WO2004091123A1 - 光増幅機能を有する光通信システム - Google Patents
光増幅機能を有する光通信システム Download PDFInfo
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- WO2004091123A1 WO2004091123A1 PCT/JP2004/004664 JP2004004664W WO2004091123A1 WO 2004091123 A1 WO2004091123 A1 WO 2004091123A1 JP 2004004664 W JP2004004664 W JP 2004004664W WO 2004091123 A1 WO2004091123 A1 WO 2004091123A1
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- optical
- light
- optical fiber
- station
- signal
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
- H04B10/2912—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form characterised by the medium used for amplification or processing
- H04B10/2916—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form characterised by the medium used for amplification or processing using Raman or Brillouin amplifiers
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
Definitions
- Optical communication system having optical amplification function
- the present invention relates to an optical communication system in which a master station and a slave station are connected by an optical fiber.
- the present invention relates to an optical communication system, in particular, connecting a master station and an optical branch station having a passive optical splitter with a trunk optical fiber, and connecting a branch line between the optical branch station and a plurality of slave stations. It relates to a P 0 N (Passive Optical Network) system connected by optical fibers.
- P 0 N Passive Optical Network
- P0N Passive Optical Network
- PDS Passive Double Star
- an optical amplifier is inserted into an optical fiber between a master station and a plurality of slave stations.
- an optical amplifier is used, it is costly to obtain and install the optical amplifier, and if a failure occurs after installation, it is necessary to go to the installation location of the optical amplifier, which requires a lot of maintenance.
- the amplification function can be distributed to optical fibers without using a single optical amplifier, maintenance becomes easier and cost reduction due to mass production can be expected.
- an object of the present invention is to provide an optical communication system capable of giving an optical fiber an optical amplification function.
- the wavelength of a signal light source that generates downstream signal light is set to a wavelength that has an effect of Raman-amplifying an upstream optical signal propagating through an optical fiber. While the transmitted upstream optical signal propagates through the optical fiber, the upstream optical signal is amplified.
- the signal light source is used to generate signal light having a wavelength that has the effect of amplifying the upstream optical signal, and is transmitted to the slave station through the optical fiber. This makes it possible to easily amplify the upstream signal light transmitted through the optical fiber.
- the selection of the master station and the slave station is optional, and the master station may be provided with a wavelength signal light source having an effect of Raman amplification.
- Figure 15 is a graph showing Raman amplification conditions.
- the horizontal axis represents wavelength, and the vertical axis represents optical power during propagation. It is assumed that the signal light and the amplification light propagate in opposite directions.
- the wavelength of the amplification light should be about 0.1 m shorter than the wavelength of the signal light.
- the Raman gain (g R / Aeff) P p Leff is 0.1 dB or more.
- (g R / Aeff) is the Raman gain coefficient of the optical fiber
- P p is the Bon Pink power input to the optical fiber
- Leff is the effective distance along the optical fiber on which the bombing light acts.
- a highly nonlinear fiber for at least a part of the optical fiber (claim 2).
- Raman gain (g R / A) eff) An optical fiber with P p L eff of 4 dB or more.
- P p L eff of 4 dB or more.
- it can be manufactured by making the core diameter slightly smaller than that of a general single mode optical fiber. If a highly nonlinear fiber is used, a strong nonlinear effect can be obtained, so that the amplification gain of the optical signal can be increased. Therefore, the upstream signal can be amplified even if the power of the signal light source that generates the downstream signal light is relatively weak or the distance is short.
- the term “at least part” is used because it is not necessary to use a highly nonlinear fiber for the entire transmission line, but only for a distance sufficient to obtain the required amplification gain.
- a highly nonlinear fiber and a SMF Single Mode Fiber
- a portion near the signal light source of the master station is connected to a highly nonlinear fiber, It is effective if the part is composed of SMF.
- the on state and the off state fluctuate even when data code 0 continues, and the on state and off state even when code 1 continues. It is preferable to use a modulation method whose state fluctuates (claim 3). In this case, since the ON state does not continue for a long time and the OFF state does not continue for a long time, fluctuations in amplification gain can be suppressed, and stable amplification characteristics can be obtained. In particular, if the ratio of the ON state and the OFF state is constant, it is effective to suppress the amplification gain fluctuation.
- the length of the portion where the upstream signal light is amplified is longer than the length of the optical fiber corresponding to the set of the ON state and the OFF state of the downstream signal light (Claim 4).
- an optical signal propagates through an optical fiber having a length (m) at a speed cZn (in / sec).
- c is the speed of light in a vacuum
- n is the effective refractive index of the optical fiber.
- the length of the optical fiber is L (m).
- the master station be provided with an optical filter for selecting the wavelength of light incident on the light receiving element (claim 5).
- the wavelength of a signal light source that generates downstream signal light is set to a wavelength that has the effect of Raman-amplifying an upstream optical signal propagating through a trunk optical fiber. While the upstream optical signal transmitted between the slave stations propagates through the trunk optical fiber, the upstream optical signal is amplified (Claim 6).
- the signal light source is used to generate signal light having a wavelength that has the effect of amplifying the upstream optical signal, and is distributed to the slave stations through the trunk optical fiber and the optical multiplexer / demultiplexer. This makes it possible to easily amplify the signal light while transmitting the trunk optical fiber.
- the upstream signal light transmitted through the optical fiber can be dispersed and amplified by propagating the downstream signal light.
- Raman amplification is used as the function of amplifying the optical signal
- the upstream signal light transmitted through the optical fiber can be dispersed and amplified by propagating the downstream signal light.
- a highly non-linear fiber for at least a part of the trunk optical fiber. If this highly nonlinear fiber is used, a strong nonlinear effect can be obtained, and a high gain can be obtained with relatively weak amplified light. Therefore, the light power of the signal light source may be relatively low.
- a highly nonlinear fiber and a single mode fiber (SMF) are connected in series, and the part close to the signal light source of the master station is connected to the high nonlinear fiber, and the far part is connected. It is more effective to use SMF.
- the modulation method for turning on and off the downstream signal light varies between the on state and the off state even when the code 0 of the data continues, and the on / off state varies even when the code 1 continues.
- the modulation method is used (claim 8)
- the Raman amplification can be performed on the optical signal in the ON state, so that a stable amplification characteristic can be obtained.
- a method of modulating the polarization or phase of the signal light is used, Since the optical power hardly changes over time, stable amplification can always be performed without regard to the encoding method.
- the length of the portion where the upward signal light is amplified in the self-main trunk optical fiber corresponds to the set of the on-state and the off-state of the downstream signal light.
- the distance is longer than the length of the fiber (claim 9).
- a signal light source and an optical multiplexer / demultiplexer are installed in the master station, and the signal light is passed through the optical multiplexer / demultiplexer from the master station to the optical branching station with a trunk optical fiber. If it is injected into the base station, the upstream optical signal can be amplified between the master station and the optical branch station (claim 10). Since the optical signal from the slave station passes through a long propagation path, and the distance between the master station and the optical branch station is often long, amplification of the optical signal during this period is effective.
- a star coupler can be used as a passive optical splitter (Claim 11; FIG. 4). According to this configuration, manufacturing and management costs can be reduced by using an inexpensive star coupler. Also, since all slave stations can handle optical signals of the same wavelength, manufacturing costs of slave stations can be reduced.o
- a passive optical splitter uses a Suzuichi coupler for downstream signal light, and multiplexes and splits upstream signal light by using a difference in wavelength for upstream signal light.
- AWG that can be used can be used (Claim 12; FIG. 5).
- the upstream signal light can be multiplexed and demultiplexed with low loss, allowing more room for designing the optical power of the signal light source of the slave station.
- the PON system of the present invention comprises: an amplification light source that generates amplification light having a wavelength that has an effect of amplifying an optical signal propagating through an optical fiber (including a trunk optical fiber and a branch optical fiber); An optical multiplexer / demultiplexer for injecting the optical signal into the optical fiber, wherein the optical signal is amplified while the optical signal transmitted between the master station and the slave station propagates through the optical fiber in the optical fiber. Things (Claim 13).
- the amplification light source is used to generate amplification light having a wavelength that has the effect of amplifying the optical signal, and is injected into the optical fiber through the optical multiplexer / demultiplexer.
- the signal light transmitted through the optical fiber can be easily amplified.
- the signal light transmitted through the optical fiber can be dispersed and amplified by propagating the amplification light in the opposite direction to the signal light (claim 14). Can be.
- a highly nonlinear fiber as an optical fiber for realizing Raman amplification (Claim 15). If this highly nonlinear fiber is used, a strong nonlinear effect can be obtained, and a high gain can be obtained with relatively weak amplified light.
- a highly nonlinear fiber and a single mode fiber (SMF) are connected, and a portion near the light source for amplification is composed of a highly nonlinear fiber and a portion far away is composed of an SMF. It is effective.
- an erbium-doped fiber (EDF) is used as a function to amplify an optical signal in addition to Raman amplification (claim 16), the same as the amplification light can be obtained by using the guided emission of erbium ions. The signal light in the direction can be amplified.
- EDF erbium-doped fiber
- the amplifying light is unmodulated light, a more stable amplification of four elements can be obtained.
- a light source for amplification and an optical multiplexer / demultiplexer are installed in the master station, and the amplification light is injected into the trunk optical fiber from the master station to the optical branching station, so that the optical signal is transmitted between the master station and the optical branching station. It can be amplified (Claim 17; FIG. 6). Since the optical signal from the slave station passes through a long propagation path, and the distance between the master station and the optical branch station is often long, amplification of the optical signal during this period is effective.
- a light source for amplification and an optical multiplexer / demultiplexer are installed in the optical branch station, and the amplification light is injected into the trunk optical fiber from the optical multiplexer / demultiplexer toward the master station.
- the signal can be amplified (Claim 18; FIG. 7).
- a second optical multiplexer / demultiplexer, and a third optical multiplexer / demultiplexer are installed in the optical branching station, and the amplification light transmitted through the trunk optical fiber for the upstream signal is transmitted to the second optical multiplexer. It can be taken out of the optical multiplexer / demultiplexer, supplied to the third optical multiplexer / demultiplexer through the optical path, and injected from the third optical multiplexer / demultiplexer to the master optical fiber for downstream signals toward the master station. 9; FIG. 8).
- the downstream signal light can be amplified by re-injecting the amplification light transmitted from the master station through the upstream signal trunk optical fiber into the downstream signal trunk optical fiber toward the master station.
- the upstream signal light and the downstream signal light have the same wavelength, it is possible to efficiently amplify both the upstream and downstream signals with one amplification light source.
- an amplification light source and an optical multiplexer / demultiplexer are installed in the master station, and the amplification light is injected from the master station into the trunk optical fiber toward the optical branch station. If a reflector that totally reflects the linear optical fiber is provided (Claim 21; FIG. 10), the optical signal can be transmitted by the amplification light source provided in the master station without providing the amplification light source in the optical branch station. Can be amplified.
- the reflector can be realized by, for example, FBG (Fiber Bragg Grating).
- An amplification light source and an optical multiplexer / demultiplexer are installed in the master station, the amplification light is injected from the master station into the trunk optical fiber toward the optical branch station, and the second optical multiplexer / demultiplexer is injected into the optical branch station. It is also possible to adopt a configuration in which a reflector is installed, amplification light transmitted through the trunk optical fiber is extracted from the second optical multiplexer / demultiplexer, and is totally reflected by the reflector (claim 22; FIG. 11). .
- the optical signal can be amplified by the amplification light source provided in the master station without providing the amplification light source in the optical branch station.
- An optical multiplexer / demultiplexer is installed at the optical branching station, an optical fiber is provided between the master station and the optical branching station, in addition to the trunk optical fiber, the light source for amplification is installed at the master station, and the light for amplification is installed at the master station. And supplying the light for amplification to the optical multiplexer / demultiplexer through the optical fiber.
- a configuration is also possible in which the optical fiber is injected into the trunk optical fiber from the device toward the master station.
- a star coupler can be used as a passive optical splitter (claim 24). By using cheap star couplers, manufacturing and management costs can be reduced.
- An optical fiber other than the trunk optical fiber is provided between the master station and the optical branching station, the amplifying light source is installed in the master station, and the amplifying light is transmitted through the optical fiber to the slave station side of the optical multiplexer / demultiplexer. It is also possible to adopt a configuration in which light is injected toward the master station in one optical path (Claim 25; FIG. 13).
- the optical multiplexer / demultiplexer can be obtained by the passive optical splitter. Therefore, there is no need to prepare an optical multiplexer / demultiplexer separate from the passive optical branching device, and the configuration of the optical branching station is simplified.
- an AWG capable of multiplexing and splitting light of different wavelengths can be used as an optical branching station. Item 26). By using AWG, amplified light can be separated with low loss.
- FIG. 1 is a block diagram showing an optical communication system having an optical amplification function according to the present invention.
- FIG. 2 is a network configuration diagram showing a connection state between the optical line terminal 0LT of the master station 1 and the optical network unit ONU of the slave station 5.
- FIG. 3 is a block diagram showing an entire PON system having an optical amplification function according to the present invention.
- FIG. 4 is a configuration diagram showing a PON system of the present invention that amplifies an upstream signal transmitted through a trunk optical fiber by using a signal High LD for a master station.
- FIG. 5 is a configuration diagram showing a PON system of the present invention in which a star coupler is used for downstream signal light and AWG is used for upstream signal light to multiplex and demultiplex signal light.
- FIG. 6 is a configuration diagram showing a PON system of the present invention in which an amplifying LD is installed in a master station to amplify an upstream signal propagating through a trunk optical fiber and a branch optical fiber.
- FIG. 7 is a configuration diagram showing a PON system of the present invention in which an amplification LD is also installed in an optical branch station to amplify a downlink signal from a master station.
- Fig. 8 is a block diagram showing the P0N system of the present invention that can amplify the upstream signal to the master station and the downstream signal from the master station only by installing one LD for amplification in the master station. It is.
- FIG. 9 is a configuration diagram illustrating a configuration of a PON system in which an upstream optical signal is amplified from a slave station to a master station by the light of the amplification LDb installed in the optical branch station, in addition to the configuration of FIG.
- FIG. 10 shows two amplifiers LD2 and LD3 installed in the master station, the downstream signal propagating in the trunk optical fiber is amplified by the light of LD2, and the main and branch optical fibers are amplified by the light of LD3.
- FIG. 2 is a configuration diagram showing a P 0 N system of the present invention that can amplify an uplink signal propagating through the P0N.
- FIG. 11 shows the installation of two amplification LDs 2 and 3 in the master station, amplifying the downstream signal propagating through the trunk optical fiber with the light of LD 2, and the main and branch optical fibers with the light of LD 3.
- FIG. 2 is a configuration diagram showing a P 0 N system of the present invention that can amplify an uplink signal propagating through the P0N.
- Fig. 12 shows a P0N system of the present invention in which two amplification LDs 1 and 2 are installed in a master station and can amplify upstream and downstream signals propagating through a trunk optical fiber. It is a block diagram.
- FIG. 13 shows two main amplifiers LD1 and LD2 installed in the master station.
- FIG. 1 is a configuration diagram showing a PON system of the present invention capable of amplifying upstream and downstream signals propagating through a receiver.
- FIG. 14 is a perspective view showing the structure of the WDMF.
- FIG. 15 is a graph showing conditions of Raman amplification wavelength versus optical power.
- FIG. 1 is a block diagram showing an optical communication system having an optical amplification function according to the present invention.
- the component of the optical communication system in the station building is called “master station”, and the component of the optical communication system in the relay station is called “slave station”.
- the optical communication system includes a master station 1, a slave station 5, an optical branch station 6, and a subscriber's house 7, and the master station 1 and the slave station 5 are connected by an optical fiber 2.
- the optical fiber 2 uses a single mode fiber.
- Each of the master station 1 and the downstream transmission signal to the slave station 5 and the upstream transmission signal from the slave station 5 to the master station 1 are each composed of a bucket.
- the master station 1 receives the packet sent from the upper network (such as the Internet), sends it out to the slave station 5 through the optical network, receives the bucket sent from the slave station 5, and It has the function of sending out to networks.
- the upper network such as the Internet
- the master station 1 includes a media converter (Media Converter) serving as a connection end to an optical fiber, a layer 2 switch, a broadband access router serving as a connection end of an upper network, and the like.
- Media Converter Media Converter
- the slave station 5 includes a media converter (Media Converter) for transmitting and receiving broadband signals to and from an optical network, an optical transmission line terminator 0LT (Optical Line Terminals), and the like.
- Media Converter Media Converter
- 0LT Optical Line Terminals
- the subscriber home 7 includes a personal computer PC installed in the home, an optical network unit (ONU) for transmitting and receiving broadband signals from the personal computer PC to the optical network, and the like.
- ONU optical network unit
- the operation of the optical communication system will be briefly described.
- the master station 1 For a downstream bucket entering the master station 1 from a higher-level network, the master station 1 performs a predetermined process on the layer 2 switch. Then, it is transmitted to the optical network through the media converter.
- the optical signal transmitted to the optical network is transmitted to the slave station 5, which captures the optical signal and decodes and decodes the bucket.
- the upstream bucket transmitted from the slave station 5 is transmitted to the master station 1.
- the data is transmitted to a higher-level network via a broadband access router.
- a method is employed in which even if the state of data 0 or 1 continues for a long time, it does not shift to a high level or a low level. For example, if the data is 0, a Manchester code that inverts from the high level to the low level at the center of the bit and if the data is 1 is inverted from the low level to the high level at the center of the bit, use a Manchester code. Can be. Further, when the NRZ code is adopted, the same effect can be obtained by adding a redundant bit to the original data and using a method of performing conversion so that 0s and 1s do not continue.
- FIG. 2 is a network configuration diagram showing a connection state between the media converter of the master station 1 and the media converter of the slave station 5.
- a high-power signal laser diode (High LD) is installed in the media converter of the master station 1, and the light is used to amplify the upstream signal from the slave station 5 to the master station 1.
- the media converter of the master station 1 includes a laser diode (High LD; transmission wavelength of 1.4 m) for a downstream signal and a light receiving diode (PD; reception wavelength of 1.5 zm) for an upstream signal. ing.
- the High LD and the PD are connected to the optical fiber 2 through a Wavelength Division Multiplexing Filter (WDMF).
- WDMF Wavelength Division Multiplexing Filter
- a bandpass optical filter BPF that allows only the wavelengths to be received to pass is added to the PD.
- the WDMF has waveguides 61 and 62 inserted in a dielectric substrate 60 and a dielectric multilayer film filter 6 3 provided at the contact portion of the waveguides 61 and 62. 4664
- the range of the reflected wavelength ⁇ 1 and the range of the transmitted wavelength 2 can be set by designing the dielectric multilayer filter 63.
- the media converter of the slave station 5 has a laser diode for upstream signals (LD for signals; transmission wavelength 1.5 m), a photodiode for downstream signals (PD; reception wavelength 1,4 xm), WDMF, and BPF. are doing.
- LD laser diode for upstream signals
- PD photodiode for downstream signals
- WDMF reception wavelength 1,4 xm
- BPF BPF
- the light having a wavelength of 1.4 mm from the High LD of the master station 1 passes through the WDMF, passes through the optical fiber 2, passes through the WDMF and BPF of the media converter of the slave station 5, and is received by the PD.
- the light from the sub-station 5 code word LD passes through the WDMF and enters the media converter of the master station 1 via the optical fiber 2.
- the light for the upstream signal is reflected by the WDMF in the master station 1 and received by the PD of the master station 1.
- the light of 1.4 m wavelength from the High LD of the master station 1 is about 0.1 yam shorter than the light of 1.5 m wavelength for the upstream signal. Can be amplified.
- HN LF high nonlinearity fiber
- SMF SingleModeFiber
- the optical fiber 2 has a length of 100 km, and the 4 km section near the media converter of the master station is composed of HNLF, and the 96 km section near the optical branch station is composed of SMF.
- the propagation loss of HNLF is 0.7 dBZZ at 1.4 ⁇ wavelength and 1.
- the propagation loss of the SMF is 0.4 dB / km at a wavelength of 1.4; am and 0.2 dB / km at a wavelength of 1.5.
- the received optical power at the slave station's media converter is 18.2 dBm.
- the received power of the up signal received at the P D of the master station is 124.2 dBm.
- the Raman gain of the highly nonlinear part of the optical fiber 2 is 11.6 dB and the Raman gain of the SMF part is 1.2 d B.
- the High LD of the master station's media converter does not always emit light.
- the 1000BASE-LX optical signal uses the NRZ code. Even in this state, since the encoding is performed so that the number of 0 bits and the number of 1 bits are almost equal, the light emission time can be regarded as about half. Then, the Raman gain of the HN LF of the optical fiber 2 is about half, 8.8 dB, and the Raman gain of the SMF is about half, 0.6 dB.
- the PD reception power of the master station's media converter is 14.8 dBm, which is obtained by adding (8.8 + 0.6) dB to 14.2 dBm. This is a level at which the media converter of the master station can receive with sufficient margin.
- FIG. 3 is a block diagram showing a PON system having an optical amplification function according to the present invention.
- the component of the PON system inside the station building is called the “master station”, and the component of the PON system inside the subscriber premises is called the “child station”.
- the PON system includes a master station 1, a plurality of slave stations 5, and an optical branch station (also referred to as a remote node) 3.
- the main station 1 and the optical branch station 3 are connected by a single-core trunk optical fiber 2.
- the branch optical fiber 4 is connected between the optical branching station 3 and the plurality of slave stations 5 respectively.
- the trunk optical fiber 2 and the branch optical fiber 4 are collectively called “optical fibers”.
- the optical fiber uses a single mode fiber.
- the downlink transmission signal from the master station 1 to the slave station 5 and the uplink transmission signal from the slave station 5 to the master station 1 are each constituted by a bucket.
- the master station 1 receives the packet sent from the upper network (such as the Internet), sends it out to the slave station 5 through the optical network, receives the bucket sent from the slave station 5, and It has the function of sending to
- the master station 1 includes an optical transmission line terminator 0 LT (Optical Line Terminals) serving as a connection end to an optical fiber, a layer 2 switch, a broadband access router serving as a connection end of a higher-level network, and the like. I have.
- optical transmission line terminator 0 LT Optical Line Terminals
- the slave station 5 includes a personal computer PC installed in the home, an optical network unit ONU (Optical Network Unit) for transmitting and receiving a broadband signal of the personal computer PC to and from the optical network. I have.
- ONU Optical Network Unit
- the master station 1 For a downstream bucket entering the master station 1 from a higher-level network, the master station 1 performs predetermined processing on the layer 2 switch. Then, the signal is transmitted to the optical network through the optical line terminal OLT. The optical signal transmitted to the optical network is branched at the optical branching station 3 and transmitted to some or all of the slave stations 5 connected to the optical branching station 3. The optical signal is captured, and the bucket is decrypted and decoded.
- the upstream bucket transmitted from the slave station 5 passes through the optical branching station 3 to the parent bucket. Sent to station 1.
- the data is transmitted to a higher-level network via the broadband access router.
- a method is employed in which even if the state of data 0 or 1 continues for a long time, it does not shift to a high level or a low level. For example, if the data is 0, a Manchester code that inverts from the high level to the low level at the center of the bit and if the data is 1 is inverted from the low level to the high level at the center of the bit, use a Manchester code. Can be. Further, when the NRZ code is adopted, the same effect can be obtained by adding a redundant bit to the original data and converting the original data so that 0s and 1s do not continue.
- FIG. 4 is a network configuration diagram showing a connection state between the optical transmission line termination device 0LT of the master station 1 and the optical subscriber line termination devices 0NU of the optical branching station 3 and the slave station 5.
- a high-power signal laser diode (High LD) is installed in the OLT to amplify the upstream signal from the optical branch station 3 to the master station 1.
- the optical transmission line termination OLT has a laser diode (High LD; transmission wavelength of 1.4 ⁇ ) for a downstream signal and a light receiving diode (PD; reception wavelength of 1.5 m) for an upstream signal.
- High 1_0 and High 1_0 are connected to the trunk optical fiber 2 through a WDMF (Wavelength Division Multiplexing Filter).
- WDMF Widelength Division Multiplexing Filter
- the WDMF has a structure in which waveguides 61 and 62 are provided in a dielectric substrate 60 in a mold, and a dielectric multilayer filter 63 is formed at the contact points of the waveguides 6 and 62.
- the light of wavelength U propagating in the waveguide 62; U is reflected at the contact portion, and the light of wavelength ⁇ propagating in the waveguide 61 passes through the contact portion.
- the range of the wavelength ⁇ 1 to be reflected and the range of the wavelength ⁇ 2 to be transmitted can be set by designing the dielectric multilayer filter 63.
- the optical line terminal NU of the slave station 5 is a laser diode (LD for signal; transmission wavelength and light-receiving diode (PD; It has a receiving wavelength of 1.4 ym).
- LD laser diode
- PD light-receiving diode
- the optical branching station 3 includes a star coupler for optical multi / demultiplexing, which connects the trunk optical fiber 2 and the branch optical fiber 4.
- Light having a wavelength of 1.4 1 ⁇ from the High LD of the master station 1 passes through the WDMF, passes through the trunk optical fiber 2 and enters the optical branch station 3, where it is split into a plurality (for example, 32) by the star coupler.
- the light is demultiplexed, propagated to the branch optical fiber 4, and received by the PD of the optical network unit 0NU of each slave station 5.
- the light from the signal LD of the slave station 5 enters the optical branching station 3 through the branch optical fiber 4, where it is multiplexed by the star coupler 1, passes through the main optical fiber 2, and passes through the optical transmission line of the master station 1.
- the light for the upstream signal is reflected by the WDMF in the OLT and received by the PD of the master station o.
- the light having a wavelength of 1.4 Atm from the High LD of the master station 1 has a wavelength of about 0.1 yam shorter than the light having a wavelength of 1.5 Atm for the upstream signal, the light having a wavelength of 1.5 m for the upstream signal is transmitted through the trunk optical fiber 2. Can be amplified.
- the upstream optical signal can be more effectively amplified by configuring the main optical fiber 2 on the master station side, for example, for 3 km with a highly nonlinear fiber and the remaining part with a single mode fiber (SMF). it can.
- SMF single mode fiber
- Raman amplification When Raman amplification is used, high-power signal light is required and safety considerations are required.However, in this configuration, the amplified light is attenuated by the transmission line and the star coupler, so general subscribers touch it. The power of the signal light at the subscriber's house and the 0 NU where the possibility is high is attenuated by + minutes, so that safety considerations are unnecessary or simple.
- the main spring optical fiber 2 is assumed to be 12 km, the 3 km section near the 0 L T is composed of highly nonlinear fiber, and the section 9! ⁇ 171 near the optical branch station is composed of 31 ⁇ 1.
- the branch optical fiber 4 is 4 km.
- the signal power becomes 10.2 dBm. If the Raman gain of the trunk optical fiber 2 is neglected, the received power of the uplink signal received by the P D of the master station is -24.6 dBm.
- the Raman gain of the high nonlinearity section of the trunk optical fiber 2 is calculated to be 6.8 dB, and the Raman gain of the SMF section is 0.75 d. B.
- the High L d of ⁇ LT does not always emit light.
- the 1000BASE-LX optical signal is searching for the NRZ code, but the original data consists of 8 bits of data plus 2 bits of redundant bits. Since the conversion is performed so that 0 and 1 do not continue, even if there is no signal, encoding is performed so that the number of 0 bits and the number of 1 bits are almost equal, so the emission time is regarded as about half Can be.
- the Raman gain of the highly nonlinear portion of the trunk optical fiber 2 is about half, 4.6 dB, and the Raman gain of the SMF portion is about half, 0.4 dB. Therefore, the PD received power at 0 LT of the master station becomes 19.6 dBm, in addition to the gain (4.6 + 0.4) dB at trunk optical fiber 2. This is a level at which the OLT can receive with a margin. When the OLT High LD light reaches 0 NU, the received power at the ONU is -3.8 dBm. This is the safest touch for subscribers.
- FIG. 5 is a network configuration diagram showing a connection state between the optical line terminal 0LT of the master station 1, the optical branching station 3, and the optical network unit 0NU of the slave station 5.
- 0LT is equipped with a high-power signal laser diode (High LD; transmission wavelength 1.4Atm) and a plurality of upstream signal light-receiving diodes (PD1 to PDN; reception wavelength 1.5 band).
- High LD high-power signal laser diode
- PD1 to PDN reception wavelength 1.5 band
- an AWG is installed to split the upstream signal light entering the OLT.
- the AWG and High LD are connected to trunk optical fiber 2 through WDMF.
- a WDM F and an AWG are installed in the optical branch station 3.
- the WDMF reflects the 1.4 m wavelength light from the High LD and supplies it to the star coupler.
- the star coupler sends down signal light to each ONU through the branch optical fiber 41.
- the AWG multiplexes the upstream signal propagating through the branch optical fiber 42 and sends it out to the trunk optical fiber 2.
- Light having a wavelength of 1.4 ⁇ from the High LD of the master station 1 passes through the WDMF, passes through the trunk optical fiber 2, and enters the optical branch station 3, where it is reflected by the WDMF and is multiplied by the star coupler (for example, 32), propagated to the branch optical fiber 41, and received by the PD of the optical network unit ON! U of each slave station 5.
- the star coupler for example, 32
- the light in the 1.5 m band from the 0 NU signal terminal of the slave station 5 enters the optical branch station 3 through the branch optical fiber 42, where it is wavelength-multiplexed by the AWG. (WDM) Then, it propagates through the trunk optical fiber 2 through the WDMF and enters the OLT of the master station 1.
- the light for the upstream signal is reflected by the WDMF in the OLT, further demultiplexed by the AWG for each wavelength, and received by any of PD1 to PDN of the master station 1.
- the wavelength of the upstream signal for the upstream optical fiber 2 is 1.5 m.
- the band light can be amplified.
- this configuration uses a low-loss AWG for multiplexing and demultiplexing the upstream optical signal, so that the power of the ONU signal LD can be reduced, and the subscribers who are likely to be touched by ordinary subscribers It is easier to secure safety at home and at 0 NU.
- the trunk optical fiber 2 is 2 O km
- the 3 km portion near the OLT is composed of a highly nonlinear fino
- the 17 km portion near the optical branching station is SMF.
- the lengths of the branch optical fibers 41 and 42 are 4 km.
- the signal power becomes 16.8 dBm.
- the received power of the uplink signal received by the P D of the master station is —19.7 dBm.
- the Raman gain of the high nonlinearity section of the trunk optical fiber 2 is calculated to be 6.8 dB, and the Raman gain of the SMF section is 0.84 d. B.
- the OLT High L d does not always emit light. Even if there is no signal, 1000BASE-LX optical signals are coded so that the number of 0 bits and the number of 1 bits are almost equal, so the light emission time is regarded as about half. Then, the Raman gain of the high nonlinearity part of the trunk optical fiber 2 is about half, 4.6 dB, and the Raman gain of the SMF part is about half, 0.4 dB.
- the PD reception power of the OLT of the master station becomes -14.7 dBm, in addition to the gain (4.6 + 0.4) dB at the trunk optical fiber 2. This is a level that can be received with a margin at 0 LT.
- the received power at the ONU is 17 dBm. This is a safe power that can be touched by subscribers.
- one bit or two bits can be encoded by a combination of one set of on-state and off-state depending on the data to be encoded. Then, there are 250 to 500 sets of combinations of the active state and the off state in the optical fiber. Approximately half are in the off state and about half are in the off state bit, so that about half the gain can be obtained in the Raman width over the entire optical fiber.
- 1000BASE-LX communication is performed by converting an 8-bit 'I blue report into 10 bits with redundancy at the physical layer.
- this code there are at least two on states and two off states, and the on and off states are arranged so that they are almost half each. Therefore, 1000BASE-LX requires at least two combinations of on-state and off-state to encode 8-bit information, with a few exceptions, depending on the information before and after. You can think. Since the transmission speed is 1 Mbit / s, the length of the optical fiber occupied by the 8-bit '
- FIG. 6 is a network configuration diagram showing a connection state between the optical line terminal 0 LT of the master station 1 and the optical network unit ONUs of the optical branching station 3 and the slave station 5.
- an amplification laser diode LD is installed in the OLT to amplify the upstream signal from the optical branch station 3 to the master station 1.
- the optical transmission line terminator 0 LT of the master station 1 has a laser diode for a downstream signal (LD for signal; transmission wavelength 1.3 m) and a laser diode for amplification of upstream signal (LD for amplification; transmission wavelength 1.4 Atm). It is equipped with a photodiode (PD; receiving wavelength 1.5 m) for upstream signals.
- the amplification LD and PD are connected to the trunk optical fiber 22 through a WDM F (Wavelength Division Multiplexing Filter).
- the optical network unit 0NU of the slave station 5 includes a laser diode for an upstream signal (LD for a signal; transmission wavelength of 1.5 Am) and a light receiving diode for a downstream signal (PD; a reception wavelength of 1.3 m).
- LD upstream signal
- PD downstream signal
- the optical branch station 3 connects the trunk optical fiber 21 and the branch optical fiber 41, connects the optical coupler 31 for optical demultiplexing, and connects the branch optical fiber 42 and the trunk optical fiber 22 to each other. It is equipped with a 32nd coupler for waves.
- the signal LD power of the master station 1 and the like pass through the main optical fiber 21 and enter the optical branch station 3, where it is split into a plurality (for example, 32) by the star coupler 31 and the branch light Each is connected to the fiber 41 and received by the PD of each slave station 5.
- the light from the signal LD of the slave station 5 enters the optical branch station 3 through the branch optical fiber 42, where it is multiplexed by the star coupler 32, passes through the trunk optical fiber 22, and passes through the main optical fiber 22. Enter the optical line termination OLT.
- the light for the upstream signal is reflected by the WDMF in the OLT and received by the PD of the master station 1.
- the light having a wavelength of 1.4 m emitted from the wide-width LD of the master station 1 passes through the WDMF, propagates through the trunk optical fiber 22, is further demultiplexed by the star power coupler 32, and is branched into the branch optical fiber 4 2 Is propagated. Since this 1.4 m wavelength light is about 0.1 m shorter than the 1.5 m wavelength upstream signal light, the 1.5 m wavelength upstream light can be amplified during this time.
- the station side portion of the trunk optical fiber 22 for 3 km, for example, with a highly non-linear fiber and the remaining portion with SMF, the signal light can be further effectively amplified.
- Raman amplification When Raman amplification is used, amplifying light of high power is required and safety considerations are required.However, in this configuration, the amplified light is attenuated by the transmission line and the star coupler, so general subscribers touch it. The power of the light for amplification at the subscriber's house and the 0 NU where the possibility is high has been sufficiently attenuated, and safety considerations are not required or simple considerations will be sufficient.
- the 0 LT PD reception power of the upstream signal reaching the master station is 1 29 dBm.
- the PD reception power of 0 LT of the master station becomes 16.9 dBm due to the addition of a gain of 2.1 dB at the trunk optical fiber '21.
- the received power at the slave station is 4 dBm. This is a safe power that can be touched by subscribers.
- FIG. 7 is a network configuration diagram showing a connection state between the optical transmission line terminating device 0LT of the master station 1, the optical branching station 3, and the optical network unit ONU of the slave station 5.
- an amplifying LD is also installed in the optical branching station 3 to amplify a downlink signal from the master station 1.
- an amplifying LD (transmission wavelength: 1.2; m) is installed in the optical branching station 3, and the amplified light from the amplifying LD is connected to the downstream trunk optical fiber 21 through WDMF. Have been.
- the signal light propagating through the downstream trunk optical fiber 21 from the OLT is reflected by the WDMF and enters the star coupler 31.
- the amplification light emitted from the amplification LD of the master station 1 passes through the WDMF and propagates through the trunk optical fiber 21 between the master station 1 and the optical branch station 3.
- the wavelength of the light for amplification, 1.2Am is about 0.1; m shorter than the light of 1.3Aim for the downstream signal, so the light for the downstream signal is amplified during this time. can do.
- the amplification LD is installed in the optical branching station.
- another station that is neither OLT nor the optical branching station can be prepared, and the amplification LD can be installed intensively there. It is.
- the amplification LD can be installed intensively there. It is.
- FIG. 8 is a network configuration diagram showing a connection state between the optical line terminal 0LT of the master station 1, the optical branching station 3, and the optical network unit 0NU of the slave station 5.
- the upstream signal to the master station 1 and the downstream signal from the master station 1 can be amplified simply by installing one amplification LD in the optical line terminal 0 LT of the master station 1.
- the configuration of the optical transmission line termination device 0 LT of the master station 1 is completely the same as that described with reference to FIGS. However, the difference is that the transmission wavelength of the LD for amplification is 1.2 m.
- two WDMFs are provided.
- One WDM Fa reflects the light from the 0 L T amplification LD and inputs it to the other WDMFb.
- the light input to the WDMFb reaches 0 LT through the downstream trunk optical fiber 21.
- the wavelength of the light for amplification is about 0.1 m shorter than the light of 1.3 m for the downstream signal, so that the light for the downstream signal can be amplified during this time.
- the light having a wavelength of 1.3 from the signal for the master station 1 is reflected by the WDMFb and enters the star coupler 131.
- the light of the LD for amplification of the master station 1 is passed through the two WDMFa and WDMFb of the optical branching station 3 to the downstream and upstream trunk optical fibers, so that the light from the master station 1 is transmitted.
- Downstream signals can be amplified.
- the upstream amplified light can be supplied by the amplifying LD of the master station 1, so that the downstream optical signal can be amplified while the optical branching station 3 is powered off.
- the upstream signal light has the same wavelength as the downstream signal light of 1.3 m, a single amplification LD can efficiently amplify both the upstream and downstream signals.
- two WDMFs and two star couplers are prepared for the optical branching station.
- the wavelength of the amplification light in the AWG is used. The same effect can be obtained by connecting the objects that correspond to each other.
- an optical signal is installed in the optical branch station 3 from the optical network unit 0 NU of the slave station 5 to the optical line termination 0 LT of the master station 1
- an amplification LDb (transmission wavelength: 1.2 m) is installed in the optical branching station 3, and the amplified light from the amplification LDb enters the star coupler 32 through the WDMF.
- the signal is demultiplexed and propagated to the branch optical fiber 42 to each slave station 5.
- the upstream signal (transmission wavelength 1.3 m) from the ONU signal LD is amplified by the amplified light in the branch optical fiber 42 while reaching the optical branch station 3.
- the WDMF and the 1: N star coupler are used, but the same effect can be realized only with the 2: N star coupler.
- the optical power is reduced by half, the cost and size can be reduced because the WDMF is not required.
- a single-mode optical fiber for transmitting an optical symbol in both directions is used.
- FIG. 10 is a network configuration diagram showing a connection state between the optical line terminal 0 L of the master station 1 and the optical network unit ONU of the slave station 5.
- two amplifiers 1_02 and LD3 are installed at the same position, and the LD2 light is transmitted to the downstream signal propagating through the trunk optical fiber 2 between the master station 1 and the optical branching station 3.
- the optical transmission line terminator 0 LT of the master station 1 has a laser diode for downstream signal (LD1 for signal; transmission wavelength 1.5 m) and a laser diode for amplification of downstream signal (LD2 for amplification; transmission wavelength 1.4 m). ) And a laser diode for amplifying the upstream signal. (LD3 for amplification; transmission wavelength 1.2yum), light receiving diode (PD; reception wavelength 1.3 ⁇ m), and three WDMFa to WDMFc.
- the light of the amplification LD2 is reflected by the first WDM Fa, reflected by the third WDMFc, and propagates through the trunk optical fiber 2 to the optical branching station 3.
- the light from the LD 3 for amplification passes through the second WDMFb and the third WDM Fc, and propagates through the trunk optical fiber 2 to the optical branching station 3.
- a band elimination type light passing filter FBG Fiber Bragg Grating 34 is introduced.
- This light-passing filter reflects light with a wavelength of 1.4 ym and passes light of other wavelengths. Therefore, the light having a wavelength of 1.4 m from the amplification LD2 is reflected and returns to the master station 1. As a result, the light having a wavelength of 1.5 Atm of the signal LD1 is amplified by the light having a wavelength of 1.4 yam of the amplification LD2 that has returned when propagating through the trunk optical fiber 2.
- the upstream amplified light can be supplied by the amplifying LD 2 of the master station 1, so that the downstream signal light can be amplified while the optical branching station 3 is powered off.
- the light having a wavelength of 1.2 / tm from the amplifying LD3 passes through the FBG 34, is demultiplexed by the star coupler 33 functioning as an optical multiplexer / demultiplexer, and transmitted through the branch optical fiber 4 to each slave station 5.
- the optical network unit 0NU of the slave station 5 includes a laser diode for an upstream signal (LD for a signal; transmission wavelength of 1.3 / m), a photodiode for a downstream signal (PD; a reception wavelength of 1.5 m), It is equipped with WDMF.
- the downstream signal propagating from the branch optical fiber 4 is reflected by the WDMF and sent to the PD.
- Light from the signal LD passes through the WDMF and propagates upward through the branch optical fiber 4.
- the upstream signal light from the signal LD is: Amplified while propagating through the branch optical fiber 4 between the optical branch station 3 and the slave station 5, and amplified while propagating through the trunk optical fiber 2 between the master station 1 and the optical branch station 3. .
- FIG. 11 shows the optical line terminal 0LT of the master station 1 and the optical subscriber line termination of the slave station 5.
- FIG. 3 is a network configuration diagram showing a connection state between end devices ONU.
- two amplification LDs 2 and LD3 are installed in the master station 1, and the LD2 light is used to amplify the downstream signal propagating through the trunk optical fiber 2 between the master station 1 and the optical branch station 3.
- the L3 light is used to amplify the upstream signal propagating through the trunk optical fiber 2 between the master station 1 and the optical branch station 3 and the branch optical fiber 4 between the optical branch station 3 and the slave station 5.
- the transmission wavelength of the laser diode L D1 for the downstream signal is 1.3 ⁇ m
- the reception wavelength of the photo diode PD is 1.5 zm
- the transmission wavelength of the amplification LD 2 is 1.2 / m m
- the transmission wavelength of the LD3 for amplification is 1.4y m
- the optical branching station 3 has WDMFd, a band reflection type optical reflection filter FBG34, and an optical fiber that connects both elements. 35 are installed.
- This WDMFd reflects light at a wavelength of 1.2 / m and passes light at other wavelengths.
- the light reflection filter FBG 34 totally reflects light having a wavelength of 1.2 / m reflected from the WDM Fd.
- the light having a wavelength of 1.2 mm from the amplification LD2 returns to the WDMFd, propagates through the trunk optical fiber 2, and returns to the master station 1.
- the 1.3-Atm wavelength light of the signal LD1 is amplified by the returned 1.2-nm wavelength light of the amplifying LD2 when propagating through the trunk optical fiber 2.
- the upstream amplification light can be supplied by the amplification LD 2 of the master station 1
- the downstream signal light can be amplified while the optical branching station 3 is not powered.
- the slave station 5 differs only in that the transmission wavelength of the upstream signal LD is 1.5 m and the reception wavelength of the downstream signal PD is 1.3 m, which is the reverse of FIG. 10.
- the 1.5-im wavelength upstream signal light from the signal LD is amplified by the 1.4-m wavelength light from the amplification LD3 while propagating through the branch optical fiber 4 between the optical branching station 3 and the slave station 5.
- the trunk optical fiber 2 between the master station 1 and the optical branch station 3 The light is also amplified by the light having a wavelength of 1.4 m from the LD 3 for amplification during the propagation of the light.
- the end face of the optical fiber 35 for transmitting the reflected light from the WDMFd may be subjected to reflection processing by metal film coating or the like. As a result, the light having a wavelength of 1.2 im reflected from WDMFd can be totally reflected.
- the amplification light is extracted by the WDMF in front of the star coupler.
- the port for extracting the amplification light is used.
- the same effect can be obtained by installing a device that totally reflects light (such as an FBG or an optical fiber whose end surface is processed to totally reflect light).
- FIG. 12 is a network configuration diagram showing a connection state between the optical transmission line terminating device 0 LT of the master station 1 and the optical network unit ONU of the slave station 5.
- two amplification LDs 1 and 2 are installed in the master station 1 to amplify the upstream and downstream signals that propagate through the trunk optical fiber 2 between the master station 1 and the optical branching station 3. I have.
- the optical transmission line terminator OLT of the master station 1 has eight laser diodes for signal (LD1 to D8 for signal; transmission wavelength of 1.5Atm band) and laser diode for downstream signal amplification (LD2 for amplification; transmission wavelength 1.4 m), laser diode for amplification of upstream signal (LD1 transmission wavelength for amplification 1.2yam), 8 light receiving diodes (PD1 to PD8; reception wavelength 1.3 1.3 band) and 2 It has an AWG (Arrayed-Wavelength Grating) and two WDMFs.
- the eight transmission signals are wavelength-division multiplexed (WDM) by the AWG and propagate through the main optical fiber.
- the received signal is demultiplexed for each wavelength by AWG and received by each PD.
- optical fiber 23 is independently provided between the master station 1 and the optical branching station 3.
- a WDM F and an AWG are installed in the optical branch station 3.
- WDMF reflects the 1.4 m wavelength light from the LD2 for amplification and passes other light.
- the AWG wave and the downstream signal that has propagated through the trunk optical fiber 2 are demultiplexed for each wavelength, and sent out to each ONU through the branch optical fiber 4. The operation of this configuration will be described.
- the light having a wavelength of 1.4 m of the LD2 for amplification reaches the optical branching station 3 through the optical fiber 23 provided independently, is reflected by the WDMF at the optical branching station 3, and propagates through the trunk optical fiber 2 in the upstream direction.
- the light having a wavelength of 1.2 m of the amplification LD1 passes through the two WDMFs and propagates down the trunk optical fiber 2 in the downstream direction.
- an optical signal in the 1.5 xm band emitted from one of the signal LD1 to D8 of the master station 1 (for example, signal LD1) is reflected by the WD MF through the AWG. , Go out the trunk optical fiber 2.
- the signal is amplified by the return light having a wavelength of 1,4 ym of the amplification LD2.
- the upstream amplified light can be supplied by the amplification LD 2 of the master station 1, the downstream signal light can be amplified while the optical branching station 3 is powered off.
- the light with a wavelength of 1.3 / m which exits from the slave station 5 and reaches the optical branch station 3, passes through the AWG and WDMF in the optical branch station 3, propagates through the trunk optical fiber 2, and reaches the master station 1. I do.
- the light propagates through the trunk optical fiber 2, the light is amplified by the light having a wavelength of 1.2 / m of the amplification LD1.
- both the upstream and downstream optical signals can be amplified by the amplification LD1 and LD2 light.
- FIG. 13 is a network configuration diagram showing a state of connection between the optical transmission line terminating devices 0 L T of the master station 1 and the optical subscriber line terminating devices ONU of the slave station 5.
- two amplification LD1 and LD2 are installed in the master station 1 and the upstream and downstream propagating the trunk optical fiber 2 between the master station 1 and the optical branching station 3. The signal is being amplified.
- the difference from FIG. 12 is that in the optical branching station 3, instead of installing the WDMF, the light of the amplification LD 2 propagating through the optical fiber 23 that is independently arranged is transmitted from the slave station 5.
- the AWG is entered into the AWG from one branch of the AWG's slave station 5 side.
- amplification light having a wavelength of 1.4 mm can be propagated toward the master station 1 to the main optical fiber 2 between the optical branching station 3 and the master station 1. Therefore, it is possible to amplify the downstream signal light having a wavelength of 1.5 m from the master station 1.
- the upstream amplified light can be supplied by the amplification LD 2 of the master station 1, so that the downstream signal light can be amplified while the optical branching station 3 is turned off.
- the embodiment of the present invention is not limited to the above-described embodiment.
- the ONU of the slave station is provided with the LD for the upstream signal and the PD for the downstream signal respectively.
- the LD for the upstream signal is omitted, and the light incident as the downstream signal is input. May be demultiplexed by a 3d ⁇ coupler and subjected to a modulation process for changing the wavelength (see JP-A-2001-177505) to be used as an upstream signal light.
- an optical filter may be installed in front of the light receiving diode PD.
- various changes can be made within the scope of the present invention.
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Abstract
Description
Claims
Priority Applications (4)
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AU2004228278A AU2004228278A1 (en) | 2003-04-02 | 2004-03-31 | Optical communication system having optical amplification function |
JP2005505225A JPWO2004091123A1 (ja) | 2003-04-02 | 2004-03-31 | 光増幅機能を有する光通信システム |
CA002521114A CA2521114A1 (en) | 2003-04-02 | 2004-03-31 | Optical communication system having optical amplification function |
US10/551,474 US20070014574A1 (en) | 2003-04-02 | 2004-10-21 | Optical communication system having optical amplification function |
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JP (1) | JPWO2004091123A1 (ja) |
KR (1) | KR20050114715A (ja) |
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JP2010252334A (ja) * | 2009-04-15 | 2010-11-04 | Ofs Fitel Llc | 両方向光通信ネットワークで分布ラマン増幅および遠隔ポンピングを使用する方法および装置 |
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2004
- 2004-03-31 WO PCT/JP2004/004664 patent/WO2004091123A1/ja active Application Filing
- 2004-03-31 AU AU2004228278A patent/AU2004228278A1/en not_active Abandoned
- 2004-03-31 JP JP2005505225A patent/JPWO2004091123A1/ja active Pending
- 2004-03-31 KR KR1020057018811A patent/KR20050114715A/ko not_active Application Discontinuation
- 2004-03-31 CA CA002521114A patent/CA2521114A1/en not_active Abandoned
- 2004-10-21 US US10/551,474 patent/US20070014574A1/en not_active Abandoned
Patent Citations (3)
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JP2001251252A (ja) * | 2000-03-03 | 2001-09-14 | Nippon Telegr & Teleph Corp <Ntt> | 光アクセス網、幹線ノード装置及び支線ノード装置 |
JP2002314177A (ja) * | 2001-04-12 | 2002-10-25 | Central Glass Co Ltd | 1.4〜1.52μm帯の光増幅器またはレーザー発振器の励起方法 |
JP2002314176A (ja) * | 2001-04-12 | 2002-10-25 | Central Glass Co Ltd | 1.4〜1.52μm帯の光増幅器またはレーザー発振器の励起方法 |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100767725B1 (ko) | 2006-04-05 | 2007-10-17 | 한국과학기술연구원 | 어븀 광섬유에서 증폭된 자기 발광 기반의 초광대역 광원발생기 및 이를 이용한 파장분할다중 수동광네트워크 |
JP2009141937A (ja) * | 2007-12-05 | 2009-06-25 | Korea Electronics Telecommun | 光学フィルタリング装置及び光通信システム |
JP2010010987A (ja) * | 2008-06-26 | 2010-01-14 | Fujikura Ltd | ラマン光増幅を用いた光伝送システム |
JP2010252334A (ja) * | 2009-04-15 | 2010-11-04 | Ofs Fitel Llc | 両方向光通信ネットワークで分布ラマン増幅および遠隔ポンピングを使用する方法および装置 |
JP2013176074A (ja) * | 2009-04-15 | 2013-09-05 | Ofs Fitel Llc | 両方向光通信ネットワークで分布ラマン増幅および遠隔ポンピングを使用する方法および装置 |
WO2012039133A1 (ja) * | 2010-09-24 | 2012-03-29 | 三菱電機株式会社 | 光伝送システム |
Also Published As
Publication number | Publication date |
---|---|
US20070014574A1 (en) | 2007-01-18 |
KR20050114715A (ko) | 2005-12-06 |
JPWO2004091123A1 (ja) | 2006-07-06 |
AU2004228278A1 (en) | 2004-10-21 |
CA2521114A1 (en) | 2004-10-21 |
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