JP5659341B2 - Multi-core optical transmission system, optical amplification and optical amplification components - Google Patents

Description

  The present invention relates to an optical fiber amplifier used in multi-core optical transmission.

  In order to drastically increase the transmission capacity of an optical transmission system, development of a multi-core optical transmission system using a multi-core fiber having a plurality of cores in one fiber as a transmission path has been advanced. Compared to the case where a conventional fiber having one core is used as a transmission line by propagating a wavelength division multiplexing (WDM) signal transmitting different information to each core of the multi-core fiber. The transmission capacity can be dramatically increased.

  In a long-distance multi-core optical transmission system, a multi-core fiber amplifier is indispensable in order to amplify signal light whose intensity is reduced during transmission, as in a conventional optical transmission system using a single core fiber as a transmission path.

  A conventional multi-core fiber amplifier uses a fan-in / fan-out for signal light and pump light for each core to an amplification multi-core fiber having each core doped with Er ions which are one of a plurality of rare earth elements. By inputting, the signal lights that are independently input to the seven cores are simultaneously amplified (Non-Patent Document 1).

H. Takahashi et al., “First demonstration of MC-EDFA-repeatered SDM transmission of 40 x 128-Gbit / s PDM-QPSK signals per core over 6,160-km 7-core MCF,” in Proc. ECOC2012, Postdeadline papers, Th.3.C.3, 2012 Masuda, “Examination of Hybrid Wavelength and Spatial Multiplexing System Configuration,” 2012 IEICE General Conference B-10-81

  However, the conventional multi-core optical amplifier has a pumping light source, a multiplexer that combines the pumping light and signal light for each core, and uses an amplification fiber (erbium-doped multi-core fiber) having the same number of cores as the transmission multi-core fiber. There is a problem that the number of components increases.

  Also, in a multi-core optical amplifier, a signal propagating through each core of the amplification multi-core fiber leaks to other cores, thereby causing cross-talk between the cores and deteriorating transmission characteristics. In addition, multicore optical amplifiers that amplify signal light in the L band (1565-1625 nm) require a longer length of multicore fiber for amplification than multicore optical amplifiers that amplify signal light in the C band (1530-1565 nm). Therefore, transmission degradation may occur due to non-linear optical effects, particularly crosstalk due to four-wave mixing (FWM).

  The present invention has been made in view of the above circumstances, an optical amplifier capable of reducing the number of components of an optical amplifier, and suppressing crosstalk due to leakage light between cores and nonlinear optical effects, and a multi-core using the optical amplifier An object of the present invention is to provide an optical transmission system and an optical amplification component that enables the above-described effects.

In order to achieve such an object, the present invention includes an optical amplifier as an optical repeater, and a transmission multi-core fiber having a plurality of cores as a transmission path, A multi-core optical transmission system that transmits a plurality of WDM signals having different wavelength arrangements in either one of a C band and an L band in a plurality of adjacent cores of the transmission multi-core fiber, wherein the optical amplifier includes the transmission At least one set of interleavers including an interleaver that inputs and combines a plurality of WDM signals having different wavelength arrangements that propagate through different cores among adjacent cores of the multicore fiber for use, and from the interleaver And adding at least one set of multiplexer / demultiplexer including a multiplexer / demultiplexer for multiplexing the plurality of multiplexed WDM signals and pumping light, and adding rare earth ions An amplifying fiber having at least one core, each of the at least one set of multiplexers / demultiplexers being connected to one of the at least one core of the amplifying fiber. It is comprised so that it may connect to.

The invention according to claim 2 is the multi-core optical transmission system according to claim 1, wherein the number of sets of the at least one set of interleavers and the at least one set of multiplexers / demultiplexers is two or more, The number of cores of the amplification fiber having the at least one core is plural, and the optical amplifier is configured to connect each of the at least one set of multiplexer / demultiplexers to the amplification fiber. And a set of fan-outs connected to one of the plurality of cores.

The invention according to claim 3 is the multi-core optical transmission system according to claim 2, wherein the number of cores of the amplification fiber is the number of cores of the transmission multi-core fiber connected to the input / output of the optical amplifier. It is smaller than the number of cores.

The invention according to claim 4 is the multi-core optical transmission system according to claim 2 or 3, wherein the propagation directions of the signal light are opposite in adjacent cores among the plurality of cores of the amplification fiber. In addition, each of the at least one set of multiplexers / demultiplexers is connected to the one set of fan-outs.

The invention according to claim 5 is the multi-core optical transmission system according to any one of claims 1 to 3, wherein two WDM signals are propagated and amplified in opposite directions in the same core of the amplification fiber. It is characterized by that.

  As described above, the multi-core optical transmission system using the optical amplifier using the optical amplifying component of the present invention as an optical repeater reduces the number of components and prevents crosstalk due to leakage light between cores and nonlinear optical effects. It has the advantage of enabling suppression.

It is a block diagram explaining the structure of the multi-core optical transmission system and optical amplifier of this invention. It is a figure which shows an example of the cross-sectional structure of the multicore fiber for transmission. The figure which shows an example of the cross-sectional structure of the multi-core fiber for amplification. It is a figure explaining the wavelength arrangement | positioning (frequency arrangement | positioning) of the WDM signal in the multi-core optical transmission system and optical amplifier of this invention, (a) And (b) is wavelength arrangement | positioning of the WDM signal which propagates each core of the multicore fiber for transmission. It is a figure which shows (frequency arrangement | positioning), (c) is a figure which shows wavelength arrangement | positioning (frequency arrangement | positioning) of the WDM signal which propagates the core of the multi-core fiber for amplification. It is a block diagram explaining the structure of the optical amplifier using the multi-core optical transmission system of this invention and the amplification fiber which has one core. In this invention, it is a block diagram explaining the structure of a multi-core optical transmission system and an optical amplifier when signal light propagation is set oppositely between the adjacent cores of the multi-core fiber for amplification. In this invention, it is a block diagram explaining the structure which carries out opposite amplification of the WDM signal to interleave. 1 is a block diagram illustrating the configuration of a multi-core optical transmission system and an optical amplifier according to a first embodiment of the present invention. It is a figure which shows the cross-section of the transmission multi-core fiber in the 1st Embodiment of this invention. It is a figure which shows the cross-section of the multicore fiber for amplification in the 1st Embodiment of this invention. It is a block diagram explaining the structure of the multi-core optical transmission system and optical amplifier of 2nd Embodiment of this invention. It is a block diagram explaining the structure of the multi-core optical transmission system and optical amplifier of the 3rd Embodiment of this invention. It is a block diagram explaining the structure of the multi-core optical transmission system and optical amplifier of 4th Embodiment of this invention.

The multi-core optical transmission system, optical amplifier, and optical amplification component of the present invention have the following characteristics.
・ Multi-core optical transmission system
-A multi-core fiber having a plurality of cores in one fiber is used as a transmission line.
-Wavelength arrangement (frequency arrangement) of WDM signals transmitted in adjacent cores of multi-core fiber is different.
-It is optically relayed by an optical amplifier that amplifies a WDM signal obtained by combining multiple WDM signals with different wavelength arrangements (frequency arrangements).
・ Optical amplifier
-Equipped with an interleaver that multiplexes and demultiplexes multiple WDM signals with different wavelength arrangements (frequency arrangements).
-Optical amplification is performed by propagating signal light in the opposite direction in one core or adjacent core.
・ Optical amplification parts
-An optical amplification component in which an interleaver, an excitation / signal multiplexer / demultiplexer that multiplexes / demultiplexes excitation light and signal light is integrated in a quartz-based planar lightwave circuit or a silicon optical integrated circuit.

(Function)
FIG. 1 shows a block diagram of an optical repeater of the multi-core optical transmission system of the present invention. In FIG. 1, 1 is a transmission multi-core fiber, and 2 is an optical amplifier. The optical amplifier 2 includes an amplification fiber 3, a pumping light source 4, a pumping / signal multiplexer / demultiplexer 5 that combines pumping light and signal light, an optical isolator 6, fanouts 7 and 8, and an interleaver 9. With.

  2 and 3 show cross-sectional structures of an amplifying multi-core fiber that can be used as the transmitting multi-core fiber 1 and the amplifying fiber 3 used in the multi-core fiber transmission line, respectively.

  A transmission multi-core fiber 1 shown in FIG. 2 is a multi-core fiber having four cores in one fiber. Of the four cores, the WDM signal-1 having the wavelength arrangement (frequency arrangement) shown in FIG. 4A is propagated to the core 11, and the wavelength arrangement (frequency) shown in FIG. WDM signal-2 is propagated. The WDM signal-1 and the WDM signal-2 are both WDM signals having a frequency interval S, but the wavelength (frequency) arrangements are shifted from each other by S / 2.

  On the other hand, the multicore fiber for amplification shown in FIG. 3 is a multicore fiber having two cores in one fiber, and the core includes rare earth ions (for example, Er ions) and transition metal ions (for example, Cr ions) for optical amplification. ) Is added.

  The interleaver 9 provided in the optical amplifier 2 connects the input WDM signal-1 and WDM signal-2 to the input of the pump / signal multiplexer / demultiplexer 5. In the configuration shown in FIG. 1, the interleaver 9 combines the input WDM signal-1 and the WDM signal-2, and the WDM signal (WDM signal-1 + WDM signal) having the wavelength arrangement (frequency arrangement) shown in FIG. -2) is output, or conversely, the WDM signal (WDM signal-1 + WDM signal-2) having the wavelength arrangement shown in FIG. 3 is input, and the WDM signal-1 shown in FIG. b) has a function of demultiplexing into the WDM signal-1.

  In the input section of the optical amplifier 2 (for example, on the left side of the drawing), the fanout 7 is configured so that the two cores 11 of the input multi-core fiber 1 are input to different interleavers 9 and the two cores 12 are different. Connect to input of interleaver 9. The interleaver 9 connects each of the combined WDM signals (WDM signal-1 + WDM signal-2) to the input of a separate optical isolator 6.

  The optical isolator 6 connects the WDM signal (WDM signal-1 + WDM signal-2) to the input of the pump / signal multiplexer / demultiplexer 5.

  Each of the pump / signal multiplexer / demultiplexer 5 multiplexes the WDM signal (WDM signal-1 + WDM signal-2) and the pumping light from the pumping light source 4 and one fan connected to both ends of the amplification fiber 3. Connect to the out 8 input.

  The fan-out 8 connects each of the WDM signals (WDM signal-1 + WDM signal-2) combined with the pumping light to one core (core 21 or core 22) of the amplification fiber 3. The amplification fiber 3 connects the WDM signal (WDM signal-1 + WDM signal-2) propagated through the core to the other fan-out 8.

  At the output part of the optical amplifier 2 (for example, on the right side of the drawing), the fanout 8 (other fanouts) separates each of the WDM signals (WDM signal-1 + WDM signal-2) similarly to the input part. / Connect to the input of the signal multiplexer / demultiplexer 5.

  Each of the pump / signal multiplexer / demultiplexer 5 has a function of terminating the residual pump light transmitted without being absorbed, and connects the WDM signal (WDM signal-1 + WDM signal-2) to the input of the optical isolator 6.

  Each of the optical isolators 6 connects the WDM signal (WDM signal-1 + WDM signal-2) combined with the pump light to the input of the interleaver 9.

  Each of the interleavers 9 demultiplexes the WDM signal-1 and the WDM signal-2 and connects them to the input of the fan-out 7.

  At the output section of the optical amplifier 2 (for example, on the right side of the drawing), the fan-out 7 sends the two cores 11 of the transmission-side multi-core fiber 1 to the outputs of the different interleavers 9 in the same manner as the input section. One core 12 is connected to the output of a different interleaver 9.

  As a result, both the core 21 and the core 22 of the amplification fiber 3 can amplify the WDM signal of WDM signal-1 + WDM signal-2. That is, the WDM signal (WDM signal-1 + WDM signal-2) propagating through the two cores of the transmission multicore fiber 1 can be amplified by one core of the amplification fiber 3, and the excitation light source 4 provided for each core, The number of signal multiplexers / demultiplexers 5 and optical isolators 6 can be reduced to ½, and the size of the optical amplifier can be reduced. Further, the amplification fiber 3 has half the number of cores accommodated per fiber as compared with the transmission multi-core fiber 1, so that the diameter of the fiber can be reduced and the volume of the fiber itself can be reduced. As a result, the mechanical strength against bending increases and the diameter of the bobbin around which the amplification fiber 3 is wound can be reduced, which contributes to the reduction of the size of the optical amplifier.

  The number of cores of the amplification fiber 3 is not necessarily ½ of the number of cores of the transmission multi-core fiber 1, and the core number ratio is determined by the number of WDM signals that the interleaver 9 multiplexes / demultiplexes. For example, by using an interleaver that multiplexes and demultiplexes four WDM signals having signal frequencies that are different from each other by S / 4 frequency at frequency interval S, the number of cores of amplification fiber 3 is 1 / number of cores of multicore fibers for transmission. 4

  Furthermore, the present invention can also be applied when the number of cores of the transmission multi-core fiber is two. In this case, the number of amplification fiber cores required for amplifying a WDM signal obtained by combining two WDM signals may be one.

  FIG. 5 shows a configuration of the optical amplifier 20 suitable for the case where the number of cores of the transmission multicore fiber is two. The configuration of the optical amplifier 20 is that a pair of pump / signal multiplexer / demultiplexers 5 that multiplex pump light from the pump light source 4 and signal light are connected to an amplification fiber 30 having one core. This is different from the configuration of the optical amplifier 2 shown in FIG. In the configuration shown in FIG. 5, WDM signal-1 and WDM signal-2 having different wavelength arrangements (frequency arrangements) propagated through the two cores of the transmission multicore fiber are caused by fan-out 7 on the input side of optical amplifier 20. The combined WDM signals (WDM signal-1 and WDM signal-2) combined with the pump / signal multiplexer / demultiplexer 5 and the pump light are combined and input to one core of the amplification fiber 30. . Thereby, a plurality of WDM signals propagating through the respective cores of the multi-core fiber 1 can be amplified by one core of the amplification fiber.

  By the way, in the transmission multi-core fiber 1 as described above, propagation of WDM signals having different wavelength arrangements between adjacent cores has an effect of reducing inter-core crosstalk, as shown in Non-Patent Document 2. is there.

  On the other hand, each core of the amplifying multi-core fiber 3 amplifies a WDM signal having the same wavelength arrangement, but the length of the amplifying fiber 3 is several meters to several hundred meters and is several tens of kilometers. Since the fiber length is significantly shorter than that of the multi-core fiber 1, the crosstalk between the cores is not a problem in most cases even if the WDM signals having the same wavelength arrangement are amplified in the adjacent cores.

  However, when it is necessary to reduce the crosstalk between adjacent cores in the amplification fiber 3, the crosstalk between the cores is reversed by reversing the signal propagation directions between the core 21 and the core 22, as shown in FIG. Can be reduced.

  In the configuration shown in FIG. 6, one of the outputs of the two pump / signal multiplexer / demultiplexers 5 on the input section side of the optical amplifier 2 is connected to one end of the amplifying fiber 3. The other of the outputs of the two pump / signal multiplexer / demultiplexers 5 is connected to the other fan-out 8 of the optical amplifier 2 (the fan on the output side of the optical amplifier 2). Connected to OUT 8).

  Another problem, crosstalk suppression by four-wave mixing (FWM) generated in the amplification fiber 3, is amplified by the same core using the optical amplifier configuration shown in FIG. By setting the propagation directions of WDM signal-1 and WDM signal-2 opposite to each other, the frequency interval of the WDM signal light amplified in each direction becomes S, and the frequency interval S / 2 in the optical amplifier configuration of FIG. Become bigger. Since the generation efficiency of the FWM light that becomes crosstalk becomes smaller as the number of wavelengths of the WDM signal is smaller and the frequency interval of the WDM signal is larger, by using the optical amplifier configuration shown in FIG. 7 for the L-band optical amplifier, An optical amplifier that suppresses crosstalk due to FWM becomes possible.

  In the configuration shown in FIG. 7, four optical isolators 6 are installed between the fan-out 7 and the interleaver 9 at the input section of the optical amplifier 2, and two of the four optical isolators 6 are used for transmission on the input side. The two cores 11 of the multicore fiber 1 are connected to the inputs of different interleavers 9 on the input side, and the remaining two optical isolators 6 are connected to the two cores 12 of the transmission multicore fiber 1 on the output side. Each is connected to the output of a different interleaver 9. Similarly, the output section of the optical amplifier 2 is provided with four optical isolators 6 connected to the fan-out 7 and the interleaver 9. In the configuration of FIG. 7, the interleaver 9 and the excitation / signal multiplexer / demultiplexer 5 can be integrated as a single quartz-based planar lightwave circuit (PLC).

  In the configuration of the optical amplifier 20 shown in FIG. 5, similarly to the configuration of FIG. 7, two optical isolators 6 connected to the fan-out 7 and the interleaver 9 are arranged. One of them connects the core 11 of the input-side transmission multi-core fiber 1 to the input of the input-side interleaver 9, and the other of the optical isolators 6 connects the core 12 of the input-side transmission multi-core fiber 1 to the output-side. A similar effect can be obtained by connecting to the output of the interleaver 9.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 8 shows a first embodiment of the present invention. The transmission multi-core fiber 101 has 12 cores, a core pitch of 40 μm, and a cladding diameter of 215 μm. The refractive index distribution around each core is a trench type, reducing the influence of crosstalk from adjacent cores. Each core is connected by fanout 107 to a single core fiber with one core per fiber.

  FIG. 9 is a diagram showing a cross-sectional structure of the transmission multi-core fiber 101. The twelve cores are a core 111 that propagates 48 WDM signals arranged at intervals of 100 GHz from 1527.22 nm (196.30 THz) to 1556.68 nm (191.60 THz), and 1527.60 nm (196.25 THz) to 1556.09 nm (191.55). The cores 112 that propagate 48-wave WDM signals arranged at intervals of 100 GHz at THz) are arranged in an annular shape in order. The core 111 and the core 112 are designed to have the same fiber parameters such as cutoff wavelength and mode field diameter. Two WDM signals transmitted through the pair of cores 111 and 112 are combined by one interleaver 109. The amplification fiber 103 is a multi-core fiber having six cores arranged in an annular shape as in the cross-sectional structure shown in FIG. 10, and has a core pitch of 50 μm and a cladding diameter of 160 μm. Each core amplifies a WDM signal (wavelength arrangement is 157.29 nm (196.30 THz) to 1565.09 nm (191.55 THz) spaced at 50 GHz intervals) combined by an interleaver. The WDM signals amplified by one core of the amplification fiber 103 connected to the six interleavers 109 by the fan-out 108 are WDM signals having two different wavelength arrangements at intervals of 100 GHz by the interleaver 109 on the output side of the optical amplifier 102. The signal is demultiplexed and input to the pair of cores 111 and 112 of the transmission multi-core fiber 103. Each core of the amplification fiber 103 is multiplexed by the interleaver 109 with the 980 nm band pumping light generated by the 980 nm band semiconductor laser (LD) as the pumping light source 104 by the pump / signal multiplexer / demultiplexer 105 for each core. The WDM signal is input via the fan-out 108. The pump / signal multiplexer / demultiplexer 105 connected to the output side of the amplification fiber 103 via the fan-out 108 is arranged to terminate the residual pump light that has been transmitted without being absorbed by the amplification fiber 103. . Er ions are added to each core of the amplifying fiber, and the Er ions are excited by 980 nm band excitation light, and the wavelength arrangement is from 157.222 nm (196.30 THz) to 1565.09 nm (191.55 THz). Amplified. The additive concentration of Er and the multicore fiber parameters are set so that the absorption loss at 1530 nm is 12 dB / m. The length of the amplification fiber is 7.5 m, and the gain of the optical amplifier is 22 dB or more for each core. As the interleaver 109, an interleaver composed of a lens, a prism, a mirror, and a GT (Gires-Tournois) etalon is used. As the excitation / signal multiplexer / demultiplexer 105, a multiplexer composed of a lens and a dielectric multilayer filter is used. Using. Table 1 shows a comparison of the number of components between the conventional multi-core optical amplifier and the optical amplifier of this embodiment. In this embodiment, the number of components can be reduced to about 2/3 of the conventional one.

(Second Embodiment)
FIG. 11 shows a second embodiment of the present invention. In the optical amplifier 102 in this embodiment, the propagation directions of signal light (WDM signals) in the core 121 and the core 122 of the amplification fiber 103 are reversed. In the configuration shown in FIG. 11, focusing on two of the six excitation / signal multiplexer / demultiplexers 105 on the input side of the optical amplifier 102, one of the outputs of the excitation / signal multiplexer / demultiplexer 105 is amplified. One end of the optical fiber 103 is connected to one fanout 108 (the fanout 108 on the input side of the optical amplifier 102), and the other of the outputs of the two pump / signal multiplexer / demultiplexers 105 is an optical amplifier. 102 is connected to the other fan-out 108 (the fan-out 108 on the output side of the optical amplifier 102).

  By setting the signal light propagation direction in this way, no crosstalk occurs between the adjacent cores (core 121 and core 122) among the six cores of the amplification fiber 103. It is sufficient to consider crosstalk between the cores 122. That is, the core pitch between the nearest cores 121 and between the nearest cores 122 can be set to 50 μm, which is the same as that of the amplification fiber of the first embodiment. At this time, the clad diameter was 118 μm (the clad thickness was substantially equal in the amplification fibers of the first and second embodiments), and the cross-sectional area of the amplification fiber could be reduced by 46%. In addition, the additive concentration of Er and the multi-core fiber parameters are set so that the absorption loss at 1530 nm is 12 dB / m as in the first embodiment, and the required fiber length is equal. The volume of can also be reduced by 46%. Table 2 shows a comparison of the number of components between the conventional multi-core optical amplifier and the optical amplifier of the present embodiment. In this embodiment, the number of components can be reduced to about 2/3 of the conventional one.

(First reference form)
FIG. 12 shows a first reference embodiment of the present invention. Multicore optical amplifier 102 in the present reference embodiment, interleaver 109 1568.77 nm (191.10 THz) from 1608.33 nm (186.40 THz) to be arranged at spaced at 100 GHz the 48-wave WDM signal between (WDM signal -L1) 1569.18 nm ( 46 WDM signals (WDM signal-L2) arranged at 100 GHz intervals from 191.05 THz to 1608.76 nm (186.35 THz) are multiplexed and demultiplexed by each core of the amplification fiber 103. However, the interleaver 109 arranged on the input side of the optical amplifier 102 combines the WDM signal -L1 input to the amplification core fiber 103 and the WDM signal -L2 output from the amplification fiber 103, and The interleaver 109 arranged on the output side combines the WDM signal -L1 output from the amplification fiber 103 and the WDM signal -L2 input to the amplification fiber 103. With this configuration, the WDM signal -L1 and the WDM signal -L2 propagate through the amplification fiber 103 in opposite directions and are amplified. For this reason, the number of wavelengths of the WDM signal propagating in one direction of the amplification fiber 103 is half that of the first embodiment, and the frequency interval is doubled. For this reason, crosstalk due to FWM is suppressed. As the amplifying fiber, doping concentration and multicore fiber parameters Er is the fiber absorption loss at 1530 nm is set to be 12 dB / m and an optical amplifier of this reference embodiment with reference 80m first embodiment As a result of comparing the maximum FWM crosstalk in the optical amplifier of the first embodiment, the FWM crosstalk was −38 dB in the optical amplifier of the first embodiment, whereas the FWM crosstalk was −43 dB in the optical amplifier of the reference embodiment. The crosstalk suppression effect was confirmed. Further, it is understood that the optical amplifier of this preferred embodiment is effective in reducing the optical amplifier size. Table 3 shows a comparison of the number of components between the conventional multi-core optical amplifier and the optical amplifier of the present embodiment. In this reference embodiment, the number of components can be reduced to about 84% of the conventional number.

( Third embodiment)
FIG. 13 shows a third embodiment of the present invention. In the optical amplifier 102 of the present embodiment, an interleaver 109 in the input / output unit is connected to the excitation / signal multiplexer / demultiplexer 105. Six interleavers 109 and six pump / signal multiplexers / demultiplexers 105 provided on the input side and output side of the optical amplifier 102, respectively, are integrated as a single quartz-based planar lightwave circuit (PLC). Has been. The optical isolator 106 is disposed between the fan-out 107 and the interleaver 109 so that the interleaver 109 and the multiplexer / demultiplexer 105 are integrated in the PLC. The transmission multi-core fiber 101, the amplification fiber 103, the excitation light source 104, and the fan-outs 107 and 108 are the same as those in the first embodiment. In this embodiment, the interleaver and the multiplexer / demultiplexer are integrated in the PLC, so that the interleaver and the pump / signal multiplexer / demultiplexer used in the optical amplifier of the first embodiment can be more easily downsized. It becomes. Furthermore, further miniaturization is possible by using an interleaver and an excitation / signal multiplexer / demultiplexer integrated with a silicon optical integrated circuit. In addition, the integration of the interleaver and the excitation / signal multiplexer / demultiplexer is not limited to the integration in the waveguide, but the interleaver components (eg, lens, prism, mirror, GT etalon) and the excitation / signal multiplexing / demultiplexing. Components that contain wave components (for example, lenses, dielectric multilayer filters, etc.) in a single package can also be integrated into bulk components because the pigtail fiber connection required when using individual components can be omitted. effective. Table 4 shows a comparison of the number of components between the conventional multi-core optical amplifier and the optical amplifier of the present embodiment. In the present embodiment, the number of components can be reduced to about ½ of the conventional number.

1,101 Multicore fiber for transmission 2,20,102 Optical amplifier 3,30,103 Amplifying fiber 4,104 Excitation light source 5,105 Excitation / signal multiplexer / demultiplexer 6,106 Optical isolator 7, 8, 107, 108 Fan Out 9,109 Interleaver 11, 12, 21, 23, 111, 112, 121, 122 Core

Claims (5)

An optical amplifier as an optical repeater, and a transmission multicore fiber having a plurality of cores as a transmission line, in a plurality of adjacent cores of the transmission multicore fiber, in either one of the C band and the L band A multi-core optical transmission system for transmitting a plurality of WDM signals having different wavelength arrangements,
The optical amplifier is
At least one set of interleavers including an interleaver that inputs and multiplexes a plurality of WDM signals having different wavelength arrangements respectively propagating through different cores among adjacent cores of the multicore fiber for transmission ;
At least one set of multiplexer / demultiplexers including a multiplexer / demultiplexer that combines the plurality of multiplexed WDM signals and the pump light from the interleaver;
An amplification fiber having at least one core doped with rare earth ions,
Each of the sets of multiplexers / demultiplexers of the at least one set of multiplexers / demultiplexers is connected to one of at least one core of the amplification fiber to amplify the plurality of multiplexed WDM signals. A multi-core optical transmission system characterized by being configured to do so. The number of sets of the at least one set of interleavers and the at least one set of multiplexers / demultiplexers is two or more,
The number of cores of the amplification fiber having the at least one core is plural,
The optical amplifier is
And a set of fan-outs for connecting each of the sets of multiplexers / demultiplexers of the at least one set of multiplexers / demultiplexers to one of the plurality of cores of the amplification fiber. The multi-core optical transmission system according to claim 1. 3. The multi- core optical transmission system according to claim 1, wherein the number of cores of the amplification fiber is smaller than the number of cores of the transmission multi-core fiber connected to an input / output of the optical amplifier. Each of the at least one set of multiplexers / demultiplexers is connected to the one set of fan-outs so that the propagation direction of the signal light is opposite in the adjacent cores of the plurality of cores of the amplification fiber The multi-core optical transmission system according to claim 2 or 3. 4. The multi-core optical transmission system according to claim 1, wherein two WDM signals are propagated and amplified in opposite directions in the same core of the amplification fiber.

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