KR20170130191A - Apparatus and method of suppression of back-reflection noise in SDM-WDM optical communication system using multi-core fiber - Google Patents

Abstract

A multi-core optical fiber-based space-wavelength division multiplexing optical network apparatus and a noise removing method thereof are disclosed. The space-wavelength division multiplexing optical communication network apparatus according to an embodiment of the present invention includes a light source for generating and outputting seed light for transmitting an upstream signal, and a space division multiplexing/demultiplexing unit for space-division multiplexing the output light of the light source, propagating the space-division multiplexed light to an optical fiber, space-division demultiplexing reflection light which is reflected and returned during propagation and transmitting the space-division demultiplexed light through a path which is different from the path of the upstream signal, thereby blocking the reflection. Accordingly, the present invention can prevent deterioration due to Rayleigh back scattering.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-core optical fiber based space-wavelength division multiplexing optical network device and a noise canceling method thereof,

The present invention relates to space division multiplexing-wavelength division multiplexing (SDM-WDM) optical communication system technology.

In a WDM (Wavelength Division Multiplexing) system, optical signals of various wavelengths are transmitted through a single optical fiber, and subscribers are independently allocated bandwidths using different wavelengths. There are various advantages such as ensuring the speed of up / down 100Mbps for each subscriber, securing a large transmission capacity, excellent scalability, and enhancing security of subscribers.

A WDM system is composed of a head end, a black link, and a plurality of tail ends. An incoherent light or a coherent light is emitted from a light source to an optical fiber Lt; / RTI > Such a light source injection based WDM system is capable of high-speed transmission and long-distance transmission and has a narrow channel spacing. However, performance is degraded due to back reflection, and the implementation cost of the system is large, which is not economical. In addition, wavelengths should be allocated and maintained for each subscriber.

According to one embodiment, when an injection-based WDM system using a single core optical fiber is upgraded to a multi-core optical fiber based large capacity WDM system, a multi-core optical fiber based space-time division multiplexing optical network device And a noise canceling method.

A space-time division multiplexing optical network apparatus according to an exemplary embodiment of the present invention includes a light source for generating and outputting seed light for uplink signal transmission, a spatial light modulator for propagating the output light of the light source to the multi-core optical fiber, And a spatial division multiplexer / demultiplexer for intercepting the reflected light as a result of spatial demultiplexing and transmitting the reflected light through a different path than the upstream signal.

The spatial division multiplexer / demultiplexer receives the output light of the light source through the first port, performs spatial division multiplexing on the output light, transmits the first multi-core optical fiber with the first reflected light, spatially demultiplexes the returned first reflected light, and outputs the first reflected light to the light source through the first port , An upstream signal modulated with a data signal to a wavelength injected from a light source can be space-demultiplexed and output through the second port.

The space-time division multiplexing optical network unit includes a wavelength division demultiplexer / demultiplexer for wavelength demultiplexing an upstream signal output from the spatial division multiplexer / demultiplexer, and a wavelength demultiplexer upstream signal in the wavelength division multiplexer / And an optical receiver for receiving the optical signal. The light source and the wavelength division multiplexer / demultiplexer may be N (N = k / 2) when the number of cores of the multicore optical fiber is k (k is a multiple of 2). Space-Wavelength Division Multiplexing Optical networks can have a N times increase in transmission capacity over a single wavelength division multiplexing optical network.

Space-wavelength division multiplexed optical network devices may be located at the head end. The light source may include a light interceptor for intercepting the reflected light received through the spatial division multiplexer / demultiplexer. The light blocking portion may be an optical isolator located at the output end of the light source. The reflected light may be a Rayleigh backscattering light.

Another spatial light modulator / wavelength division multiplexing optical network apparatus includes a wavelength division multiplexer / demultiplexer for wavelength division multiplexing an upstream signal in which a data signal is modulated with a wavelength injected by a light source, and an upstream signal output from the wavelength division multiplexer / demultiplexer A space division multiplexer / demultiplexer that spatially multiplexes the received optical signal and propagates to the multicore optical fiber and spatially demultiplexes the reflected light reflected back during the propagation, and receives the spatial demultiplexed reflected light from the spatial division multiplexer / demultiplexer And a blocking unit for blocking transmission to the wavelength division multiplexing / demultiplexing unit.

The blocking portion may be an optical circulator. The reflected light may be a Rayleigh backscattering light. The multi-core optical fiber may have k (k is a multiple of 2) cores, and the light source and the spatial division multiplexer / demultiplexer may be N (N = k / 2). The space-wavelength division multiplexing optical network device may be located in the black link stage.

A method of suppressing noise in a space-time division multiplexing optical communication network according to another embodiment includes injecting seed light of a light source into an optical transmitter through a multi-core optical fiber by space division multiplexing a seed light of a light source for upstream signal transmission, A step of spatially demultiplexing the first reflected light that is reflected and returned while the seed light is propagated to the optical fiber, and transmitting the first reflected light to the light source through a path different from the upward signal, thereby blocking the first reflected light.

The step of intercepting the first reflected light includes the steps of spatially demultiplexing the first reflected light through the first spatial division multiplexer / demultiplexer and outputting the first reflected light to the light source through the first port, Demultiplexing the modulated upstream signal through a first spatial division multiplexer / demultiplexer, and outputting the modulated upstream signal through a second port.

The noise cancellation method comprises the steps of wavelength-space division multiplexing an upstream signal modulated with a data signal from a light source to a wavelength injected from the light source and propagating the multi-core optical fiber to a multi-core optical fiber, and a step of spatially demultiplexing the second reflected light, And blocking the second spatially demultiplexed reflected light from being transmitted to the optical transmitter. The step of blocking transmission to the optical transmitter may block transmission using an optical circulator.

According to one embodiment, degradation due to Rayleigh back scattering can be solved when an injection based WDM system using single core optical fiber is upgraded to a multi-core optical fiber based large capacity WDM system. In particular, by simply modifying the structure, Rayleigh backscattering can be blocked to prevent noise from being generated fundamentally.

1 is a block diagram of an injection based WDM system,
FIGS. 2 and 3 are schematic diagrams of an injection-based WDM system for showing that Rayleigh back scattering occurs in a WDM system. FIG.
4 is a configuration diagram of a multi-core optical fiber based SDM-WDM system having k cores according to an embodiment of the present invention.
FIG. 5 is a configuration diagram of an SDM-WDM system using a multi-core optical fiber having two cores according to an embodiment of the present invention,
6 is a flowchart illustrating a noise removal method in a multi-core optical fiber based SDM-WDM system according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. , Which may vary depending on the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an injection based WDM system.

Referring to FIG. 1, the injection-based WDM system 1 is considered as a subscriber network capable of processing the continuously increasing network traffic most efficiently. When the WDM system 1 transmits a signal through a single mode optical fiber (SMF) 120, a C-band wavelength is used to transmit an upstream signal. And an L-band wavelength can be used when transmitting a downstream signal.

For example, when a C-band Seed Light Source (C-SLS) (hereinafter referred to as C-SLS) 100 of a head end 10 transmits a wide wavelength Coherent light or multi-mode coherent light having a band is output and propagated to the black link 12 via the optical circulator 102 and the C / L WDM filter 104. [ Is transmitted to several tens km of transmission SMF 120 and is spectrally divided into wavelengths allocated in an arrayed waveguide grating (AWG) 122. The C / L WDM filters 142-1 and 142-2 ..., 142-N to the optical transmitters (C-Tx) 140-1, 140-2, ..., 140-N of the respective channels.

The optical transmitters (C-Tx) 140-1, 140-2, ..., 140-N of the tail end 14 operate at the injected wavelengths and are output toward the head end 10 after the data signals are modulated. The data signal is multiplexed in the AWG 122 of the black link 12 and propagated through the transmission SMF 120. [ The signal is then demultiplexed by the AWG 106 through the optical circulator 102 and the two C / L WDM filters 104 and 105 of the head end 10 and the C / L WDM filters 107-1 and 107-2, ..., 107-N to the optical receivers (C-Rx) 109-1, 109-2, ..., 109-N.

On the other hand, in the case of a downstream signal, it is transmitted from the head end 10 toward the tail end 14 in the L-band wavelength. The downlink signal transmission process is a reverse process of the uplink signal transmission process, and a detailed description thereof will be omitted.

The above-described injection-based WDM system 1 with reference to FIG. 1 is not economical because the users of the tail end 14 are automatically assigned and operated by the head end 10 without having to adjust the assigned wavelengths. It is advantageous to construct.

FIGS. 2 and 3 are block diagrams of an injection-based WDM system for showing that Rayleigh back scattering occurs in a WDM system.

Referring to FIGS. 2 and 3, when the injection-based WDM system 1 transmits the upstream signal, the performance of the received signal is deteriorated by the two kinds of Rayleigh back scattering.

Figure 2 shows the first Rayleigh backscattering. The output light 200 of the C-SLS 100 of the head end 10 is propagated through the SMF 120 of several tens of km of the black link 12. At this time, a portion (BR-1) 210 of the light 200 to be propagated is reflected in a direction opposite to the propagation direction. That is, from the black link 12 toward the head end 10. This is because the light 200 propagated by the optical fiber impurity is backscattered due to the inherent characteristics of the optical fiber. The backscattered light 210 is beating with each other because the data signal is the same wavelength as the modulated light 220 in the optical transmitters (C-Tx) 140-1, 140-2, ..., 140- (C-RX) 109-1, 109-2, ..., 109-N of the optical receivers.

Figure 3 shows the second Rayleigh backscattering. The output light 300 of the C-SLS 100 of the head end 10 is propagated through the SMF 120 of the black link 12 several tens of kilometers and the optical transmitter 300 of the tail end 14 140-1, 140-2, ..., 140-N. The light 310 in which the data signal is modulated by the injected light 300 is transmitted upward toward the head end 10. At this time as well, reflection occurs in the direction opposite to the traveling direction of light in the transmission SMF 120. That is, the light (BR-2) 320 is reflected from the black link 12 to the tail end 14. The reflected light 320 is again injected into the optical transmitters (C-Tx) 140-1, 140-2, ..., 140-N of the tail end 14, The signal-modulated light 330 propagates again toward the head end 10.

In general, since the optical transmitters (C-Tx) 140-1, 140-2, ..., 140-N are constituted by elements for providing optical gain, the reflected light is amplified and output. Similarly, since the wavelength of the BR-2 320 is the same as the wavelength of the optical signal 330 output from the optical transmitters (C-Tx) 140-1, 140-2, ..., 140-N, C-Rx) 109-1, 109-2, ..., 109-N in the form of light intensity noise.

When the C-SLS (100) is used as a non-coherent light source, since the noise due to the Rayleigh back scattering exists over a wide frequency corresponding to the bandwidth of the light, the effect due to back scattering is not significant. However, when C-SLS (100) is used as a coherent light source, approximately 70% of beating noise due to Rayleigh backscattering exists in the low frequency band corresponding to the linewidth of the light source. This low-frequency noise degrades the quality of the signal.

There is a method of suppressing beating noise of 70% by introducing an electric low frequency cutoff frequency filter into the optical receivers (C-Rx) 109-1, 109-2, ..., 109-N of the head end 10. For this purpose, the signal modulation method dc can additionally include an 8b10b coding scheme not including a signal component or a Manchester code scheme. Here, there is an optimized cutoff frequency between noise suppression and signal distortion, and ultimately there is a limit to completely suppressing 70% of the noise. Since the remaining 30% of the beating noise can not be suppressed, the residual noise also has a significant influence on the transmission performance when the noise is very large.

On the other hand, in order to cope with the continuously increasing capacity, space division multiplexing (SDM) based multi-core optical fiber (MCF) in a single core optical fiber (SMF) , Hereinafter referred to as SDM) -WDM system is being considered. The present invention proposes a technique to solve the Rayleigh backscattering problem of the conventional injection-based WDM system while increasing the transmission capacity using the MCF. When the SDM-WDM is configured to increase the transmission capacity of the WDM system by N, the number of cores (k) of the MCF forming the black link should be doubled to N (k = 2 × N). That is, two cores of MCF are used to operate one WDM system. Hereinafter, an MCF-based SDM-WDM system having multicore according to an embodiment of the present invention will be described with reference to FIG. 4 and FIG.

4 is a block diagram of an MCF-based SDM-WDM system having k cores according to an embodiment of the present invention.

4, the SDM-WDM system 4 includes a head end 40, a black link 42, and a tail end 44. When the SDM-WDM system 4 is located in a passive optical network (PON), the head end 40 is a central office (CO) and the black link 42 is a remote node : RN), and the tail end 44 may be an optical network unit (ONU).

The head end 40 according to one embodiment includes an optical transmitter L-Tx 400-1, 400-2, ..., 400-n, an optical receiver C-Rx 401-1, 401-2, SLSs 407-1 to 407-N and the first AWGs 403-1 to 403-N, the C-SLSs 406-1 to 406-N, And a C / L WDM1 filter 402-1, ..., 402-N, and a C / L WDM1 filter 409. The spatial multiplexing / demultiplexing unit (SMUX / SDMUX) / L WDM2 filters 404-1 to 404-N, C / L WDM3 filters 405-1 to 405-N, and first optical circulators 408-1 to 408- . L-SLSs 407-1, ..., and 407-N are examples of seed light sources for upstream signal transmission, and L-SLSs 407-1 to 407-N are examples of seed light sources for downstream signal transmission. But is not limited thereto. The second AWGs 403-1, ..., and 403-N are examples of the wavelength division multiplexer / demultiplexer, but are not limited thereto.

Specifically, the C-SLSs 406-1, ..., and 406-N generate and output seed light for upstream signal transmission. The first SMUX / SDMUX 409 space-divides and multiplexes the output light of the C-SLSs 406-1,..., 406-N to the MCF 420. Then, the first reflected light is reflected and reflected in the middle of the propagation, receives the first reflected light, space-demultiplexes it, and transmits the first reflected light to the C-SLSs 406-1 through 406-N through a different path from the upward signal to block the first reflected light . For example, the first SMUX / SDMUX 409 transmits the first SPDM light to the C-SLSs 406-1, ..., (k-1) through the odd-numbered ports 1, , 406-N and spatial-demultiplexes an upstream signal modulated with a data signal with a wavelength injected from the C-SLSs 406-1, ..., 406-N to generate even-numbered ports 2, 4, ..., 406-N. , k-2, k). The first reflected light may be Rayleigh back scattered light.

The black link 42 includes an MCF 420, a second SMUX / SDMUX 421, a second optical circulator 422-1, ..., 422-N, and first AWGs 425-1, ), And may further include C / L WDM4 filters 423-1, ..., 423-N and C / L WDM5 filters 424-1, ..., 424-n. The first AWGs 425-1, ..., and 425-N are examples of the wavelength division multiplexer / demultiplexer, but are not limited thereto. The second optical circulators 422-1, ..., and 422-N serve to block the transmission of the second reflected light, and may be other components as long as they perform the same function. The second optical circulators 422-1, ..., and 422-N may be three-port optical circulators capable of transmitting light from the third port to the first port as shown in FIG. The second reflected light may be Rayleigh back scattered light.

Specifically, the uplink signals are transmitted from the first AWGs 425-1,..., 425-N to the second SMUX / SDMUX 421, are space division multiplexed and then propagated to the MCF 420. Then, the second reflected light reflected and returned during the propagation is space-demultiplexed. The second optical circulators 422-1 through 422-N receive the second reflected lights spatially demultiplexed from the second SMUX / SDMUX 421 and receive the first reflected lights from the first AWGs 425-1 through 425-N ). For example, the first AWGs 425-1, ..., and 425-N are connected through three-port optical circulators 422-1, ..., and 422-N, (C-Tx) 442-1, 442-2, ..., 442-n of the tail end 44 to prevent the second reflected light from being transmitted.

The tail end 44 includes optical transmitters (C-Tx) 442-1, 442-2, ... 442-n, optical receivers (L-Rx) 443-1, 443-2, ..., 443- L WDM6 filters 440-1, ..., 440-n.

Hereinafter, a process for removing noise including a reflected signal based on the configuration of the above-described SDM-WDM system 4 will be described.

In the case of downlink signal transmission using the L-band wavelength, the second AWGs 403-1, ..., 403-N of the head end 40 are connected to the C / L WDM3 filters 405-1, ..., 405- (K, 2, k) of the first SMUX / SDMUX 409 located at the first stage. The space-wavelength multiplexed optical signals pass through the MCF 420 of the black link 42 and are transmitted by the second SMUX / SDMUX 421 to the even-numbered ports 2,4, ..., k-2, Demultiplexed optical signal is output. The spatial demultiplexed optical signal passes through two C / L WDM4 filters 423-1 through 423-N and C / L WDM5 filters 424-1 through 424-N, The optical receiver L-Rx 443-n is wavelength-demultiplexed by the C / L WDM 6 filters 440-1, ..., 440-n of the tail end 44, 1, 443-2, ..., 443-n.

On the other hand, in case of upstream signal transmission using the C-band wavelength, the C-SLSs 406-1, ..., 406-N of the head end 40 are connected to the odd-numbered ports 1 SLM output light of the C-SLSs 406-1, ..., and 406-N is connected to the odd-numbered ports of the first SMUX / SDMUX 409 ( 1, 3, ..., (k-1), and is subjected to space division multiplexing in the first SMUX / SDMUX 409.

The C-SLS output light that has been space division multiplexed in the first SMUX / SDMUX 409 is propagated to the MCF 420 of the black link 42. The C-SLS output light is demultiplexed in the second SMUX / SDMUX 421 via the MCF 420 of the black link 42 and the demultiplexed C-SLS output light is output to the odd-numbered output port 1 of the second SMUX / SDMUX 421 , 3, ..., (k-1) and input to the second optical circulators 422-1, ..., and 422-N. Then, through the second optical circulators 422-1 through 422-N and the C / L WDM5 filters 424-1 through 424-N, the first AWGs 425-1 through 425-N And then transmitted to the tail end 44. [ And then injected into the optical transmitters (C-Tx) 442-1, 442-2, ..., 442-n through the C / L WDM6 filters 440-1, ..., 440-n of the tail end 44.

Thereafter, the optical transmitters (C-Tx) 442-1, 442-2, ..., 442-n of the tail end 44 operate with the injected C-SLS wavelengths to modulate the data signal and start the upstream signal transmission . At this time, the C / L WDM6 filters 440-1, ..., 440-n of the tail end 44 and the first AWGs 425-1, ..., 425- The WDM 5 filters 424-1 to 424-N, the second optical circulators 422-1 to 422-N and the C / L WDM4 filters 423-1 to 423-N , K-2, k of the second SMUX / SDMUX 421 and is then spread and multiplexed to the head end 40 through the MCF 420. [

Then, the first SMUX / SDMUX 409 of the head end 40 is spatially demultiplexed and the respective upstream signals are transmitted to the even-numbered ports 2, 4, ..., k-2, k . Subsequently, the second AWGs 403-1, ..., 403-N through the C / L WDM3 filters 405-1, ..., and 405- N and the upstream signals pass through the C / L WDM1 filters 402-1, ..., 402-n and the optical receivers C-Rx 401-1, 401-2, ..., 401-n ) Receives it.

5 is a configuration diagram of an SDM-WDM system using an MCF having two cores according to an embodiment of the present invention.

With reference to FIG. 5, an operation principle of the SDM-WDM system for completely blocking two Rayleigh backscattered lights as reflected light will be described. Since Rayleigh backscatter occurs during uplink signal transmission, downlink signal transmission is not considered. For the sake of clarity, consider a simple multi-core optical fiber with k = 2.

First Rayleigh backscattering light BR-1 (501) generated when the output light of the C-SLS 406 propagates from the head end 40 to the tail end 44 through the black link 42 Is returned to the C-SLS 406 and blocked. Since most of the light sources are equipped with optical isolators at the output end, the first Rayleigh back scattered light (BR-1) 501 can be completely blocked. Since the upstream signal modulated as described above in FIG. 4 is connected to the even port (for example, port 2 in FIG. 5) of the first SMUX / SDMUX 409 of the head end 40, It does not interfere with the scattered light (BR-1) 501.

The second Rayleigh backscattering light BR-2 502 generated when the light modulated with the data signal at the tail end 44 propagates to the head end 40 through the black link 42 is transmitted through the black link 42 SDMUX 421 of the second SMUX / SDMUX 421 and output to the even port (for example, port 2 of FIG. 5) of the second SMUX / SDMUX 421 and the C / L WDM4 filter 423, And is blocked without passing through the second optical circulator 422. The second optical circulator 422 may be a 3-port optical circulator capable of transmitting light from port 3 to port 1 as shown in FIG. At this time, the first port of the second optical circulator 422 is connected to the second SMUX / SDMUX 421, the second port is connected to the C / L WDM 5 filter 424, the third port is connected to the C / L WDM 4 filter 423, respectively. Similarly, the second Rayleigh backscattered light (BR-2) 502 can be blocked by the second optical circulator 422 as well.

6 is a flowchart illustrating a noise removal method in an MCF-based SDM-WDM system according to an embodiment of the present invention.

Referring to FIGS. 4 and 6, the SDM-WDM system 4 space-division multiplexes the seed light of the light source for transmission of an upward signal, and injects the seed light into the optical transmitter through the MCF 420 (610). At this time, the light source may generate incoherent light or incoherent light. The light source injected for upstream signal transmission may be a C-SLS.

The SDM-WDM system 4 then spatially demultiplexes the first reflected light reflected by the MCF 420 during the propagation of the seed light and transmits the first reflected light to the light source through a path different from the upward signal, (620). For example, the first SMUX / SDMUX 409 spatially demultiplexes the first reflected light and outputs the first reflected light to the light source through the first port. Then, an upstream signal modulated with a data signal with a wavelength injected from a light source is space-demultiplexed through a first SMUX / SDMUX 409 and output through a second port. The first reflected light may be Rayleigh back scattered light. The first port may be odd-numbered ports, and the second port may be even-numbered ports. Accordingly, since the first reflected light is connected to the port different from the upstream signal, interference with the upstream signal does not occur.

Then, the SDM-WDM system 4 wavelength-division-multiplexes the upstream signal modulated with the data signal with the wavelength injected from the light source, space-division multiplexes the wavelength division multiplexed upstream signal, and propagates the upstream signal to the MCF 420 (630) . At this time, the second reflected light reflected in the middle of the propagation is spatially demultiplexed and the second reflected light is transmitted to the optical transmitters (C-Tx) 140-1, 140-2, ..., 140-N (640). For example, the second optical circulator 422-1, ..., 422-N can be used to block transmission.

The embodiments of the present invention have been described above. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (17)

A light source for generating and outputting seed light for upward signal transmission; And
A spatial division multiplexer / demultiplexer for splitting the output light of the light source into a multi-core optical fiber, splitting the reflected light reflected in the middle of the propagation through a space different from the upstream signal, Multiplexer;
Wavelength division multiplexing optical network device. The apparatus of claim 1, wherein the spatial division multiplexer / demultiplexer
A first port for receiving the output light of the light source through a first port and performing spatial division multiplexing on the output light, transmitting the first reflected light to the multi-core optical fiber, outputting the first reflected light through the first port to the light source, Wavelength multiplexing optical network device according to claim 1 or 2, wherein the spatial multiplexing and demultiplexing of the upstream signal modulated with the data signal with the injected wavelength is performed through the second port. The apparatus of claim 1, wherein the space-time division multiplexing optical network unit
A wavelength division multiplexer / demultiplexer for wavelength demultiplexing an upstream signal output from the spatial division multiplexer / demultiplexer; And
An optical receiver for receiving a wavelength demultiplexed uplink signal in the wavelength division multiplexer / demultiplexer;
Further comprising a wavelength division multiplexing optical network device. The optical receiver as claimed in claim 3, wherein the light source and the wavelength division multiplexer / demultiplexer
(N = k / 2) when the number of cores of the multicore optical fiber is k (k is a multiple of 2). The apparatus of claim 1, wherein the space-time division multiplexing optical network unit
Wherein the optical fiber is located at the head end. The light source according to claim 1,
A light blocking unit for blocking reflected light received through the spatial division multiplexer / demultiplexer;
Wavelength division multiplexing optical network device. 7. The apparatus of claim 6, wherein the light blocking portion
Wherein the optical isolator is an optical isolator located at an output end of the light source. 2. The method of claim 1,
Rayleigh backscattered light. ≪ RTI ID = 0.0 > [10] < / RTI > A wavelength division multiplexer / demultiplexer for wavelength division multiplexing an upstream signal in which a data signal is modulated with a wavelength injected by a light source;
A spatial division multiplexer / demultiplexer for spatial multiplexing the upstream signals output from the wavelength division multiplexer / demultiplexer and then demultiplexing the reflected light reflected by the multi-core optical fiber during the propagation; And
Demultiplexer for receiving the spatially demultiplexed reflected light from the spatial division multiplexer / demultiplexer and blocking transmission to the wavelength division multiplexer / demultiplexer;
Wavelength division multiplexing optical network device. 10. The apparatus of claim 9, wherein the blocking portion
Wherein the wavelength division multiplexing optical network device is an optical circulator. 10. A method according to claim 9,
Rayleigh backscattered light. ≪ RTI ID = 0.0 > [10] < / RTI > 10. The method of claim 9,
Wherein the light source and the wavelength division multiplexer / demultiplexer have N (N = k / 2) when the number of cores of the multicore optical fiber is k (k is a multiple of 2) . 10. The apparatus of claim 9, wherein the space-time division multiplexing optical network device
Wherein the optical fiber is located at a black link end. A method for suppressing noise in a space-division multiplexed optical communication network,
A step of spatially dividing and multiplexing the seed light of the light source for transmission of the upward signal, and injecting the seed light into the optical transmitter through the multicore optical fiber; And
Blocking the first reflected light by spatially demultiplexing the first reflected light reflected by the multi-core optical fiber during the propagation of the seed light, and transmitting the first reflected light through the path different from the upstream signal to the light source;
And a noise canceling step. 15. The method of claim 14, wherein blocking the first reflected light comprises:
Demultiplexing the first reflected light through a first spatial division multiplexer / demultiplexer and outputting the first reflected light to the light source through a first port; And
Demultiplexing an upstream signal modulated with a data signal with a wavelength injected from the light source through the first spatial division multiplexer / demultiplexer, and outputting the upstream signal through a second port;
And a noise canceling step. 15. The method of claim 14,
Spreading an upstream signal modulated with a data signal to a wavelength injected from the light source into a multi-core optical fiber by wavelength-space division multiplexing;
Space-demultiplexing the second reflected light reflected and returned during the propagation; And
Blocking the transmission of the spatially demultiplexed second reflected light to the optical transmitter;
Further comprising the steps of: 17. The method of claim 16, wherein blocking the transmission to the optical transmitter comprises:
And the transmission is blocked by using the optical circulator.

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