Variable slope equalization device and variable slope equalization method

Abstract

To flatten the slope of an optical intensity profile in a multi-core optical transmission system to increase system cost.SOLUTION: A variable slope equalization device includes first variable slope equalization means including a plurality of pieces of first slope equalization means, second variable slope equalization means including a plurality of pieces of second slope equalization means, multi-input multi-output first matrix switch means connected to the input side of the first variable slope equalization means, multi-input multi-output second matrix switch means that connects the output side of the first variable slope equalization means and the input side of the second variable slope equalization means through a plurality of optical paths, and multi-input multi-output third matrix switch means connected to the output side of the second variable slope equalization means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a variable slope equalizer and a variable slope equalization method, and more particularly to a variable slope equalizer and a variable slope equalization method used in an optical transmission system that uses a multicore fiber. [Background technology]

[0002] In long-distance optical transmission systems such as optical submarine cable systems, it is desirable to keep the slope of the optical intensity profile flat from the beginning of operation (BOL: beginning of life) to the end of life (EOL: end of life) to ensure transmission quality. However, the slope of the optical intensity profile changes due to increased loss caused by repairs and aging of the submarine cable.

[0003] Therefore, in order to keep the slope of the optical intensity profile flat during operation of the optical transmission system, a variable slope equalizer device that can arbitrarily adjust the slope of the optical intensity profile is required. An example of such a variable slope equalizer device is described in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 176894 Summary of the Invention [Problem to be solved by the invention]

[0005] Currently, optical submarine cable systems transmit optical signals in the C-band (Conventional-band) signal band using single-core fibers. In this case, to increase the communication capacity of the optical transmission system, it is necessary to increase the number of optical fibers. However, since there is a limit to the number of optical fibers that can be installed in a submarine cable, it is difficult to increase the number of optical fibers in an optical submarine cable system. For this reason, attempts have been made to use multi-core fibers, in which multiple cores are installed in a single optical fiber, for optical communications, and their practical use in optical submarine cable systems is also being considered.

[0006] In an optical transmission system (multi-core optical transmission system) using such a multi-core fiber, a related variable slope equalizer device 500 as shown in FIG. 7 can be used to keep the slope of the optical intensity profile flat. The related variable slope equalizer device 500 includes fan-in / fan-out devices 511 and 512, multiple slope equalizer devices 521 and 522, and optical switches 531, 532, 533, and 534. The fan-in / fan-out devices 511 and 512 connect each core of the multi-core fiber to a single-core fiber. The slope equalizer devices 521 and 522 adjust the slope of the optical intensity profile of the signal light propagated through the single-core fiber. The optical switches 531, 532, 533, and 534 switch the connection of the slope equalizer devices 521 and 522.

[0007] 7, the related variable slope equalizer apparatus 500 includes nine slope equalizer devices 521, 522. The slope amount of each of the slope equalizer devices 521, 522 is one of −4 dB (decibels), −3 dB, −2 dB, −1 dB, 0 dB, +1 dB, +2 dB, +3 dB, and +4 dB. Therefore, the slope amount adjustment range is from −4 dB to +4 dB.

[0008] In the related variable tilt equalizer apparatus 500, in order to expand the tilt adjustment range, it is necessary to increase the number of tilt equalizer devices 521, 522. Meanwhile, submarine apparatus used in optical submarine cable systems has a limit to the number of optical devices that can be installed in one apparatus. Therefore, if the number of optical devices used for one signal line (core) increases, the number of signal lines (cores) for which the tilt can be adjusted by one related variable tilt equalizer apparatus 500 decreases. As a result, in a multi-core system using a large number of signal lines (cores), the number of related variable tilt equalizer apparatuses 500 increases, and the system price increases.

[0009] As described above, flattening the slope of the optical intensity profile in a multi-core optical transmission system increases the system cost.

[0010] An object of the present invention is to provide a variable slope equalization device and a variable slope equalization method that solve the above-mentioned problem that flattening the slope of the optical intensity profile in a multi-core optical transmission system increases the system cost. [Means for solving the problem]

[0011] The variable slope equalization device of the present invention comprises a first variable slope equalization means having a plurality of first slope equalization means, a second variable slope equalization means having a plurality of second slope equalization means, a first matrix switch means with multiple inputs and multiple outputs connected to the input side of the first variable slope equalization means, a second matrix switch means with multiple inputs and multiple outputs connecting the output side of the first variable slope equalization means and the input side of the second variable slope equalization means via a plurality of optical paths, and a third matrix switch means with multiple inputs and multiple outputs connected to the output side of the second variable slope equalization means.

[0012] The variable tilt equalization method of the present invention accepts first input signal light and second input signal light, selects a first gain tilt amount, a second gain tilt amount, a third gain tilt amount, and a fourth gain tilt amount from a plurality of gain tilt amounts, adjusts the slope of the optical intensity profile of the first input signal light by the first gain tilt amount to output a first signal light, adjusts the slope of the optical intensity profile of the second input signal light by the second gain tilt amount to output a second signal light, adjusts the slope of the optical intensity profile of the first signal light by the third gain tilt amount to output a first output signal light, and adjusts the slope of the optical intensity profile of the second signal light by the fourth gain tilt amount to output a second output signal light. [Effects of the Invention]

[0013] According to the variable slope equalization device and variable slope equalization method of the present invention, it is possible to flatten the slope of the optical intensity profile in a multi-core optical transmission system without increasing the system cost. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a configuration of a variable slope equalizer according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram illustrating the configuration of a variable slope equalizer according to a first embodiment of the present invention. [Figure 3] 3 is a flowchart illustrating a variable slope equalization method according to the first embodiment of the present invention. [Figure 4] FIG. 10 is a block diagram showing the configuration of a variable slope equalizer according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a diagram for explaining the operation of the variable slope equalizer according to the second embodiment of the present invention. [Figure 6A] FIG. 10 is a diagram showing combinations of gain tilt amounts of a first slope equalizer and a second slope equalizer included in a variable slope equalizer according to a second embodiment of the present invention. [Figure 6B]FIG. 10 is a diagram showing combinations of gain tilt amounts of a first slope equalizer and a second slope equalizer included in a variable slope equalizer according to a second embodiment of the present invention. [Figure 6C] FIG. 10 is a diagram showing combinations of gain tilt amounts of a first slope equalizer and a second slope equalizer included in a variable slope equalizer according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a block diagram showing the configuration of a related variable slope equalizer device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] [First embodiment] 1 is a block diagram showing the configuration of a variable slope equalizer 1000 according to a first embodiment of the present invention. The variable slope equalizer 1000 includes a first variable slope equalizer unit (first variable slope equalizer means) 1100, a second variable slope equalizer unit (second variable slope equalizer means) 1200, a first matrix switch unit (first matrix switch means) 1310, a second matrix switch unit (second matrix switch means) 1320, and a third matrix switch unit (third matrix switch means) 1330. The variable slope equalizer 1000 is preferably used in an optical submarine cable system that uses a multicore fiber.

[0017] The first variable slope equalizer section 1100 includes a plurality of first slope equalizers (first slope equalization means) 1110. The second variable slope equalizer section 1200 includes a plurality of second slope equalizers (second slope equalization means) 1210.

[0018] The first matrix switch section 1310 is a multi-input, multi-output matrix switch connected to the input side of the first variable slope equalizer section 1100. The second matrix switch section 1320 is a multi-input, multi-output matrix switch that connects the output side of the first variable slope equalizer section 1100 and the input side of the second variable slope equalizer section 1200 via multiple optical paths. The third matrix switch section 1330 is a multi-input, multi-output matrix switch connected to the output side of the second variable slope equalizer section 1200.

[0019] As described above, the variable slope equalizer 1000 according to this embodiment includes a first matrix switch unit 1310 in the upstream stage and a third matrix switch unit 1330 in the downstream stage. The variable slope equalizer 1000 is configured such that the first variable slope equalizer unit 1100 and the second variable slope equalizer unit 1200 are connected in series via multiple optical paths via the second matrix switch unit 1320. Therefore, by arbitrarily combining multiple first slope equalizers 1110 and multiple second slope equalizers 1210 for each of multiple input signal beams, it is possible to compensate for the slopes of the optical intensity profiles of the input signal beams. As a result, the number of first slope equalizers 1110 and second slope equalizers 1210 can be reduced compared to when optical switches are used (see FIG. 7 ). Therefore, even if there is a limit to the number of optical devices that can be installed in one apparatus, it is possible to flatten the slopes of the optical intensity profiles of multiple input signal beams using a single variable slope equalizer 1000. That is, according to the variable slope equalizer 1000 of this embodiment, it is possible to flatten the slope of the optical intensity profile in a multi-core optical transmission system without increasing the system cost.

[0020] The configuration of the variable slope equalizer 1000 will be described in more detail with reference to FIG.

[0021] The first matrix switch unit 1310 accepts the first input signal light 11 and the second input signal light 21, and connects the first input signal light 11 and the second input signal light 21 to the input side of the first variable slope equalization unit 1100 via different optical paths.

[0022] One first slope equalizer 1111 of the multiple first slope equalizers 1110 adjusts the slope of the optical intensity profile of the first input signal light 11 by a first gain slope amount T1 and outputs the first signal light 12. Another first slope equalizer 1112 of the multiple first slope equalizers 1110 adjusts the slope of the optical intensity profile of the second input signal light 21 by a second gain slope amount T2 and outputs the second signal light 22.

[0023] Furthermore, one second tilt equalizer 1211 of the multiple second tilt equalizers 1210 adjusts the slope of the optical intensity profile of the first signal light 12 by a third gain tilt amount T3 and outputs a first output signal light 13. Another second tilt equalizer 1212 of the multiple second tilt equalizers 1210 adjusts the slope of the optical intensity profile of the second signal light 22 by a fourth gain tilt amount T4 and outputs a second output signal light 23.

[0024] Here, the second matrix switch section 1320 connects the first slope equalizer 1111, which compensates for the slope of the optical intensity profile of the first input signal light 11 by the sum of the first gain slope T1 and the third gain slope T3, to the second slope equalizer 1211. The second matrix switch section 1320 also connects the first slope equalizer 1112, which compensates for the slope of the optical intensity profile of the second input signal light 21 by the sum of the second gain slope T2 and the fourth gain slope T4, to the second slope equalizer 1212.

[0025] The first variable slope equalizer section 1100 may include a plurality of first slope equalizers 1110 having different first and second gain slope amounts T1 and T2, and the second variable slope equalizer section 1200 may include a plurality of second slope equalizers 1210 having different third and fourth gain slope amounts T3 and T4.

[0026] The third matrix switch section 1330 receives the first output signal light 13 and the second output signal light 23, and sends out the first output signal light 13 and the second output signal light 23 from different connection terminals (connection means).

[0027] The first matrix switch unit 1310 can be configured to receive the first input signal light 11 and the second input signal light 21 that have propagated through different cores of the input-side multicore fiber, and the third matrix switch unit 1330 can be configured to send the first output signal light 13 and the second output signal light 23 to different cores of the output-side multicore fiber.

[0028] Next, the variable slope equalization method according to this embodiment will be described with reference to the flowchart shown in FIG.

[0029] In the variable tilt equalization method according to this embodiment, first, a first input signal light and a second input signal light are received (step S110). Then, a first gain tilt amount, a second gain tilt amount, a third gain tilt amount, and a fourth gain tilt amount are selected from a plurality of gain tilt amounts (step S120). Next, the slope of the optical intensity profile of the first input signal light is adjusted by the first gain tilt amount to output the first signal light, and the slope of the optical intensity profile of the second input signal light is adjusted by the second gain tilt amount to output the second signal light (step S130). Then, the slope of the optical intensity profile of the first signal light is adjusted by the third gain tilt amount to output the first output signal light, and the slope of the optical intensity profile of the second signal light is adjusted by the fourth gain tilt amount to output the second output signal light (step S140).

[0030] With this configuration, the variable slope equalization method of this embodiment can compensate for the slope of the optical intensity profile of each of the multiple input signal lights by arbitrarily combining multiple gain tilt amounts for each of the multiple input signal lights. As a result, the number of types of gain tilt amounts that need to be prepared in advance can be reduced. Therefore, it is possible to flatten the slope of the optical intensity profile of multiple input signal lights without increasing the scale of the system that implements the variable slope equalization method.

[0031] Here, selecting the first, second, third, and fourth gain tilt amounts may include the following selection methods: The first and third gain tilt amounts may be selected so that the sum of the first and third gain tilt amounts compensates for the slope of the optical intensity profile of the first input signal light; and The second and fourth gain tilt amounts may be selected so that the sum of the second and fourth gain tilt amounts compensates for the slope of the optical intensity profile of the second input signal light.

[0032] The first gain tilt amount can be different from the second gain tilt amount, and the third gain tilt amount can be different from the fourth gain tilt amount.

[0033] Receiving the above-mentioned first input signal light and second input signal light can include receiving the first input signal light and the second input signal light that have propagated through different cores of the input-side multicore fiber, respectively.

[0034] As described above, the variable slope equalization device 1000 and variable slope equalization method according to this embodiment can flatten the slope of the optical intensity profile in a multi-core optical transmission system without increasing the system cost.

[0035] Second Embodiment Next, a second embodiment of the present invention will be described. Fig. 4 shows the configuration of a variable slope equalizer 2000 according to this embodiment. The variable slope equalizer 2000 has a first variable slope equalizer section (first variable slope equalizer means) 1100, a second variable slope equalizer section (second variable slope equalizer means) 1200, a first matrix switch section (first matrix switch means) 1310, a second matrix switch section (second matrix switch means) 1320, and a third matrix switch section (third matrix switch means) 1330. The variable slope equalizer 2000 is preferably used in an optical submarine cable system that uses a multicore fiber.

[0036] The first variable slope equalizer section 1100 includes a plurality of first slope equalizers (first slope equalization means) 1110. The second variable slope equalizer section 1200 includes a plurality of second slope equalizers (second slope equalization means) 1210. FIG. 4 shows an example in which the first variable slope equalizer section 1100 and the second variable slope equalizer section 1200 each include five first slope equalizers 1110 and five second slope equalizers 1210, with gain slope amounts of −3 dB (decibels), −1 dB, 0 dB, +1 dB, and +3 dB. In this case, by selecting and connecting one of the first slope equalizers 1110 and one of the second slope equalizers 1210, the gain slope amount can be changed in the range from −4 dB to +4 dB.

[0037] The first matrix switch section 1310 is a multi-input, multi-output matrix switch connected to the input side of the first variable slope equalizer section 1100. The second matrix switch section 1320 is a multi-input, multi-output matrix switch that connects the output side of the first variable slope equalizer section 1100 and the input side of the second variable slope equalizer section 1200 via multiple optical paths. The third matrix switch section 1330 is a multi-input, multi-output matrix switch connected to the output side of the second variable slope equalizer section 1200.

[0038] The configuration and operation of each unit up to this point are similar to those of the variable slope equalizer 1000 according to the first embodiment. The variable slope equalizer 2000 according to this embodiment further includes a first fan-in fan-out connection unit (first fan-in fan-out connection means) 2100 and a second fan-in fan-out connection unit (second fan-in fan-out connection means) 2200.

[0039] The first fan-in / fan-out connection unit 2100 connects different cores of the input-side multicore fiber 2110 to the first single-core fiber 2121 and the second single-core fiber 2122. The second fan-in / fan-out connection unit 2200 connects different cores of the output-side multicore fiber 2210 to the third single-core fiber 2221 and the fourth single-core fiber 2222.

[0040] In this case, the first matrix switch unit 1310 connects the first input signal light propagating through the first single-core fiber 2121 to one first slope equalizer 1111 of the multiple first slope equalizers 1110. Then, the first matrix switch unit 1310 connects the second input signal light propagating through the second single-core fiber 2122 to another first slope equalizer 1112 of the multiple first slope equalizers 1110.

[0041] Moreover, the third matrix switch unit 1330 connects the first output signal light to the third single-core fiber 2221 and the second output signal light to the fourth single-core fiber 2222.

[0042] As described above, the variable slope equalizer 2000 according to this embodiment includes a first matrix switch unit 1310 in the front stage and a third matrix switch unit 1330 in the rear stage. The variable slope equalizer 2000 is configured such that the first variable slope equalizer unit 1100 and the second variable slope equalizer unit 1200 are connected in series via multiple optical paths by the second matrix switch unit 1320. This allows the number of first slope equalizers 1110 and second slope equalizers 1210 to be reduced compared to when optical switches are used (see FIG. 7 ). As a result, the variable slope equalizer 2000 according to this embodiment can flatten the slope of the optical intensity profile in a multi-core optical transmission system without increasing the system cost.

[0043] Next, gain equalization in a multi-core optical transmission system using the variable slope equalizer 2000 of this embodiment will be described with reference to FIG.

[0044] The first input signal light 11 and the second input signal light 21 that have propagated through different cores of the input side multi-core fiber 2110 are introduced into the first single-core fiber 2121 and the second single-core fiber 2122, respectively, by the first fan-in fan-out connection section 2100.

[0045] The first input signal light 11 has its gain tilt equalized by a total of "-4 dB" by the first tilt equalizer 1111 having a gain tilt amount of "-1 dB" and the second tilt equalizer 1211 having a gain tilt amount of "-3 dB" (see FIG. 4). Similarly, the second input signal light 21 has its gain tilt equalized by a total of "+2 dB" by the first tilt equalizer 1112 having a gain tilt amount of "+3 dB" and the second tilt equalizer 1212 having a gain tilt amount of "-1 dB" (see FIG. 4).

[0046] The first output signal light 13 and the second output signal light 23, whose gain tilts have been equalized, are guided through the third single-core fiber 2221 and the fourth single-core fiber 2222, and are connected to different cores of the output multi-core fiber 2210 by the second fan-in fan-out connection unit 2200.

[0047] 4, the first input signal light and the second input signal light propagating through the first single-core fiber 2121 and the second single-core fiber 2122, respectively, are introduced into the first variable slope equalizer 1100 via the first matrix switch unit 1310. In the first variable slope equalizer 1100, the slope of the optical intensity profile of each of the first input signal light and the second input signal light is adjusted by the first slope equalizer 1110 with one of the gain tilt amounts of −3 dB, −1 dB, 0 dB, +1 dB, and +3 dB. Subsequently, in the second variable slope equalizer 1200, the slope of the optical intensity profile is adjusted by the second slope equalizer 1210 with one of the gain tilt amounts of −3 dB, −1 dB, 0 dB, +1 dB, and +3 dB. As a result, the first input signal light and the second input signal light are gain equalized so that the slope of the optical intensity profile becomes flat.

[0048] The gain-equalized first output signal light and second output signal light are output to the third single-core fiber 2221 and the fourth single-core fiber 2222, respectively, via the third matrix switch unit 1330. The first output signal light and the second output signal light are introduced into different cores of the output-side multi-core fiber 2210 by the second fan-in / fan-out connection unit 2200, respectively.

[0049] 6A, 6B, and 6C show combinations of the gain tilt amounts of the first and second slope equalizers. By combining the gain tilt amounts of the first and second slope equalizers, the slope of the optical intensity profile can be adjusted to any gain tilt amount in the range of −4 dB to +4 dB for the first and second input signal lights. The gain tilt adjustment range here is the same as the adjustment range of the related variable slope equalizer device shown in FIG. 7.

[0050] The variable slope equalizer 2000 according to this embodiment includes 15 optical devices in total, including 10 slope equalizers, three matrix switch units, and two fan-in / fan-out connection units. In contrast, the related variable slope equalizer device shown in Fig. 7 includes 24 optical devices in total, including 18 slope equalizer devices, four optical switches, and two fan-in / fan-out devices. Therefore, the variable slope equalizer 2000 according to this embodiment can reduce the number of optical devices used by nine.

[0051] Next, the variable slope equalization method according to this embodiment will be described.

[0052] In the variable tilt equalization method according to this embodiment, first, a first input signal light and a second input signal light are received (step S110 in FIG. 3). Then, a first gain tilt amount, a second gain tilt amount, a third gain tilt amount, and a fourth gain tilt amount are selected from a plurality of gain tilt amounts (step S120 in FIG. 3). Next, the slope of the optical intensity profile of the first input signal light is adjusted by the first gain tilt amount to output the first signal light, and the slope of the optical intensity profile of the second input signal light is adjusted by the second gain tilt amount to output the second signal light (step S130 in FIG. 3). Then, the slope of the optical intensity profile of the first signal light is adjusted by the third gain tilt amount to output the first output signal light, and the slope of the optical intensity profile of the second signal light is adjusted by the fourth gain tilt amount to output the second output signal light (step S140 in FIG. 3).

[0053] The steps up to this point are the same as those in the variable tilt equalization method according to Embodiment 1. In the variable tilt equalization method of this embodiment, a first input signal light and a second input signal light that have propagated through a first single-core fiber and a second single-core fiber, respectively, connected to different cores of an input-side multi-core fiber are accepted.

[0054] Furthermore, the first output signal light and the second output signal light may be respectively output to different cores of an output-side multicore fiber. In this case, the first output signal light and the second output signal light may be respectively output to a third single-core fiber and a fourth single-core fiber connected to different cores of the output-side multicore fiber.

[0055] As described above, the variable slope equalization device 2000 and variable slope equalization method according to this embodiment can flatten the slope of the optical intensity profile in a multi-core optical transmission system without increasing the system cost.

[0056] Some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0057] (Supplementary Note 1) A variable slope equalization device comprising: a first variable slope equalization means having a plurality of first slope equalization means; a second variable slope equalization means having a plurality of second slope equalization means; a first matrix switch means with multiple inputs and multiple outputs connected to the input side of the first variable slope equalization means; a second matrix switch means with multiple inputs and multiple outputs connecting the output side of the first variable slope equalization means and the input side of the second variable slope equalization means via a plurality of optical paths; and a third matrix switch means with multiple inputs and multiple outputs connected to the output side of the second variable slope equalization means.

[0058] (Appendix 2) A variable slope equalization device as described in Appendix 1, wherein the first matrix switch means receives a first input signal light and a second input signal light, and connects the first input signal light and the second input signal light to the input side of the first variable slope equalization means via different optical paths.

[0059] (Supplementary Note 3) A variable slope equalization device as described in Supplementary Note 2, wherein one first slope equalization means among the plurality of first slope equalization means adjusts the slope of the optical intensity profile of the first input signal light by a first gain tilt amount and outputs a first signal light, another first slope equalization means among the plurality of first slope equalization means adjusts the slope of the optical intensity profile of the second input signal light by a second gain tilt amount and outputs a second signal light, one second slope equalization means among the plurality of second slope equalization means adjusts the slope of the optical intensity profile of the first signal light by a third gain tilt amount and outputs a first output signal light, and another second slope equalization means among the plurality of second slope equalization means adjusts the slope of the optical intensity profile of the second signal light by a fourth gain tilt amount and outputs a second output signal light.

[0060] (Appendix 4) A variable slope equalization device as described in Appendix 3, wherein the second matrix switch means connects the one first slope equalization means and the one second slope equalization means, which compensate for the slope of the optical intensity profile of the first input signal light by the sum of the first gain slope amount and the third gain slope amount, and connects the other first slope equalization means and the other second slope equalization means, which compensate for the slope of the optical intensity profile of the second input signal light by the sum of the second gain slope amount and the fourth gain slope amount.

[0061] (Appendix 5) A variable slope equalization device as described in Appendix 3 or 4, wherein the first variable slope equalization means includes the plurality of first slope equalization means whose first gain slope amount and second gain slope amount are different, and the second variable slope equalization means includes the plurality of second slope equalization means whose third gain slope amount and fourth gain slope amount are different.

[0062] (Appendix 6) A variable slope equalization device according to appendix 3 or 4, wherein the third matrix switch means receives the first output signal light and the second output signal light, and outputs the first output signal light and the second output signal light from different connection means.

[0063] (Supplementary Note 7) The first matrix switch means receives the first input signal light and the second input signal light which have propagated through different cores of an input-side multi-core fiber, respectively; 5. The variable slope equalizer according to claim 3, wherein the third matrix switch means outputs the first output signal light and the second output signal light to different cores of an output-side multicore fiber.

[0064] (Supplementary Note 8) A variable slope equalizer according to Supplementary Note 7, further comprising: first fan-in fan-out connection means for connecting different cores of the input-side multicore fiber to a first single-core fiber and a second single-core fiber, respectively; and second fan-in fan-out connection means for connecting different cores of the output-side multicore fiber to a third single-core fiber and a fourth single-core fiber, respectively.

[0065] (Supplementary Note 9) A variable slope equalization device according to Supplementary Note 8, wherein the first matrix switch means connects the first input signal light propagated through the first single-core fiber to one of the first slope equalization means and connects the second input signal light propagated through the second single-core fiber to the other first slope equalization means, and the third matrix switch means connects the first output signal light to the third single-core fiber and connects the second output signal light to the fourth single-core fiber.

[0066] (Supplementary Note 10) A variable tilt equalization method that receives first input signal light and second input signal light, selects a first gain tilt amount, a second gain tilt amount, a third gain tilt amount, and a fourth gain tilt amount from a plurality of gain tilt amounts, adjusts the slope of an optical intensity profile of the first input signal light by the first gain tilt amount, and outputs a first signal light, adjusts the slope of an optical intensity profile of the second input signal light by the second gain tilt amount, and outputs a second signal light, adjusts the slope of an optical intensity profile of the first signal light by the third gain tilt amount, and outputs a first output signal light, and adjusts the slope of an optical intensity profile of the second signal light by the fourth gain tilt amount,

[0067] (Supplementary Note 11) The variable slope equalization method according to Supplementary Note 10, wherein selecting the first, second, third, and fourth gain tilt amounts includes selecting the first and third gain tilt amounts so that a sum of the first and third gain tilt amounts compensates for the slope of the optical intensity profile of the first input signal light, and selecting the second and fourth gain tilt amounts so that a sum of the second and fourth gain tilt amounts compensates for the slope of the optical intensity profile of the second input signal light.

[0068] (Appendix 12) The variable slope equalization method according to appendix 10 or 11, wherein the first gain tilt amount is different from the second gain tilt amount, and the third gain tilt amount is different from the fourth gain tilt amount.

[0069] (Appendix 13) The variable slope equalization method according to appendix 10 or 11, wherein accepting the first input signal light and the second input signal light includes accepting the first input signal light and the second input signal light that have propagated through different cores of an input-side multicore fiber, respectively.

[0070] (Appendix 14) A variable tilt equalization method according to appendix 13, wherein receiving the first input signal light and the second input signal light includes receiving the first input signal light and the second input signal light that have propagated through a first single-core fiber and a second single-core fiber, respectively, connected to different cores of the input-side multi-core fiber.

[0071] (Appendix 15) The variable tilt equalization method according to appendix 10 or 11, further comprising sending the first output signal light and the second output signal light to different cores of an output-side multicore fiber, respectively.

[0072] (Supplementary Note 16) The variable tilt equalization method according to Supplementary Note 15, wherein sending out the first output signal light and the second output signal light includes sending out the first output signal light and the second output signal light to a third single-core fiber and a fourth single-core fiber, respectively, which are connected to different cores of the output-side multi-core fiber.

[0073] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. [Explanation of symbols]

[0074] 1000, 2000 variable slope equalizer 1100 First variable slope equalizer 1110, 1111, 1112 First slope equalizer 1200 Second variable slope equalizer 1210, 1211, 1212 Second slope equalizer 1310 First matrix switch section 1320 Second matrix switch section 1330 Third Matrix Switch Section 2100 First Fan-in / Fan-out Connection 2110 Input multi-core fiber 2121 First single-core fiber 2122 Second Single-Core Fiber 2200 Second Fan-in / Fan-out Connection 2210 Output multi-core fiber 2221 The third single-core fiber 2222 The fourth single-core fiber 500 Associated variable slope equalizer device 511, 512 Fan-in Fan-out Devices 521, 522 Gradient equalizer device 531, 532, 533, 534 Optical switches

Claims

1. a first variable slope equalization means comprising a plurality of first slope equalization means; a second variable slope equalization means comprising a plurality of second slope equalization means; a first matrix switch means having multiple inputs and multiple outputs connected to the input side of the first variable slope equalization means; a second matrix switch means with multiple inputs and multiple outputs that connects the output side of the first variable slope equalizer means and the input side of the second variable slope equalizer means via a plurality of optical paths; a third matrix switch means having multiple inputs and multiple outputs connected to the output side of the second variable slope equalization means; Variable slope equalizer.

2. The first matrix switch means receives a first input signal light and a second input signal light, and connects the first input signal light and the second input signal light to the input side of the first variable slope equalization means through different optical paths.

2. A variable slope equalizer according to claim 1.

3. one of the plurality of first tilt equalizers adjusts the tilt of the optical intensity profile of the first input signal light by a first gain tilt amount and outputs the first signal light; another first tilt equalization means among the plurality of first tilt equalization means adjusts the tilt of the optical intensity profile of the second input signal light by a second gain tilt amount and outputs the second signal light; one second tilt equalizer of the plurality of second tilt equalizers adjusts the tilt of the optical intensity profile of the first signal light by a third gain tilt amount and outputs a first output signal light; Another second tilt equalizer of the plurality of second tilt equalizers adjusts the tilt of the optical intensity profile of the second signal light by a fourth gain tilt amount and outputs a second output signal light.

3. A variable slope equalizer according to claim 2.

4. The second matrix switch means connecting the one first tilt equalizer and the one second tilt equalizer, which compensate for the tilt of the optical intensity profile of the first input signal light by the sum of the first gain tilt amount and the third gain tilt amount; The other first tilt equalization means and the other second tilt equalization means are connected to compensate for the tilt of the optical intensity profile of the second input signal light by the sum of the second gain tilt amount and the fourth gain tilt amount.

4. A variable slope equalizer according to claim 3.

5. the first variable tilt equalizer includes the plurality of first tilt equalizers, each having a different first gain tilt amount and a different second gain tilt amount; The second variable tilt equalizer includes the plurality of second tilt equalizers having different third and fourth gain tilt amounts.

5. A variable slope equalizer according to claim 3 or 4.

6. The third matrix switch means receives the first output signal light and the second output signal light, and outputs the first output signal light and the second output signal light from different connection means.

5. A variable slope equalizer according to claim 3 or 4.

7. the first matrix switch means receives the first input signal light and the second input signal light which have propagated through different cores of an input-side multi-core fiber, The third matrix switch means transmits the first output signal light and the second output signal light to different cores of an output-side multi-core fiber, respectively.

5. A variable slope equalizer according to claim 3 or 4.

8. a first fan-in / fan-out connection means for connecting different cores of the input-side multicore fiber to a first single-core fiber and a second single-core fiber, respectively; and a second fan-in / fan-out connection means for connecting different cores of the output-side multicore fiber, a third single-core fiber, and a fourth single-core fiber, respectively.

8. A variable slope equalizer according to claim 7.

9. the first matrix switch means connects the first input signal light propagated through the first single-core fiber to one of the first gradient equalization means, and connects the second input signal light propagated through the second single-core fiber to the other first gradient equalization means; The third matrix switch means connects the first output signal light to the third single-core fiber and the second output signal light to the fourth single-core fiber.

9. A variable slope equalizer according to claim 8.

10. receiving a first input signal light and a second input signal light; selecting a first gain tilt amount, a second gain tilt amount, a third gain tilt amount, and a fourth gain tilt amount from the plurality of gain tilt amounts; adjusting a slope of an optical intensity profile of the first input signal light by the first gain tilt amount, and outputting the first signal light; adjusting a slope of an optical intensity profile of the second input signal light by the second gain tilt amount, and outputting the second signal light; adjusting the tilt of the optical intensity profile of the first signal light by the third gain tilt amount, and outputting a first output signal light; The tilt of the optical intensity profile of the second signal light is adjusted by the fourth gain tilt amount, and a second output signal light is output. Variable slope equalization method.

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