Wavelength conversion apparatus

Abstract

This wavelength conversion apparatus is capable of handling ultra-wideband optical signals, reduces the need for replacement of an optical device when the transmission band of an optical signal to be handled is extended, and also improves the wavelength resolution of the optical device. The wavelength conversion apparatus converts the wavelength of an optical signal by a combination of a wavelength selective switch 21-C and a wavelength converter 23-C that are each configured as a single band-capable optical device, and a wavelength band converter 22 that collectively converts wavelength bands. The wavelength conversion apparatus can handle the input of all of an input optical signal of a single wavelength within a specific wavelength band or an arbitrary wavelength band, a single-band WDM optical signal, and a WDM optical signal spanning a plurality of bands. A control mechanism is used to select an optical device to be used according to the situation and adjust the control parameter of each optical device. The wavelength resolution of the switch is improved by adopting the single band-capable optical devices. Wide-band wavelength conversion is facilitated in combination with the wavelength band converter.

Description

Wavelength conversion device

[0001] The present invention relates to a wavelength conversion device applicable to optical signal processing in an ultra-wideband (UWB: Ultra-Wide Band).

[0002] For example, in a telecommunications carrier that manages the transmission paths of various optical signals on an optical communication network, wavelength conversion of an optical signal may be required, for example, in accordance with differences in wavelength specifications in input and output transmission paths.

[0003] In recent optical communication networks, it has been desired to configure the entire network from the input end to the output end only with optical communication devices. That is, by eliminating the need to convert an optical signal into an electrical signal in the middle and realizing transmission of the optical signal as it is, it is possible to suppress the occurrence of delay and realize high-speed and large-capacity data transmission.

[0004] Technologies of wavelength selective switches (WSS: Wavelength Selective Switch) that can be used to switch the transmission path of an optical signal in an optical transmission device such as a ROADM (reconfigurable optical add / drop multiplexer) are disclosed in, for example, Non-Patent Document 1 and Non-Patent Document 2.

[0005] Yasuki Sakurai, "Gridless Wavelength Selective Switch Technology Using LCOS", Journal of the Photonics Society of the Applied Physics Society of Japan "Optics", Vol. 42, No. 5 (2013), pp. 236-241, Internet <URL:https: / / annex.jsap.or.jp / photonics / kogaku / public / 42-05-kaisetsu2.pdf>N. K. Fontaine, M. Mazur, R. Ryf, H. Chen, L. Dallachiesa and D. T. Neilson, "36-THz Bandwidth Wavelength Selective Switch", 2021 European Conference on Optical Communication (ECOC), Bordeaux, France, 2021, pp. 1-4, doi: 10.1109 / ECOC52684.2021.9606114.

[0006] Figure 1 shows a typical example of a wavelength conversion device that corresponds to optical signals in the UWB wavelength range. For example, the U.S. FCC (Federal Communications Commission) defines UWB as wireless communication that uses a 10 dB ratio bandwidth of 20% or more of the center frequency, or a bandwidth of 500 MHz or more.

[0007] The wavelength conversion device in Figure 1 comprises a wavelength selection switch 11-WB, a wavelength conversion unit 12-WB, and a wavelength selection switch 13-WB. The wavelength selection switch 13-WB is composed of multiple wavelength converters 14-1 to 14-M corresponding to the number of corresponding channels M. The upstream wavelength selection switch 11-WB has one input port and M output ports. The downstream wavelength selection switch 13-WB has M input ports and one output port.

[0008] Since it is necessary to accommodate the UWB wavelength range, the wavelength selection switch 11-WB, wavelength conversion unit 12-WB, and wavelength selection switch 13-WB shown in Figure 1 are each configured using optical devices that support ultra-wideband.

[0009] In the wavelength conversion device shown in Figure 1, any input optical signal 15 that allows WDM (Wavelength Division Multiplexing) optical signals in the UWB wavelength range is selected for each wavelength by the wavelength selection switch 11-WB and output as an optical signal 16 to one of the M output ports.

[0010] The optical signal 16 of the wavelength selected by the wavelength selection switch 11-WB is converted to another wavelength by one of the wavelength converters 14-1 to 14-M and output as an optical signal 17 from the wavelength conversion unit 12-WB.

[0011] The wavelength selector switch 13-WB combines the optical signals 17 input from the M input ports and outputs the combined result as an output optical signal 18 to the output port.

[0012] On the other hand, the wavelength band actually used for optical communication is limited to a very small range of wavelengths from 1000 nm to 1675 nm. An example of a further subdivided band division of this wavelength band is shown in Figure 2. In the example in Figure 2, the wavelength bands B1, B2, B3, B4, B5, and B6 are arranged in order from the shortest wavelength f. These wavelength bands B1, B2, B3, B4, B5, and B6 are called the O-band (Original-band), E-band (Extended-band), S-band (Short-wavelength-band), C-band (Conventional-band), L-band (Long-wavelength-band), and U-band (Ultralong-wavelength-band), respectively.

[0013] When actually configuring a wavelength conversion device as shown in Figure 1, it is conceivable that the device will have specifications corresponding to the wavelength bandwidth BW1 in Figure 2, or specifications corresponding to the wavelength bandwidth BW2 in Figure 2. Here, wavelength bandwidth BW1 is the range that includes the entire range of wavelength bands B1 to B6. Wavelength bandwidth BW2 is a narrower range than wavelength bandwidth BW1 and includes the entire range of wavelength bands B3, B4, and B5.

[0014] To configure a device that satisfies the specifications of the wavelength bandwidth BW2 in Figure 2, the wavelength selector switch 11-WB, the wavelength converters 14-1 to 14-M, and the wavelength selector switch 13-WB in the wavelength conversion device in Figure 1 must be made of optical devices with characteristics corresponding to the wavelength ranges of wavelength bands B3 to B5. Furthermore, to configure a device that satisfies the specifications of the wavelength bandwidth BW1, the wavelength selector switch 11-WB, the wavelength converters 14-1 to 14-M, and the wavelength selector switch 13-WB in the wavelength conversion device in Figure 1 must be made of optical devices with characteristics corresponding to the wavelength ranges of wavelength bands B1 to B6.

[0015] Therefore, in order to expand the transmission bandwidth and change to the specifications of wavelength bandwidth BW1 while using a wavelength converter that meets the specifications of wavelength bandwidth BW2, each optical device, such as the wavelength selector switch 11-WB, wavelength converters 14-1 to 14-M, and wavelength selector switch 13-WB, must be replaced with a different optical device with different wavelength characteristics.

[0016] On the other hand, the resolution of a wavelength-selective switch constructed using a broadband optical device for optical signals decreases inversely proportional to the transmission bandwidth due to limitations of the optical system. Figure 3 shows the wavelength characteristics and resolution of a wavelength-selective switch using an optical device with a transmission bandwidth corresponding only to wavelength band B4 (C-band). Figure 4 shows the wavelength characteristics and resolution of a wavelength-selective switch using an optical device with a transmission bandwidth corresponding to wavelength bands B1 to B4 (O-band to C-band).

[0017] The transmission bandwidth for wavelength band B4 (C-band) alone is approximately 4.8 [THz], and the wavelength resolution F1 of the optical device corresponding to this is approximately 50 [GHz]. Therefore, a wavelength selector switch that corresponds only to wavelength band B4 will have a wavelength resolution F1 equivalent to each channel from wavelength λ1 to λ7 in Figure 3, and it will be possible to separate the optical signals of each wavelength for each channel and switch the path individually.

[0018] On the other hand, the transmission bandwidth corresponding to the entire wavelength band B1 to B4 is approximately 35 [THz], and the wavelength resolution F2 of the optical device corresponding to this is approximately 350 [GHz]. Therefore, this optical device operates to treat the entire wavelength range λ1 to λ7 as a single channel. Consequently, the wavelength selection switch corresponding to wavelength band B1 to B4 outputs all the optical signals of the channels λ1 to λ7 in Figure 4 to the same path without separating them. In other words, if the channel spacing of the input optical signal is finer than the wavelength resolution of the optical device, it becomes impossible to separate and individually convert the wavelength of the input optical signal to another desired wavelength.

[0019] This invention has been made in view of the above circumstances, and aims to provide a wavelength conversion device that can handle ultra-wideband optical signals, reduces the need to replace optical devices when expanding the transmission bandwidth of the optical signals being handled, and easily improves the wavelength resolution of the optical device.

[0020] The wavelength conversion device of the present invention comprises: one or more wavelength selection switches having the function of outputting an input optical signal in any direction for each wavelength; one or more wavelength band converters having the function of collectively converting the wavelength of the input optical signal to a wavelength in a different wavelength band determined for each wavelength; one or more wavelength converters having the function of converting the wavelength of the input optical signal to a different wavelength within the same wavelength band; and one or more multiplexers having the function of combining multiple optical signals with different wavelength bands from each other, and is characterized in that it allows the wavelength bandwidth of the wavelengths of the input light and / or output light to encompass multiple wavelength bands, and has the function of outputting an optical signal of a desired wavelength converted by dividing the path for each wavelength of the input optical signal.

[0021] The wavelength conversion device of the present invention can handle ultra-broadband optical signals and eliminates the need to replace optical devices when expanding the transmission bandwidth of the optical signals being handled. Furthermore, it can improve the wavelength resolution of the wavelength selective switch even when handling ultra-broadband optical signals. That is, since wavelength conversion over a wider range than a single band is performed using the wavelength band converter, the range of wavelengths converted by the wavelength converter can be limited to a specific wavelength band. Therefore, optical devices that support only a specific single band can be used as the wavelength selective switch and the wavelength converter. A wavelength selective switch that supports only a single band has high wavelength resolution.

[0022] This is a block diagram showing a generally assumed configuration of a wavelength converter that supports ultra-wideband. This is a schematic diagram showing an example of the division of wavelength bands actually used when performing optical communication. This is a schematic diagram showing the wavelength characteristics and resolution of a wavelength selective switch using an optical device that supports only the C band. This is a schematic diagram showing the wavelength characteristics and resolution of an ultra-wideband wavelength selective switch that supports O-band to C-band. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 1. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 2. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 3. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 4. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 5. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 6. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 7. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 8. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 9. This is a block diagram showing an example of the configuration of a wavelength converter in an embodiment of the present invention - 10. This is a schematic diagram showing an example of the operation sequence of a system including a wavelength converter - 1. This is a schematic diagram showing an example of the operation sequence of a system including a wavelength converter - 2. This is a schematic diagram showing an example of the operation sequence of a system including a wavelength converter - 3. This is a schematic diagram showing example 4 of the operating sequence of a system including a wavelength converter. This is a schematic diagram showing example 5 of the operating sequence of a system including a wavelength converter. This is a schematic diagram showing example 6 of the operating sequence of a system including a wavelength converter.

[0023] Embodiments of the present invention will be described below with reference to the figures. <Configuration Example 1> Figure 5 shows Configuration Example 1 of the wavelength conversion device 101 in an embodiment of the present invention. The wavelength conversion device 101 shown in Figure 5 has the function of accepting the input of a single-wavelength input optical signal 25-C in a specific wavelength band as the target for processing, and has the function of converting this single wavelength of the input optical signal to a desired wavelength within an ultra-broadband wavelength range and outputting the converted output optical signal 28. In the example of Figure 5, it is assumed that the wavelength band of the input optical signal 25-C is the C band. The C band corresponds to wavelength band B4 in Figure 2.

[0024] The wavelength conversion device 101 in Figure 5 includes a Wavelength Selective Switch (WSS) 21-C, an All-Optical Wavelength Converter (AO-WC) 22, wavelength converters (WC) 23-C and 23-L, and an optical multiplexer 24.

[0025] Here, the wavelength selective switch 21-C is composed of a single-band optical device that corresponds only to the C-band wavelength range. Similarly, the wavelength converter 23-C is composed of a single-band optical device that corresponds only to the C-band wavelength range, and the wavelength converter 23-L is composed of a single-band optical device that corresponds only to the L-band wavelength range. The L-band corresponds to wavelength band B5 in Figure 2. The wavelength selective switch 21-C has the function of outputting the input optical signal in any direction for each wavelength.

[0026] In other words, the wavelength selective switch 21-C, wavelength converters 23-C, and 23-L in Figure 5 differ significantly from the wavelength selective switches 11-WB, 13-WB, and wavelength converters 14-1 to 14-M in Figure 1 in that the wavelength characteristics of these optical devices are relatively narrow bandwidth.

[0027] The wavelength selector switch 21-C has one input port and multiple output ports. Here, the number of output ports is B, which corresponds to the number of corresponding bands. The wavelength selector switch 21-C can select any single wavelength as a specific wavelength from within the wavelength range of the C band input as the input optical signal 25-C. The optical signal 26 of the specific wavelength selected by the wavelength selector switch 21-C is output to a specific output port selected from the B output ports.

[0028] Although the example in Figure 5 only shows configurations corresponding to the C-band and L-band, by increasing the number of output ports of the wavelength selector switch 21-C to three or more, and increasing the number of elements of the optical devices corresponding to the wavelength band converter 22 and wavelength band converter 23-L in Figure 5, it is possible to support the entire range of wavelength bands B1 to B6 shown in Figure 2.

[0029] The wavelength band converter 22 has the function of converting the wavelength of the input optical signal to the wavelength of a different wavelength band determined for each wavelength. In the example in Figure 5, the wavelength band converter 22 converts the input C-band optical signal 26 into an optical signal in the L-band wavelength band.

[0030] One wavelength converter 23-C converts the wavelength of the input optical signal 26 to a desired wavelength different from the wavelength of the optical signal 26 within the C-band wavelength range and outputs it as a C-band optical signal 27-C. The other wavelength converter 23-L converts the wavelength of the optical signal 26 to a different desired wavelength within the L-band wavelength range and outputs it as an L-band optical signal 27-L.

[0031] The multiplexer 24 has the function of combining multiple optical signals with different wavelength bands. The multiplexer 24 combines the C-band optical signal 27-C output from the wavelength converter 23-C and the L-band optical signal 27-L output from the wavelength converter 23-L, and then wavelength-converts the combined result to output the output optical signal 28. Therefore, it is possible to generate an ultra-broadband output optical signal 28 that includes both the C-band and L-band wavelength bands. Furthermore, by increasing the number and types of optical devices, it becomes possible to output optical signals in the entire range of wavelength bands B1 to B6 shown in Figure 2.

[0032] In other words, this wavelength converter 101 can expand a single-wavelength input optical signal 25-C in a specific wavelength band to an ultra-broadband including different wavelength bands and output an output optical signal 28 converted to an arbitrary wavelength. For example, if wavelength λa1 is input as the input optical signal 25-C at a certain time t1, the wavelength converter 101 can output wavelength λb1 as the output optical signal 28. Also, if wavelength λa2 is input as the input optical signal 25-C at another time t2, it can output wavelength λb2 as the output optical signal 28. Furthermore, the relationship between wavelengths λa1 and λb1, and the relationship between wavelengths λa2 and λb2 can be changed as needed depending on the conditions of the passing optical signal, such as differences between the source and destination, differences in the path taken, etc.

[0033] In the wavelength conversion device 101 shown in Figure 5, the wavelength selection switch 21-C is composed of an optical device that supports only single bands. Therefore, the wavelength selection switch 21-C has high wavelength resolution. For example, as shown in the example in Figure 3, optical signals with wavelengths λ1 to λ7 can be distinguished for each wavelength channel with a wavelength resolution equivalent to F1 and output to output ports in different directions.

[0034] Furthermore, for example, if the wavelength conversion device 101 shown in Figure 5 is configured to support only wavelength bands B4 and B5, it is possible to expand the supported bandwidth to wavelength bands B1 to B6. In that case, the wavelength selection switch 21-C and the optical devices 23-C and 23-L of the wavelength conversion device 101 do not need to be replaced, and the bandwidth can be expanded simply by adding the missing optical devices.

[0035] The wavelength converter 101 has the function of allowing the wavelength bandwidth of the input and / or output light to encompass multiple wavelength bands and outputting an optical signal of a desired wavelength converted for each wavelength of the input optical signal. Furthermore, the wavelength converter 101 has the function of allowing input of a single-wavelength optical signal whose wavelength falls within a specific wavelength band or any wavelength band, and allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0036] <Configuration Example 2> Figure 6 shows a configuration example 2 of the wavelength conversion device according to an embodiment of the present invention. The wavelength conversion device 102 shown in Figure 6, like the wavelength conversion device 101 in Figure 5, has the function of accepting a single-wavelength input optical signal 25-C in a specific wavelength band as the target for processing, and has the function of converting this single wavelength of the input optical signal to a desired wavelength within an ultra-broadband wavelength range and outputting the converted output optical signal 28. In the example in Figure 6, it is assumed that the wavelength band of the input optical signal 25-C is the C band.

[0037] The wavelength converter 102 in Figure 6, like the wavelength converter 101 in Figure 5, includes a wavelength selector switch 21-C, a wavelength band converter 22, a wavelength converter 23-C, and a multiplexer 24. However, in the wavelength converter 102, the wavelength converter 23-C is located upstream of the wavelength selector switch 21-C. The wavelength band converter 22 is connected downstream of the wavelength converter 23-C. Therefore, in the wavelength converter 102 in Figure 6, the wavelength converter 23-L in Figure 5 is unnecessary, and the total number of optical devices is reduced.

[0038] In the configuration shown in Figure 6, the wavelength selector switch 21-C is composed of a single-band optical device that supports only the C-band wavelength range. Similarly, the wavelength converter 23-C is composed of a single-band optical device that supports only the C-band wavelength range.

[0039] In the wavelength conversion device 102 shown in Figure 6, a single-wavelength input optical signal 25-C in a specific wavelength band is converted by the wavelength converter 23-C to a different desired wavelength within the C-band wavelength range, and then input as an optical signal 31 to the wavelength selection switch 21-C.

[0040] In the wavelength conversion device 102 shown in Figure 6, the wavelength selection switch 21-C can select any single wavelength from the C-band wavelength range input as the optical signal 31 as a specific wavelength as needed. The optical signal 32 of the specific wavelength selected by the wavelength selection switch 21-C is output to a specific output port selected from among the B output ports.

[0041] The wavelength converter 22 has a function of collectively converting the wavelength to a wavelength in another wavelength band determined for each input wavelength. In the example of FIG. 6, the wavelength converter 22 converts the input C-band optical signal 32 into an L-band optical signal 33-L including the wavelength band of the L band.

[0042] The multiplexer 24 outputs, as the converted output optical signal 28, the result of multiplexing the C-band optical signal output from one output port of the wavelength selection switch 21-C and the L-band optical signal 33-L including the wavelength band of the L band output from the wavelength converter 22.

[0043] Therefore, the wavelength conversion device 102 shown in FIG. 6 can also generate an ultra-wideband output optical signal 28 including both the C-band and L-band wavelength bands. Also, by increasing the number and types of optical devices, optical signals in all ranges of the wavelength bands B1 to B6 shown in FIG. 2 can be output.

[0044] The wavelength conversion device 102 has a function of allowing the wavelength bandwidth of the wavelength of the input light and / or output light to include a plurality of wavelength bands, and outputting an optical signal of a desired wavelength converted for each wavelength of the input optical signal. Further, the wavelength conversion device 102 has a function of allowing the input of an optical signal of a single wavelength whose wavelength is within a specific wavelength band or an arbitrary wavelength band as the input optical signal, and allowing the selective output of optical signals of a plurality of wavelengths with different wavelength bands.

[0045] <Configuration Example - 3> A configuration example - 3 of the wavelength conversion device in the embodiment of the present invention is shown in FIG. 7. The wavelength conversion device 103 shown in FIG. 7 has a function of allowing the input of an optical signal 48 of a single wavelength in an arbitrary wavelength band among a plurality of wavelength bands as a processing target, and converting the single wavelength of this input optical signal to a desired wavelength within an ultra-wideband wavelength range and outputting it as a wavelength-converted output optical signal 49. That is, a function corresponding to a signal with a wider bandwidth than the input optical signal 25-C in FIGS. 5 and 6 is added as the input optical signal 48. Also, in the example of FIG. 7, a case where the input optical signal 48 includes optical signals in both the C-band and L-band wavelength bands is assumed.

[0046] The wavelength conversion device 103 in FIG. 7 includes a demultiplexer (optical demultiplexer) 41, a wavelength band converter 42, an optical coupler 43, a wavelength converter 44-C, a wavelength selection switch 45-C, a wavelength band converter 46, and a multiplexer 47.

[0047] Here, the wavelength converter 44-C and the wavelength selection switch 45-C are each configured as single-band optical devices corresponding only to the wavelength band of the C band. The optical coupler 43 has a plurality of input ports equal in number to the corresponding number of bands (B) and one output port. Also, the wavelength selection switch 45-C has one input port and a plurality of output ports equal in number to the corresponding number of bands (B).

[0048] One of the wavelength band converters 42 has a function of collectively wavelength-converting optical signals in the wavelength band of the L band to the C band, and the other wavelength band converter 46 has a function of collectively wavelength-converting optical signals in the wavelength band of the C band to the L band.

[0049] The operation of the wavelength conversion device 103 in FIG. 7 will be described below. The broadband input optical signal 48 is demultiplexed by the demultiplexer 41 for each wavelength band. Then, the C-band optical signal 48-C and the L-band optical signal 48-L are output from different output ports of the demultiplexer 41, respectively. The L-band optical signal 48-L output from the demultiplexer 41 is input to the wavelength band converter 42 and wavelength-band-converted, and is output from the wavelength band converter 42 as the C-band optical signal 51-C.

[0050] The C-band optical signal 48-C output from the demultiplexer 41 and the C-band optical signal 51-C output from the wavelength band converter 42 are each input to the optical coupler 43, and the C-band optical signal 52-C in which they are superimposed is input to the wavelength converter 44-C. The wavelength converter 44-C converts a single wavelength input within the band of the C band to a different desired wavelength and outputs it as the C-band optical signal 53-C.

[0051] The wavelength selection switch 45-C can, as needed, select any single wavelength from the C-band wavelength range as a specific wavelength for the input C-band optical signal 53-C. The C-band optical signal 54-C of the specific wavelength selected by the wavelength selection switch 45-C is output to a specific output port selected from among the B output ports.

[0052] The wavelength band converter 46 performs a single wavelength band conversion from C-band to L-band for any C-band optical signal 54-C of any wavelength input from a specific output port of the wavelength selection switch 45-C. Therefore, an L-band optical signal 55-L is output from the wavelength band converter 46.

[0053] The optical multiplexer 47 outputs a wavelength-converted output optical signal 49, which is the result of combining the C-band optical signal 54-C output by the wavelength selector switch 45-C to a specific output port and the L-band optical signal 55-L output by the wavelength band converter 46. Therefore, the wavelength-converted output optical signal 49 can correspond to an ultra-broadband optical signal including the C-band and L-band.

[0054] In the wavelength conversion device 103 shown in Figure 7, the wavelength selector switch 45-C is composed of an optical device that supports only single bands. Therefore, the wavelength selector switch 45-C has high wavelength resolution. For example, as shown in the example in Figure 3, optical signals with wavelengths λ1 to λ7 can be distinguished for each wavelength channel with a wavelength resolution equivalent to F1 and output to output ports in different directions.

[0055] Furthermore, for example, if the wavelength converter 103 shown in Figure 7 is configured to support only wavelength bands B4 and B5, it is possible to expand the supported bandwidth to wavelength bands B1 to B6. In that case, the optical devices in the wavelength selection switch 45-C and the wavelength converter 44-C within the wavelength converter 103 do not need to be replaced; the bandwidth expansion can be accommodated simply by adding the missing optical devices.

[0056] The wavelength converter 103 has the function of allowing the wavelength bandwidth of the input and / or output light to encompass multiple wavelength bands and outputting an optical signal of a desired wavelength converted for each wavelength of the input optical signal. Furthermore, the wavelength converter 103 has the function of allowing the input of a single-wavelength optical signal whose wavelength falls within a specific wavelength band or any wavelength band, and allowing the selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0057] <Configuration Example 4> Figure 8 shows Configuration Example 4 of the wavelength conversion device according to an embodiment of the present invention. The wavelength conversion device 104 shown in Figure 8 has the function of allowing input of a single-band WDM (Wavelength Division Multiplexing) optical signal 67 as the target for processing, and has the function of converting any input WDM optical signal to a desired wavelength. The wavelength-converted output optical signal 68 becomes an ultra-broadband WDM optical signal that includes multiple wavelength bands.

[0058] Furthermore, the example in Figure 8 assumes that the input WDM optical signal 67 is in the C-band wavelength range, and that the output optical signal 68, which is wavelength-converted, contains a WDM optical signal that includes both the C-band and L-band wavelength ranges.

[0059] The wavelength conversion device 104 in Figure 8 comprises a wavelength selection switch 61-C, a wavelength band converter 62, wavelength selection switches 63-C and 63-L, wavelength conversion units 64-C and 64-L, and a multiplexer (optical multiplexer) 66. The wavelength conversion unit 64-C has M wavelength converters 65-C corresponding to the number of wavelengths M that can be converted simultaneously. Similarly, the wavelength conversion unit 64-L has M wavelength converters 65-L.

[0060] Here, the wavelength selector switches 61-C, 63-C, the wavelength conversion unit 64-C, and each of the M wavelength converters 65-C are configured as single-band optical devices corresponding only to the C-band wavelength range. In addition, the wavelength selector switch 63-L, the wavelength conversion unit 64-L, and each of the M wavelength converters 65-L are configured as single-band optical devices corresponding only to the L-band wavelength range.

[0061] Furthermore, the wavelength selector switch 61-C has one input port and multiple output ports equal to the number of corresponding bands (B). The two wavelength selector switches 63-C and 63-L each have one input port and multiple M output ports. The wavelength band converter 62 has the function of converting WDM optical signals in the C-band wavelength range into WDM optical signals in the L-band wavelength range.

[0062] The operation of the wavelength converter 104 shown in Figure 8 will be described below. The wavelength selection switch 61-C can receive any WDM optical signal 67 in the C-band wavelength range and select a WDM optical signal for each converted wavelength band. The wavelength selection switch 61-C outputs the selected WDM optical signal to a specific output port among the B output ports.

[0063] The converted WDM optical signal, whose wavelength band is C-band, is input to wavelength selector switch 63-C from a specific output port of wavelength selector switch 61-C. Wavelength selector switch 63-C selects the input WDM optical signal 69 wavelength by wavelength and outputs the selected wavelength to a specific port among its M output ports.

[0064] The optical signals of each wavelength output from the M output ports of the wavelength selection switch 63-C are input to the M wavelength converters 65-C in the wavelength conversion unit 64-C and converted to their respective wavelengths. The M wavelengths of the C-band optical signals output by the wavelength conversion unit 64-C are then input to the multiplexer 66.

[0065] On the other hand, the converted WDM optical signal with a wavelength band in the L band is input to the wavelength band converter 62 from a specific output port of the wavelength selection switch 61-C. The wavelength band converter 62 converts the wavelength band of the input C band WDM optical signal 69 from C band to L band all at once. The L band WDM optical signal output by the wavelength band converter 62 is input to the wavelength selection switch 63-L. The wavelength selection switch 63-L selects the L band WDM optical signal output from the wavelength band converter 62 wavelength by wavelength and outputs the selected wavelength to a specific port among the M output ports.

[0066] The optical signals of each wavelength output from the M output ports of the wavelength selection switch 63-L are input to the M wavelength converters 65-L in the wavelength conversion unit 64-L and converted to their respective wavelengths. The M wavelengths of the L-band optical signals output by the wavelength conversion unit 64-L are then input to the multiplexer 66.

[0067] The multiplexer 66 receives optical signals of multiple wavelengths in the C-band from the wavelength conversion unit 64-C, and optical signals of multiple wavelengths in the L-band from the wavelength conversion unit 64-L. The multiplexer 66 then outputs the combined output optical signal 68 as a wavelength-converted signal. Therefore, this output optical signal 68 becomes a broadband WDM optical signal spanning multiple wavelength bands.

[0068] The wavelength conversion device 104 has the function of accepting as input optical signals wavelength-division multiplexed within a specific wavelength band or any wavelength band, and allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0069] <Configuration Example 5> Figure 9 shows a configuration example 5 of the wavelength conversion device according to an embodiment of the present invention. The wavelength conversion device 105 shown in Figure 9, like the wavelength conversion device 104 in Figure 8, has the function of accepting a single-band WDM (Wavelength Division Multiplexing) optical signal 77-C as input to be processed, and has the function of converting any input WDM optical signal to a desired wavelength. The wavelength-converted output optical signal 78 becomes an ultra-broadband WDM optical signal that includes multiple wavelength bands.

[0070] Furthermore, in the example shown in Figure 9, it is assumed that the input WDM optical signal 77-C is in the C-band wavelength range, and the output optical signal 78, which is wavelength-converted, contains a WDM optical signal that includes both the C-band and L-band wavelength ranges.

[0071] The wavelength conversion device 105 in Figure 9 comprises wavelength selection switches 71-C and 74-C, a wavelength conversion unit 72-C, a wavelength band converter 75, and a multiplexer (optical multiplexer) 76. The wavelength conversion unit 72-C also has M wavelength converters 73-C, corresponding to the number of wavelengths M that can be converted simultaneously.

[0072] Here, the wavelength selection switches 71-C, 74-C, the wavelength conversion unit 72-C, and each of the M wavelength converters 73-C are configured as single-band optical devices corresponding only to the C-band wavelength range.

[0073] Furthermore, the wavelength selector switch 71-C has one input port and a plurality of M output ports. The wavelength selector switch 74-C has M input ports and a plurality of output ports equal to the number of corresponding bands (B). In addition, the wavelength band converter 75 has the function of converting WDM optical signals in the C-band wavelength range into WDM optical signals in the L-band wavelength range all at once.

[0074] In the configuration of the wavelength conversion device 105 shown in Figure 9, the wavelength band converter 75 is located downstream of the wavelength conversion unit 72-C. This configuration eliminates the need to provide a separate wavelength conversion unit 72-C for each band, thereby reducing the number of optical device elements that make up the wavelength conversion device 105.

[0075] The operation of the wavelength conversion device 105 shown in Figure 9 will be described below. The wavelength selection switch 71-C receives an arbitrary WDM optical signal 77-C in the C-band wavelength range and can individually select each of the multiple wavelengths contained in the WDM optical signal. It then outputs the optical signal of the selected wavelength to a specific output port among the M output ports. Therefore, the input WDM optical signal 77-C is output from the wavelength selection switch 71-C in a state separated by wavelength and input to the wavelength conversion unit 72-C.

[0076] The wavelength conversion unit 72-C uses M wavelength converters 73-C to perform wavelength conversion within the C-band for each wavelength of the WDM optical signal. The C-band WDM optical signals converted by the wavelength conversion unit 72-C are input to the respective wavelength selection switches 74-C.

[0077] The wavelength selector switch 74-C can select WDM optical signals separately for each band after wavelength band conversion. The wavelength selector switch 74-C outputs the selected WDM optical signal to the output port corresponding to the band among the multiple B output ports.

[0078] WDM optical signals that do not require wavelength band conversion are output from a specific output port of the wavelength selector switch 74-C and input to the multiplexer 76 as a C-band optical signal 79-C. WDM optical signals that require wavelength band conversion are output from a specific output port of the wavelength selector switch 74-C and input to the wavelength band converter 75.

[0079] The wavelength band converter 75 converts the C-band optical signal input from the wavelength selector switch 74-C in the form of a WDM optical signal to generate an L-band optical signal 79-L. The multiplexer 76 combines the C-band optical signal 79-C output from the wavelength selector switch 74-C and the L-band optical signal 79-L output from the wavelength band converter 75 to generate a wavelength-converted output optical signal 78. Therefore, a broadband WDM optical signal including both the C-band and L-band can be output as a wavelength-converted output optical signal 78.

[0080] The wavelength conversion device 104 with the configuration shown in Figure 8 requires independent wavelength conversion units 64-C and 64-L for each band, but the wavelength conversion device 105 with the configuration shown in Figure 9 requires only one wavelength conversion unit 72-C corresponding to one band, and does not require a wavelength conversion unit for the L band.

[0081] The wavelength conversion device 105 has the function of accepting as input optical signals wavelength-division multiplexed within a specific wavelength band or any wavelength band, and allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0082] <Configuration Example 6> Figure 10 shows a configuration example 6 of the wavelength conversion device according to an embodiment of the present invention. In the configurations shown in Figures 8 and 9 above, the input of a WDM optical signal 67 is permitted, but this WDM optical signal 67 is limited to cases where all the wavelengths contained therein are within a single band. On the other hand, the wavelength conversion device 106 shown in Figure 10 has the function of allowing the input of a WDM optical signal 87 spanning multiple bands as the target of processing, and has the function of converting any input WDM optical signal to a desired wavelength. The wavelength-converted output optical signal 88 becomes an ultra-broadband WDM optical signal that includes multiple wavelength bands.

[0083] Furthermore, the example in Figure 10 assumes that multiple wavelengths included in the input WDM optical signal 87 span both the C-band and L-band wavelength bands, and that the WDM optical signal containing both the C-band and L-band wavelength bands is included in the wavelength-converted output optical signal 88.

[0084] The wavelength conversion device 106 in Figure 10 comprises a demultiplexer 81, wavelength selector switches 82-C and 82-L, wavelength band converters 83-1 and 83-2, wavelength selector switches 84-C and 84-L, wavelength conversion units 85-C and 85-L, and a multiplexer 86. Each of the wavelength conversion units 85-C and 85-L contains M wavelength converters corresponding to the number of wavelengths M that can be converted simultaneously.

[0085] Here, the wavelength selector switch 82-C, the wavelength selector switch 84-C, and the wavelength conversion unit 85-C are each configured as single-band optical devices corresponding only to the C-band wavelength range. In addition, the wavelength selector switch 82-L, the wavelength selector switch 84-L, and the wavelength conversion unit 85-L are each configured as single-band optical devices corresponding only to the L-band wavelength range.

[0086] Furthermore, the wavelength band converter 83-1 has the function of converting wavelengths from the L-band wavelength band to the C-band wavelength band all at once, and the wavelength band converter 83-2 has the function of converting wavelengths from the C-band wavelength band to the L-band wavelength band all at once.

[0087] Furthermore, the wavelength selector switches 82-C and 82-L have one input port and B output ports corresponding to the number of bands B. The wavelength selector switches 84-C and 84-L have multiple input ports equal to the number of bands B and M output ports corresponding to the number of wavelengths M that can be converted simultaneously.

[0088] The operation of the wavelength converter 106 in Figure 10 will be described below. The WDM optical signal 87, which spans multiple bands, is split into a C-band optical signal 87-C and an L-band optical signal 87-L by the demultiplexer 81, and output from different ports for each band.

[0089] Wavelength selector switch 82-C receives a C-band optical signal 87-C containing the C-band wavelength range and individually selects each of the multiple wavelengths contained in this optical signal. Then, wavelength selector switch 82-C outputs the optical signals of the selected wavelengths to specific output ports that differ for each band after wavelength band conversion. Among the wavelengths selected by wavelength selector switch 82-C, optical signals whose wavelength range remains within the C-band after wavelength band conversion are input from the output of wavelength selector switch 82-C to wavelength selector switch 84-C. Also, among the wavelengths selected by wavelength selector switch 82-C, optical signals whose wavelength range after wavelength band conversion becomes the L-band are input from the output of wavelength selector switch 82-C to wavelength band converter 83-2.

[0090] Wavelength selector switch 82-L receives an L-band optical signal 87-L containing the L-band wavelength range and individually selects each of the multiple wavelengths contained in this L-band optical signal 87-L. Wavelength selector switch 82-L then outputs the optical signals of the selected wavelengths to specific output ports that differ for each band after wavelength band conversion. Among the wavelengths selected by wavelength selector switch 82-L, optical signals whose wavelength range remains within the L-band after wavelength band conversion are input from the output of wavelength selector switch 82-L to wavelength selector switch 84-L. In addition, among the wavelengths selected by wavelength selector switch 82-L, optical signals whose wavelength range after wavelength band conversion becomes the C-band are input from the output of wavelength selector switch 82-C to wavelength band converter 83-1.

[0091] Wavelength band converter 83-1 converts the L-band optical signal output from wavelength selector switch 82-L to generate a C-band optical signal. Wavelength band converter 83-2 converts the C-band optical signal output from wavelength selector switch 82-C to generate an L-band optical signal.

[0092] The wavelength selection switch 84-C receives a WDM optical signal whose wavelength band after wavelength band conversion is within the C band, and selects an optical signal for each wavelength from this WDM optical signal. The optical signal of each wavelength selected by the wavelength selection switch 84-C is output from a specific output port among the M output ports that corresponds to that wavelength, and is input to each wavelength converter in the wavelength conversion unit 85-C for each wavelength.

[0093] The wavelength selection switch 84-L receives a WDM optical signal whose wavelength band after wavelength band conversion is within the L band, and selects an optical signal for each wavelength from this WDM optical signal. The optical signal of each wavelength selected by the wavelength selection switch 84-L is output from a specific output port among the M output ports that corresponds to that wavelength, and is input to each wavelength converter in the wavelength conversion unit 85-L for each wavelength.

[0094] The wavelength conversion unit 85-C uses its built-in M wavelength converters to perform wavelength conversion of the WDM optical signal within the C-band bandwidth for each wavelength. The C-band WDM optical signals converted by the wavelength conversion unit 85-C are then input to the multiplexer 86 for each wavelength.

[0095] The wavelength conversion unit 85-L uses its built-in M wavelength converters to perform wavelength conversion within the L-band bandwidth for each wavelength of the WDM optical signal. The L-band WDM optical signals converted by the wavelength conversion unit 85-L are then input to the multiplexer 86 for each wavelength.

[0096] The multiplexer 86 outputs a wavelength-converted output optical signal 88, which is the result of combining the C-band WDM optical signal output from the wavelength conversion unit 85-C and the L-band WDM optical signal output from the wavelength conversion unit 85-L. Therefore, the wavelength-converted output optical signal 88 can handle a wideband WDM optical signal that spans both the C-band and L-band.

[0097] The wavelength conversion device 106 accepts an optical signal as input that is wavelength-division multiplexed across multiple wavelength bands, and has the function of allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0098] <Configuration Example 7> Figure 11 shows a configuration example 7 of the wavelength conversion device according to an embodiment of the present invention. The wavelength conversion device 107 shown in Figure 11 has the same functions as the wavelength conversion device 106 in Figure 10 and includes almost the same components as the wavelength conversion device 106. However, in the configuration of Figure 10, the wavelength band converters 83-1 and 83-2 are located upstream of the wavelength conversion units 85-C and 85-L, while in the configuration of Figure 11, the wavelength band converters 83-1 and 83-2 are located downstream of the wavelength conversion units 85-C and 85-L.

[0099] Wavelength selector switches 82-C and 82-L in Figure 11 have one input port and M output ports corresponding to the number of wavelengths M that are converted simultaneously. Wavelength selector switches 84-C and 84-L in Figure 11 have one input port and multiple output ports equal to the number of bands B.

[0100] The operation of the wavelength converter 107 in Figure 11 will be described below. The WDM optical signal 87, which spans multiple bands, is split into a C-band optical signal 87-C and an L-band optical signal 87-L by the demultiplexer 81, and output from different ports for each band.

[0101] The wavelength selection switch 82-C receives a C-band optical signal 87-C that includes the C-band wavelength range and individually selects each of the multiple wavelengths contained in this optical signal. Then, the wavelength selection switch 82-C outputs the optical signal of the selected wavelength to a specific output port among the M output ports that corresponds to that wavelength.

[0102] The wavelength selection switch 82-L receives an L-band optical signal 87-L that includes the L-band wavelength range and individually selects each of the multiple wavelengths contained in this optical signal. Then, the wavelength selection switch 82-L outputs the optical signal of the selected wavelength to a specific output port among the M output ports that corresponds to that wavelength.

[0103] The C-band optical signals output by the wavelength selection switch 82-C for each wavelength are converted to different wavelengths within the same band by the wavelength converters built into the wavelength conversion unit 85-C. Similarly, the L-band optical signals output by the wavelength selection switch 82-L for each wavelength are converted to different wavelengths within the same band by the wavelength converters built into the wavelength conversion unit 85-L.

[0104] The wavelength selection switch 84-C receives a WDM optical signal within the C-band bandwidth output by the wavelength conversion unit 85-C and outputs it from a specific output port associated with the corresponding band after wavelength band conversion.

[0105] The C-band WDM optical signal, which changes to the L-band wavelength range after wavelength band conversion, is input to the wavelength band converter 83-1 from the corresponding output port of the wavelength selection switch 84-C. The wavelength band converter 83-1 converts the wavelength range of the input C-band WDM optical signal from the C-band to the L-band in one go. The WDM optical signal that remains in the C-band wavelength range after wavelength band conversion is input to the multiplexer 86 from the corresponding output port of the wavelength selection switch 84-C.

[0106] The wavelength selection switch 84-L receives a WDM optical signal within the L-band bandwidth output by the wavelength conversion unit 85-L and outputs it from a specific output port associated with the corresponding band after wavelength band conversion.

[0107] The L-band WDM optical signal, which changes to the C-band wavelength band after wavelength band conversion, is input to the wavelength band converter 83-2 from the corresponding output port of the wavelength selection switch 84-L. The wavelength band converter 83-2 converts the wavelength band of the input L-band WDM optical signal from the L-band to the C-band in one go. The WDM optical signal that remains in the L-band wavelength band after wavelength band conversion is input to the multiplexer 86 from the corresponding output port of the wavelength selection switch 84-L.

[0108] The wavelength converter 107's multiplexer 86 combines the L-band WDM optical signal output from the wavelength band converter 83-1, the C-band WDM optical signal output from the wavelength selection switch 84-C, the C-band WDM optical signal output from the wavelength band converter 83-2, and the L-band WDM optical signal output from the wavelength selection switch 84-L. The result is output as the wavelength-converted output optical signal 88. Therefore, the wavelength-converted output optical signal 88 can handle a wideband WDM optical signal spanning both the C-band and L-band.

[0109] The wavelength conversion device 107 accepts an optical signal as input that is wavelength-division multiplexed across multiple wavelength bands, and has the function of allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0110] <Configuration Example 8> Figure 12 shows Configuration Example 8 of the wavelength conversion device according to an embodiment of the present invention. The wavelength conversion device 108 shown in Figure 12 has the function of accepting input of WDM optical signals 98 spanning multiple bands as the target of processing, similar to the configurations shown in Figures 10 and 11, and has the function of converting any input WDM optical signal to a desired wavelength for each wavelength. The output optical signal 99 after wavelength conversion becomes an ultra-broadband WDM optical signal including multiple wavelength bands.

[0111] On the other hand, in the configurations shown in Figures 10 and 11, wavelength conversion units 85-C and 85-L corresponding to each of the multiple wavelength bands are required. However, in the configuration of the wavelength conversion device 108 in Figure 12, the wavelength conversion units 94-1 and 94-2 can be composed only of optical devices corresponding to the same wavelength band.

[0112] In the example shown in Figure 12, it is assumed that multiple wavelengths included in the input WDM optical signal 98 span both the C-band and L-band wavelength bands, and that the WDM optical signal including both the C-band and L-band wavelength bands is included in the output optical signal 99 after wavelength conversion.

[0113] The wavelength conversion device 108 shown in Figure 12 comprises a demultiplexer 91, a wavelength band converter 92, wavelength selection switches 93-1 and 93-2, wavelength conversion units 94-1 and 94-2, a wavelength selection switch 95, a wavelength band converter 96, and a multiplexer 97. Furthermore, the wavelength conversion units 94-1 and 94-2 each contain M wavelength converters, the same number as the number of wavelengths M that can be converted simultaneously.

[0114] Here, the wavelength selection switches 93-1, 93-2, and 95, and the wavelength conversion units 94-1 and 94-2 are each configured as single-band optical devices corresponding only to the C-band wavelength range. The same applies to the wavelength converters built into each of the wavelength conversion units 94-1 and 94-2. Furthermore, the wavelength band converter 92 has the function of taking a WDM optical signal in the L-band wavelength range and converting it to the C-band wavelength range all at once for each wavelength. Furthermore, the wavelength band converter 96 has the function of taking a WDM optical signal in the C-band wavelength range and converting it to a WDM optical signal in the L-band wavelength range all at once for each wavelength.

[0115] Each wavelength selector switch 93-1 and 93-2 has one input port and M output ports, which are equal to the number of wavelengths M that can be converted simultaneously. Wavelength selector switch 95 has M input ports, which are equal to the number of wavelengths M, and B output ports, which are equal to the number of corresponding bands B.

[0116] The operation of the wavelength converter 108 in Figure 12 will be described below. The WDM optical signal 98, which spans multiple bands, is split into a C-band optical signal 98-C and an L-band optical signal 98-L by the demultiplexer 91, and output from different ports for each band.

[0117] Of the WDM optical signals output from the demultiplexer 91, the C-band optical signal 98-C is input to the wavelength selector switch 93-1. The L-band optical signal 98-L is input to the wavelength band converter 92. The wavelength band converter 92 converts the wavelength band of the input L-band optical signal 98-L from the L-band to the C-band all at once. The C-band optical signal output by the wavelength band converter 92 is input to the wavelength selector switch 93-2.

[0118] The wavelength selection switch 93-1 receives the C-band optical signal 98-C as input and individually selects each of the multiple wavelengths contained in this optical signal. Then, the wavelength selection switch 93-1 outputs the optical signal of each selected wavelength to a specific output port among the M output ports that corresponds to that wavelength.

[0119] Similarly, the wavelength selection switch 93-2 receives the C-band optical signal from the output of the wavelength band converter 92 and individually selects each of the multiple wavelengths contained in this optical signal. The wavelength selection switch 93-2 then outputs the optical signal of each selected wavelength to a specific output port among the M output ports that corresponds to that wavelength.

[0120] The C-band optical signals output by the wavelength selection switch 93-1 for each wavelength are input to the wavelength conversion unit 94-1 and converted to different wavelengths within the same band for each wavelength. Similarly, the C-band optical signals output by the wavelength selection switch 93-2 for each wavelength are input to the wavelength conversion unit 94-2 and converted to different wavelengths within the same band for each wavelength.

[0121] The wavelength selection switch 95 receives optical signals in the C-band wavelength range from the outputs of the wavelength conversion units 94-1 and 94-2 for each wavelength, and distinguishes and selects multiple optical signals for each converted wavelength range. The wavelength selection switch 95 then outputs the optical signal of the selected wavelength range to a specific output port among the B output ports that corresponds to that wavelength range.

[0122] The optical signals of each wavelength in the converted C-band are input to the multiplexer 97 from the output of the wavelength selector switch 95 as C-band optical signals 99-C. The optical signals of each wavelength in the converted L-band are input to the wavelength band converter 96 from the output of the wavelength selector switch 95. The wavelength band converter 96 converts the wavelengths of the optical signals of each wavelength input from the output of the wavelength selector switch 95 from the C-band to the L-band all at once and outputs them as L-band optical signals 99-L.

[0123] The wavelength converter 108's multiplexer 97 combines the C-band optical signal 99-C output from the wavelength selection switch 95 and the L-band optical signal 99-L output from the wavelength band converter 96, and outputs a wavelength-converted output optical signal 99. Therefore, the wavelength converter 108 can handle a wideband WDM optical signal spanning both the C-band and L-band as the wavelength-converted output optical signal 99.

[0124] The wavelength conversion device 108 accepts an optical signal as input that is wavelength-division multiplexed across multiple wavelength bands, and has the function of allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

[0125] <Configuration Example 9> Figure 13 shows a configuration example 9 of the wavelength conversion device according to an embodiment of the present invention. The wavelength conversion device 109 shown in Figure 13, like the wavelength conversion device 108 shown in Figure 12, has the function of accepting input of WDM optical signals 98 spanning multiple bands as the target for processing, and has the function of converting any input WDM optical signal to a desired wavelength for each wavelength. The output optical signal 99 after wavelength conversion becomes an ultra-broadband WDM optical signal including multiple wavelength bands.

[0126] On the other hand, in the configuration shown in Figure 12, two sets of wavelength conversion units 94-1 and 94-2 are required to convert the C-band optical signal 98-C and the L-band optical signal 98-L contained in the WDM optical signal 98 wavelength by wavelength. In the configuration of the wavelength conversion device 109 shown in Figure 13, one set of wavelength conversion units 94 can be shared for wavelength conversion of both the C-band optical signal 98-C and the L-band optical signal 98-L. Therefore, the number of optical device elements constituting the wavelength conversion device 109 can be reduced compared to the configuration in Figure 12.

[0127] The wavelength conversion device 109 shown in Figure 13 comprises a demultiplexer (demultiplexer)

[0128] The first optical coupler 111-1 receives the first wavelength selected by the wavelength selection switch 93-1 and the first wavelength selected by the wavelength selection switch 93-2 from among the optical signals of each wavelength included in the C-band WDM optical signal, and superimposes the result, which is then fed to the first wavelength converter in the wavelength conversion unit 94.

[0129] Similarly to the above, the nth optical coupler 111-n inputs the nth wavelength selected by the wavelength selection switch 93-1 and the nth wavelength selected by the wavelength selection switch 93-2 from among the optical signals of each wavelength included in the C-band WDM optical signal, and the result of superimposing them is fed to the nth wavelength converter in the wavelength conversion unit 94.

[0130] Each wavelength converter in the wavelength conversion unit 94 converts the wavelength of the input optical signal to a different desired wavelength within the C-band bandwidth and outputs it. The wavelength selection switch 95 takes optical signals in the C-band wavelength range as input from the output of the wavelength conversion unit 94 for each wavelength, and distinguishes and selects multiple optical signals for each converted wavelength band. The wavelength selection switch 95 then outputs the optical signal of the selected wavelength band to a specific output port among the B output ports that corresponds to that wavelength band. The operation of the wavelength conversion device 109 other than that described above is the same as that of the wavelength conversion device 108 in Figure 12.

[0131] <Configuration Example 10> Figure 14 shows an example configuration 10 of the control mechanism and wavelength converter in an embodiment of the present invention. Figures 15 to 20 also show examples of the operation sequence of the system including the wavelength converter. The wavelength converter 100 shown in Figure 14 incorporates one or more wavelength selection switches 100a and one or more wavelength converters 100b, similar to the wavelength converters 101 to 109 described above. In the configuration of Figure 14, a control mechanism 120 is connected to the wavelength converter 100 in order to control the wavelength selection switches 100a and the wavelength converters 100b. The control mechanism 120 can control the wavelength selection switches 100a and the wavelength converters 100b, for example, as shown in Figures 15 to 20.

[0132] <Operation Example 1> Operation Example 1 shown in Figure 15 will be explained below. For example, when a need for an optical path arises, the administrator initiates a search for available paths and wavelengths on the network to set up the optical path, either through manual operation or by instruction from the higher-level computer 200 that manages optical communication. In the example in Figure 15, the higher-level computer 200 first performs an "optical path search - 1" in step S11, which is a search without wavelength conversion. If path design is impossible under these conditions, the higher-level computer 200 performs an "optical path search - 2" in step S12, which is a search with wavelength conversion. Based on the results of the above search, the higher-level computer 200 determines in step S13 whether or not to use the wavelength conversion device 100, which includes characteristic elements of the present invention, for setting up the optical path. If it is determined that the wavelength conversion device 100 should be used, the higher-level computer 200 gives the control mechanism 120 the instructions necessary for the wavelength conversion operation of the wavelength conversion device 100 in step S14.

[0133] In step S21, the control mechanism 120 selects the optical device to be used for the wavelength conversion from one or more usable wavelength band converters (AO-WC), one or more wavelength converters 100b, and one or more wavelength selection switches 100a that are actually installed in the wavelength conversion device 100. In step S22, the control mechanism 120 determines the control parameters for each optical device actually used on the wavelength conversion device 100 according to the requested wavelength conversion status. For example, it determines the control parameters for the wavelength converter 100b to match the wavelengths before and after the wavelength conversion. For example, in the case of an all-optical type wavelength converter, it is necessary to adjust the excitation light according to the wavelength. Also, for the wavelength selection switch 100a, it is necessary to select a specific output port according to the wavelength of the input optical signal. In step S23, the control mechanism 120 instructs the wavelength selection switch 100a and wavelength converter 100b in the wavelength conversion device 100 to update their status according to the control parameters determined in step S22. The wavelength selection switch 100a and the wavelength converter 100b within the wavelength conversion device 100 update their respective control parameters in step S31 according to instructions from the control mechanism 120.

[0134] <Operation Example 2> Operation Example 2 shown in Figure 16 will be explained below. This Operation Example 2 is a modified version of "Operation Example 1" described above. In the example in Figure 16, the higher-level computer 200 first performs "Optical Path Search 3" in step S11A. In this "Optical Path Search 3", searches are performed both under conditions where wavelength conversion is not performed and under conditions where wavelength conversion is performed. Based on the above search results, the higher-level computer 200 determines in step S13 whether or not to use the wavelength conversion device 100, which includes characteristic elements of the present invention, in the optical path setting. If it is determined that the wavelength conversion device 100 should be used, the higher-level computer 200 gives the control mechanism 120 instructions necessary for the wavelength conversion operation of the wavelength conversion device 100 in step S14. The contents of "Operation Example 2" other than those described above are the same as in the case of "Operation Example 1" described above.

[0135] <Operation Example 3> Operation Example 3 shown in Figure 17 will be explained below. This Operation Example 3 is a modified version of "Operation Example 1" described above. In the example in Figure 17, the higher-level computer 200 first performs an "optical path search - 1" in step S11, which is a search for a case where wavelength conversion is not performed. If path design is not possible under those conditions, the higher-level computer 200 performs an "optical path search - 2" in step S12, which is a search for a case where wavelength conversion is performed. Based on the results of the above search, the higher-level computer 200 determines in step S13 whether or not to use the wavelength conversion device 100, which includes characteristic elements of the present invention, in the optical path setting. If it is determined that the wavelength conversion device 100 should be used, the higher-level computer 200 performs the processing from step S41 onwards. In step S41, the higher-level computer 200 selects the optical device to be used for this wavelength conversion from one or more usable wavelength band converters (AO-WC), one or more wavelength converters 100b, and one or more wavelength selection switches 100a that are actually equipped in the wavelength conversion device 100. In step S42, the higher-level computer 200 determines the control parameters for each optical device actually used on the wavelength conversion device 100 according to the requested wavelength conversion status. For example, it determines the control parameters for the wavelength converter 100b to match the wavelengths before and after wavelength conversion. For example, in the case of an all-optical type wavelength converter, it is necessary to adjust the excitation light according to the wavelength. Also, for the wavelength selection switch 100a, it is necessary to select a specific output port according to the wavelength of the input optical signal. In step S43, the higher-level computer 200 gives instructions to the control mechanism 120 regarding the control content determined in steps S41 and S42. In step S23A, the control mechanism 120 instructs the wavelength selection switch 100a and the wavelength converter 100b within the wavelength conversion device 100 to update the state of the instructed control parameters according to the instructions from the higher-level computer 200. The wavelength selection switch 100a and the wavelength converter 100b within the wavelength conversion device 100 each update their own control parameters in step S31 according to the instructions from the control mechanism 120.

[0136] <Operation Example 4> Operation Example 4 shown in Figure 18 will be explained below. This Operation Example 4 is a modified version of "Operation Example 3" described above. In the example in Figure 18, the higher-level computer 200 first performs "Optical Path Search 3" in step S11A. In this "Optical Path Search 3", searches are performed both under conditions where wavelength conversion is not performed and under conditions where wavelength conversion is performed. Based on the above search results, the higher-level computer 200 determines in step S13 whether or not to use the wavelength conversion device 100, which includes characteristic elements of the present invention, in the optical path setting. If it is determined that the wavelength conversion device 100 should be used, the higher-level computer 200 gives the control mechanism 120 instructions necessary for the wavelength conversion operation of the wavelength conversion device 100 in step S14. The contents of "Operation Example 4" other than those described above are the same as in the case of "Operation Example 3" described above.

[0137] <Operation Example 5> Operation Example 5 shown in Figure 19 will be explained below. This Operation Example 5 is a modified version of "Operation Example 1" described above. In the example in Figure 19, the higher-level computer 200 first performs an optical path search in step S11, which is called "Optical Path Search 1," in the case where wavelength conversion is not performed. If path design is not possible under these conditions, the higher-level computer 200 proceeds to step S52, where it checks the current state (status) of the wavelength selection switch 100a and wavelength converter 100b in the available wavelength conversion device 100. The control mechanism 120 constantly manages status information representing the state of the wavelength selection switch 100a and wavelength converter 100b in the wavelength conversion device 100 connected under its control. Then, in response to an inquiry from the higher-level computer 200, the control mechanism 120 reports the status information of the wavelength selection switch 100a and wavelength converter 100b in step S51. In step S12, the higher-level computer 200 performs an optical path search in the case where wavelength conversion is performed, which is called "Optical Path Search 2." In this search, the status information of the wavelength selection switch 100a and wavelength converter 100b confirmed in step S52 is used. Based on the results of the above search, the higher-level computer 200 determines in step S13 whether or not to use the wavelength conversion device 100, which includes the characteristic elements of the present invention, in the optical path setting. If it is determined that the wavelength conversion device 100 should be used, the higher-level computer 200 gives the control mechanism 120 instructions necessary for the wavelength conversion operation of the wavelength conversion device 100 in step S14. The contents of "Operation Example 5" other than those described above are the same as in the case of "Operation Example 1". <Operation Example 6> Operation Example 6 shown in Figure 20 will be described below. This Operation Example 6 is a modified version of "Operation Example 1". In the example in Figure 20, the higher-level computer 200 first checks the current state (status) of the wavelength selection switch 100a and wavelength converter 100b in the available wavelength conversion device 100 in step S52. The control mechanism 120 constantly manages status information representing the state of the wavelength selection switch 100a and the wavelength converter 100b in the wavelength conversion device 100 connected under its control.Then, in response to an inquiry from the higher-level computer 200, the control mechanism 120 reports the status information of the wavelength selection switch 100a and the wavelength converter 100b in step S51. The higher-level computer 200 performs "Optical Path Search - 3" in step S11A. In this "Optical Path Search - 3," searches are performed both under conditions where wavelength conversion is not performed and under conditions where wavelength conversion is performed. When performing a search under conditions where wavelength conversion is performed, the status information of the wavelength selection switch 100a and the wavelength converter 100b confirmed in step S52 is used. Based on the above search results, the higher-level computer 200 determines in step S13 whether or not to use the wavelength conversion device 100, which includes the characteristic elements of the present invention, in the optical path setting. If it is determined that the wavelength conversion device 100 should be used, the higher-level computer 200 gives the control mechanism 120 the instructions necessary for the wavelength conversion operation of the wavelength conversion device 100 in step S14. The contents of "Operation Example - 6" other than those described above are the same as in "Operation Example - 1".

[0138] <Features of the Invention> The following are characteristic features of the wavelength conversion device of the present invention: [1] A wavelength conversion device comprising: one or more wavelength selection switches (21-C, etc.) having the function of outputting an input optical signal in any direction for each wavelength; one or more wavelength band converters (22) having the function of collectively converting the wavelength of the input optical signal to a wavelength in a different wavelength band determined for each wavelength; one or more wavelength converters (23-C) having the function of converting the wavelength of the input optical signal to a different wavelength within the same wavelength band than the input; and one or more multiplexers (24, etc.) having the function of combining a plurality of optical signals with different wavelength bands from each other, wherein the wavelength bandwidth of the wavelengths of the input light (input optical signal 25, etc.) and / or output light (output optical signal 28, etc.) includes a plurality of wavelength bands (B4, B5, etc.), and has the function of outputting an optical signal of a desired wavelength converted for each wavelength of the input optical signal.

[0139] According to the wavelength conversion device with the configuration described in [1] above, wavelength conversion of an optical signal can be performed by combining a wavelength band converter with a wide wavelength conversion range and a wavelength converter with a narrow wavelength conversion range. Therefore, even when dealing with ultra-broadband optical signals, optical devices that support only single bands can be used as the wavelength selection switch and the wavelength converter. Since optical devices that support only single bands have high wavelength resolution, the wavelength selection switch can separate the input optical signal for each wavelength channel and output each in the desired direction. Furthermore, when extending the range of corresponding wavelength conversion to a wider bandwidth, it becomes unnecessary to replace the existing optical device with another device.

[0140] [2] The wavelength conversion device described in [1] above, which has the function of allowing input of a single-wavelength optical signal (input optical signal 25-C, etc.) whose wavelength is within a specific wavelength band or an arbitrary wavelength band as the input optical signal, and allowing selective output of multiple wavelength optical signals (output optical signal 28, etc.) whose wavelength bands are different from each other.

[0141] According to the wavelength conversion device with the configuration described in [2] above, an optical signal of any wavelength can be input, and an optical signal of any wavelength different from the input wavelength can be output over a wide bandwidth of wavelengths. Moreover, since an optical device with high wavelength resolution can be used as the wavelength selection switch, the input optical signal can be separated for each wavelength channel and output in the desired direction. Furthermore, when extending the range of the corresponding wavelength conversion to a wider bandwidth, there is no need to replace the existing optical device with another device with different wavelength characteristics.

[0142] [3] The wavelength conversion device described in [1] above, which allows input of an optical signal that has been wavelength-division multiplexed within a specific wavelength band or an arbitrary wavelength band (such as a single-band WDM optical signal 67), and has the function of allowing selective output of optical signals of multiple wavelengths having different wavelength bands (such as an output optical signal 68).

[0143] According to the wavelength conversion device with the configuration described in [3] above, a WDM optical signal within an arbitrary wavelength band range can be input, and a WDM optical signal of any wavelength different from the input wavelength can be output over a wide bandwidth of wavelengths. Moreover, since an optical device with high wavelength resolution can be used as the wavelength selection switch, the input optical signal can be separated for each wavelength channel and output in the desired direction. Furthermore, when extending the range of the corresponding wavelength conversion to a wider bandwidth, there is no need to replace the existing optical device with another device with different wavelength characteristics.

[0144] [4] The wavelength conversion device described in [1] above, which allows input of an optical signal that has been wavelength-division multiplexed over a wavelength range spanning multiple wavelength bands (such as a WDM optical signal 87 spanning multiple bands), and has the function of allowing selective output of optical signals of multiple wavelengths having wavelength bands different from each other (such as an output optical signal 88).

[0145] According to the wavelength conversion device with the configuration described in [4] above, it is possible to input any WDM optical signal within a wavelength range spanning multiple wavelength bands and output a WDM optical signal of any wavelength different from the input wavelength over a wide bandwidth of wavelengths. Moreover, since an optical device with high wavelength resolution can be used as the wavelength selection switch, the input optical signal can be separated for each wavelength channel and output in the desired direction. Furthermore, when extending the range of the corresponding wavelength conversion to a wider bandwidth, there is no need to replace the existing optical device with another device with different wavelength characteristics.

[0146] [5] The wavelength conversion device according to [1] above, further comprising a control mechanism (120) that controls one or more of the wavelength selection switch (100a, etc.), the wavelength band converter (22, etc.), and the wavelength converter (100b, etc.) depending on the situation.

[0147] According to the wavelength conversion device with the configuration of [5] described above, the wavelength selection switch, the wavelength band converter, and the wavelength converter can be dynamically controlled according to the situation by using the control mechanism. This makes it possible to respond to, for example, changes in the wavelength of the input optical signal or switching of the transmission path through which the optical signal passes.

[0148] [6] The wavelength conversion device according to [5] above, wherein the control mechanism instructs the wavelength converter to adjust control parameters according to the wavelengths of the optical signal before and after wavelength conversion (step S14).

[0149] According to the wavelength conversion device with the configuration of [6] above, it becomes possible to provide appropriate control parameters to the wavelength converter depending on the situation, making it easy to control the wavelength of the optical signal after wavelength conversion with high precision.

[0150] [7] The wavelength conversion device according to [5] above, wherein the control mechanism instructs the wavelength selection switch to select an output port corresponding to the wavelength of the input optical signal (step S14).

[0151] According to the wavelength conversion device with the configuration described in [7] above, even when the input optical signal contains various wavelengths, the path of the optical signal passing through the device can be divided and appropriately controlled for each wavelength, and the output wavelength can be easily controlled for each wavelength of the input light.

[0152] [8] The wavelength conversion apparatus according to [5] above, wherein the control mechanism selects a device to be used from among the wavelength selection switch, the wavelength band converter, and a plurality of devices that can be used as the wavelength converter, depending on the situation (step S13).

[0153] According to the wavelength conversion device with the configuration of [8] described above, the control mechanism can appropriately select the device to be used depending on the situation, making it easy to handle various wavelength bands for the input and output wavelengths to be converted.

[0154] 11-WB, 13-WB Wavelength selection switch 12-WB Wavelength conversion unit 14-1 to 14-M Wavelength converter 15 Input optical signal 16, 17 Optical signal 18 Output optical signal 21-C, 45-C Wavelength selection switch 22, 42, 46, 62 Wavelength band converter 23-C, 44-C Wavelength converter 24, 47, 66, 76 Multiplexer 25 Input optical signal 26, 31, 32 Optical signal 27-C C-band optical signal 27-L, 33-L L-band optical signal 28 Output optical signal 41, 81, 91 Demultiplexer 43 Optical coupler 48 Input optical signal 48-C, 51-C, 52-C, 53-C, 54-C C-band optical signal 48-L, 55-L L-band optical signal 49 Output optical signal 61-C, 63-C, 63-L, 71-C, 74-C Wavelength selection switch 64-C, 64-L, 72-C Wavelength conversion unit 65-C, 65-L, 73-C Wavelength converter 67 WDM optical signal 68 Output optical signal 69 WDM optical signal 75 Wavelength band converter 77-C WDM optical signal 78 Output optical signal 79-C, 87-C C-band optical signal 79-L, 87-L L-band optical signal 82-C, 82-L, 84-C, 84-L Wavelength selection switch 83-1, 83-2, 92, 96 Wavelength band converter 85-C, 85-L Wavelength conversion unit 86, 97 Multiplexer 87 WDM optical signal 88 Output optical signal 93-1, 93-2, 95 Wavelength selection switch 94, 94-1, 94-2 Wavelength conversion unit 98 WDM optical signal 98-C, 99-C C-band optical signal 98-L, 99-L L-band optical signal 99 Output optical signal after wavelength conversion 100, 101, 102, 103, 104, 105, 106 Wavelength conversion device 107, 108, 109 Wavelength conversion device 100a Wavelength selection switch 100b Wavelength converter 111-1 to 111-M Optical coupler 120 Control mechanism B1, B2, B3, B4, B5, B6 Wavelength band BW1, BW2 Wavelength bandwidth F1, F2 Wavelength resolution λ1, λ2, λ3, λ4, λ5, λ6, λ7 Wavelength

Claims

1. A wavelength conversion device comprising: one or more wavelength selection switches having the function of outputting an input optical signal in any direction for each wavelength; one or more wavelength band converters having the function of collectively converting the wavelength of the input optical signal to a wavelength in a different wavelength band determined for each wavelength; one or more wavelength converters having the function of converting the wavelength of the input optical signal to a different wavelength within the same wavelength band; and one or more multiplexers having the function of combining multiple optical signals with different wavelength bands from each other, wherein the wavelength bandwidth of the wavelengths of the input light and / or output light encompasses multiple wavelength bands, and the device has the function of outputting an optical signal of a desired wavelength converted for each wavelength of the input optical signal.

2. The wavelength conversion device according to claim 1, which has the function of allowing input of a single-wavelength optical signal whose wavelength lies within a specific wavelength band or an arbitrary wavelength band as the input optical signal, and allowing selective output of multiple wavelength optical signals whose wavelength bands are different from each other.

3. The wavelength conversion device according to claim 1, which has the function of allowing input of an optical signal that is wavelength-division multiplexed within a specific wavelength band or any wavelength band, and allowing selective output of optical signals of multiple wavelengths whose wavelength bands are different from each other.

4. The wavelength conversion device according to claim 1, which has the function of allowing the input of an optical signal that is wavelength-division multiplexed across a wavelength range spanning multiple wavelength bands, and allowing the selective output of optical signals of multiple wavelengths having wavelength bands that are different from each other.

5. The wavelength conversion device according to claim 1, further comprising a control mechanism that controls one or more of the wavelength selection switch, the wavelength band converter, and the wavelength converter depending on the situation.

6. The wavelength conversion device according to claim 5, wherein the control mechanism instructs the wavelength converter to adjust control parameters according to the wavelengths of the optical signal before and after wavelength conversion.

7. The wavelength conversion device according to claim 5, wherein the control mechanism instructs the wavelength selection switch to select an output port corresponding to the wavelength of the input optical signal.

8. The wavelength conversion apparatus according to claim 5, wherein the control mechanism selects a device to be used from among the wavelength selection switch, the wavelength band converter, and a plurality of devices that can be used as the wavelength converter, depending on the situation.

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