the ring 2 that has been processed by the wavelength converter 102 and the wavelength of the signal light input from the ring 1 and the ring 2, the wavelength of the wavelength toward the ring 2 that does not require wavelength conversion processing The signal light is wavelength-multiplexed and output to the ring 2.

  In this configuration, similarly to the configuration shown in FIG. 17, the wavelength conversion device can be shared, and the wavelength conversion device can be reduced. Further, in the configuration shown in FIG. 19, only one wavelength selective switch is required, and a simpler configuration can be realized.

(Third embodiment)
FIG. 20 shows the configuration of the optical repeater in the third embodiment. The optical repeater 120 shown in FIG. 20 is an array type wavelength in which QPM-LN waveguides having different wavelength conversion characteristics are integrated as the wavelength converters 82-1 to 82-6 in the optical repeater 90 shown in FIG. The conversion device 122 (device including a QPM-LN waveguide array) is used. According to this configuration, the wavelength converters 82-1 to 82-6 can be simplified.

  Further, according to this configuration, each QPM-LN device requires a temperature control device and a temperature control circuit, but one temperature control device, one integrated QPM-LN device, In addition, since the temperature control circuit is sufficient, there is an advantage that the temperature control device and the temperature control circuit can be reduced and the size can be reduced. Also, the integration density can be further improved by adopting a configuration in which the output port of the WSS and the input port of the QPM-LN device and the output port of the QPM-LN device and the input port of the WSS are directly coupled in a spatial system. it can.

  The array type wavelength converter 121 can be applied not only to the configuration shown in FIG. 17 but also to all the configurations described in this embodiment.

(Fourth embodiment)
In a wavelength conversion element using a QPM-LN that uses a periodically poled structure, an ordinary uniform periodic structure cannot change the excitation wavelength because the QPM band for the excitation wavelength is narrow. On the other hand, a multi-QPM-LN element (also referred to as a multi-QPM-LN waveguide) that can perform multi-wavelength excitation by performing phase modulation with different periods on a periodically poled structure is known. When this multi-QPM-LN element is used, wavelength conversion of a plurality of signals having different wavelengths becomes possible. In the fourth embodiment, an optical repeater using the multi-QPM-LN will be described.

  FIG. 21 shows the configuration of the optical repeater in the fourth embodiment. The optical repeater 130 shown in FIG. 21 is a multi-QPM that has a plurality of input light conversion destination wavelengths (can be selected from a plurality of wavelengths) as one wavelength conversion device in the optical repeater 90 shown in FIG. -A configuration including an LN waveguide is used. That is, this multi-QPM-LN waveguide can realize the role of a plurality of wavelength conversion devices with one device. In this sense, the configuration shown in FIG. 21 has a smaller number of wavelength conversion devices than the configuration shown in FIG. According to this configuration, since each device can support a plurality of conversion destination wavelengths with respect to one input wavelength, the number of wavelength conversion devices to be provided can be reduced, and the device configuration can be further simplified. Note that the multi-QPM-LN waveguide can be used as a device constituting the wavelength conversion device in all the configurations described in the present embodiment.

(Fifth embodiment)
So far, as an embodiment of the present invention, an optical repeater that connects a plurality of networks has been described. However, the technology according to the present invention is applicable not only to an optical repeater that connects a plurality of networks but also to a wavelength in a single network. The present invention can also be applied to an optical repeater that performs conversion processing. An example of an optical repeater that performs wavelength conversion processing in a single network will be described as a fifth embodiment.

  FIG. 22 shows a configuration of an optical repeater 140 according to the fifth embodiment. This optical repeater 140 has the same device configuration as the optical repeater 20 according to the first embodiment shown in FIG. 7 except that the connection with the ring 2 is not made. Further, the multiple wavelength conversion function unit 64 may be provided in the optical repeater 140 in the same manner as the configuration shown in FIG.

  In the configuration shown in FIG. 22, signal light transmitted in the direction shown in the ring 1 is input from the input port of the 1 × N wavelength selective switch 21. The 1 × N wavelength selective switch 21 outputs signal light of some wavelengths that do not require wavelength conversion from an output port directly connected to the N × 1 wavelength selective switch 23 and requires wavelength conversion according to preset settings. A signal light having a predetermined wavelength (which may be plural) is output from an output port connected to a wavelength conversion device 22 that performs wavelength conversion on the signal light, and the wavelength conversion device 22 performs wavelength conversion, The signal light after wavelength conversion is output toward the N × 1 wavelength selective switch 23. FIG. 22 shows a state of converting λ1 to λ2 and a state of converting λ3 and λ4 to λ5 and λ6, respectively, as in FIG.

  The N × 1 wavelength selective switch 23 wavelength-multiplexes the signal light input from all the input ports including each input port connected to the 1 × N wavelength selective switch 21 or the wavelength converter 22 and outputs it from the output port. , Sent to ring 1.

  As described with reference to FIG. 4, even when closed to a single network, if the same wavelength as the target signal light is input from another route or the add / drop function, a wavelength collision occurs. A wavelength conversion function is required for avoidance, but by adopting the configuration in the present embodiment, an optical repeater having such a wavelength conversion function can be realized with a simple configuration.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

It is a figure for demonstrating a ring network. It is a figure for demonstrating the property of a wavelength converter. It is a figure which shows an example of a structure of the optical repeater which connects between networks. It is a figure which shows an example of a structure of the optical repeater which performs a wavelength conversion process in a single network. 2 is a diagram illustrating in detail a portion of a wavelength conversion processing unit 13 of the optical repeater 10; FIG. It is a figure which shows an example of a wavelength converter. It is a block diagram of the optical repeater 20 which concerns on 1st Embodiment. It is a figure for demonstrating sharing with respect to several wavelengths of a wavelength converter. It is a figure which shows the example of the wavelength conversion by a wavelength converter. It is a figure which shows the example of the wavelength conversion by a wavelength converter. It is a block diagram of the optical repeater 30 which concerns on 1st Embodiment. It is a block diagram of the optical repeater 40 which concerns on 1st Embodiment. It is a block diagram of the optical repeater 50 which concerns on 1st Embodiment. It is a block diagram of the optical repeater 60 which concerns on 1st Embodiment. It is a block diagram of the optical repeater 70 which concerns on embodiment of this invention. It is a block diagram of the optical repeater 80 which concerns on embodiment of this invention. It is a block diagram of the optical repeater 90 which concerns on 2nd Embodiment. It is a block diagram of the optical repeater 100 which concerns on 2nd Embodiment. It is a block diagram of the optical repeater 110 which concerns on 2nd Embodiment. It is a block diagram of the optical repeater 120 which concerns on 3rd Embodiment. It is a block diagram of the optical repeater 130 which concerns on 4th Embodiment. It is a block diagram of the optical repeater 140 which concerns on 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 QPM-LN waveguide 2 Excitation light source 3 Excitation light removal filter 11, 15, 31, 115, 131 Optical coupler 12 Demultiplexer 13 Wavelength conversion process part 14, 41 Multiplexer 21, 61, 121 1 * N wavelength selection Switches 22, 62, 82, 102, 122 Wavelength converters 23, 51, 63, 91, 92, 123 N × 1 wavelength selection switch 64 Multiple wavelength conversion function unit 81, 101 N × M wavelength selection switch 83 M × N wavelength Select switch 135 Multi-QPM-LN waveguide

Claims (4)

An optical repeater used in an optical transmission network,
An input port for receiving signal light from the first optical transmission network and two or more output ports are provided, and signal light having a wavelength arbitrarily selected from two or more wavelengths included in the signal light is arbitrarily selected Wavelength selective switch with the function of outputting from the output port of
Wavelength multiplexing means comprising two or more input ports for receiving signal light, and outputting signal light obtained by wavelength-multiplexing the signal light input to each of the plurality of input ports to the second optical transmission network;
It is connected between the output port of the wavelength selective switch and the input port of the wavelength multiplexing means, performs wavelength conversion processing on the signal light output from the output port, and converts the signal light subjected to wavelength conversion processing to And at least one multiple wavelength conversion means for inputting to the input port,
The multiple wavelength conversion means includes
An input port for inputting signal light output from the output port of the wavelength selective switch, and two or more output ports, and having a wavelength arbitrarily selected from two or more wavelengths included in the signal light A first wavelength selective switch having a function of outputting signal light from an arbitrary output port;
A plurality of input ports that receive signal light, and a second wavelength selective switch that wavelength-multiplexes the signal light input to each of the plurality of input ports and outputs the wavelength light to the input port of the wavelength multiplexing means;
At least one wavelength converting means connected between an output port of the first wavelength selective switch and an input port of the second wavelength selective switch ;
It said wavelength multiplexing means, Ri WSS der, the wavelength converting means, that it has a device for outputting the converted light to light of a folding wavelength of the input signal light around the wavelength of the excitation light wavelength An optical repeater characterized. 2. The optical repeater according to claim 1 , wherein the apparatus includes a quasi-phase-matched secondary optical nonlinear medium or waveguide having a periodic inversion structure, or a highly nonlinear optical fiber. The optical repeater includes two or more wavelength conversion means, and the plurality of wavelength conversion means has an array type QPM-LN waveguide in which QPM-LN waveguides having different wavelength conversion characteristics are integrated. The optical repeater according to claim 1 or 2 . Said wavelength conversion means, for one wavelength of the input signal light, of claims 1, characterized in that it has one destination selectable multi QPM-LN waveguide wavelength from two or more wavelengths 3 The optical repeater of any one of them.

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