WO2014201700A1 - 光线路终端、光网络单元、光网络系统及信号处理方法 - Google Patents

光线路终端、光网络单元、光网络系统及信号处理方法 Download PDF

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Publication number
WO2014201700A1
WO2014201700A1 PCT/CN2013/077699 CN2013077699W WO2014201700A1 WO 2014201700 A1 WO2014201700 A1 WO 2014201700A1 CN 2013077699 W CN2013077699 W CN 2013077699W WO 2014201700 A1 WO2014201700 A1 WO 2014201700A1
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WIPO (PCT)
Prior art keywords
optical
signal
light
sub
band
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PCT/CN2013/077699
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English (en)
French (fr)
Inventor
周雷
彭桂开
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to PCT/CN2013/077699 priority Critical patent/WO2014201700A1/zh
Priority to CN201380001486.4A priority patent/CN103733547B/zh
Publication of WO2014201700A1 publication Critical patent/WO2014201700A1/zh
Anticipated expiration legal-status Critical
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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
    • H04B10/50—Transmitters
    • H04B10/501—Structural aspects
    • H04B10/506—Multiwavelength transmitters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/03—WDM arrangements
    • H04J14/0305—WDM arrangements in end terminals

Definitions

  • the present invention relates to the field of network communication technologies, and in particular, to an optical line terminal, an optical network unit, an optical network system, and a signal processing method. Background technique
  • Passive Optical Network is a point-to-multipoint optical access technology that has gradually become a mainstream technology in the field of broadband access, along with various broadband services such as video conferencing, 3D TV, and mobile back.
  • PON Passive Optical Network
  • Typical PON systems include Optical Line Terminal (OLT), Optical Splitter (Splitter), Optical Network Unit (Optical Network Unit (ONU), wherein the optical beam splitter and the backbone optical fiber form an Optical Distribution Network (ODN), and the plurality of optical network units are connected to the optical beam splitter through the optical fiber, and are connected to the optical fiber through the trunk optical fiber after convergence.
  • the optical network unit shares the backbone fiber through TDMA.
  • Multi Band Frequency Multi Band Frequency
  • Multi-band FDM Division Multiplexing
  • the transmitting end ie, the optical line terminal
  • the transmitting end uses a bit loading algorithm, that is, transmitting a channel with a poor quality on a poor quality channel to turn off a poor quality channel.
  • Multi Band Transmission allows you to take full advantage of bandwidth.
  • this kind of electric multi-band FDM method requires a higher bandwidth of the radio frequency device, and such a radio frequency device has a frequency roll-off, which causes the performance of the radio frequency device to deteriorate at a high frequency, even if the electric multi-band FDM Complex channel estimation and bit loading algorithms are needed.
  • the object of the present invention is to provide an optical line terminal, an optical network unit, an optical network system and a signal processing method, which can transmit the baseband with the best transmission performance of the optical fiber and the radio frequency device, can overcome the high frequency attenuation caused by the dispersion of the optical fiber, and overcome each The photoelectric device has insufficient frequency response and roll-off at high frequencies.
  • a first aspect of the present invention provides an optical line terminal, where the optical line terminal includes: a laser, a combiner, an optical amplifier, a light modulator, a first optical fiber, and a second optical fiber; For generating direct current light;
  • the first optical fiber is connected to the laser and the combiner for exciting the direct current generated by the laser through stimulated Brillouin scattering SBS to form local oscillator and reverse transmission a first sub-wave, and the local oscillator is transmitted to the combiner; wherein the local oscillator is an optical signal whose optical power is less than an SBS threshold, and the first sub-wave is An optical signal in which direct light power is greater than an SBS threshold;
  • the optical amplifier is connected to the first optical fiber and the second optical fiber, and is configured to perform optical signal amplification processing on the first sub-wave, and transmit the amplified optical signal to the first Two optical fibers;
  • the second optical fiber is connected to the optical amplifier and the optical modulator, and is configured to excite the optical signal amplified by the optical amplifier by an SBS to form an optical carrier and a second sub-wave that is reversely transmitted. Transmitting the optical carrier to the optical modulator; wherein, the second sub-optical wave is an optical signal in which the optical power of the optical signal after the amplification process is greater than an SBS threshold, and the optical carrier is the amplification processing The optical signal in the latter optical signal having an optical power smaller than the SBS threshold;
  • the light modulator is connected to the second optical fiber and the combiner for modulating the optical carrier and the input downlink electrical signal to form signal light, and transmitting the signal light to the combiner;
  • the combiner is coupled to the first optical fiber and the optical modulator for using the first
  • the local oscillator light formed by the optical fiber and the signal light formed by the optical modulator combine to form an optical multi-band multiplexed signal and output.
  • the first optical fiber is connected to the laser by a first optical circulator, and the first end of the first optical circulator is The output end of the laser is connected, the second end of the first optical circulator is connected to the first optical fiber, and the direct current light generated by the laser is transmitted to the first optical fiber, the first A third end of the optical circulator is coupled to the input end of the optical amplifier, and transmits the first sub-optical wave formed by the first optical fiber to the optical amplifier.
  • the optical amplifier is connected to the second optical fiber by a second optical circulator, and the first end of the second optical circulator is An output end of the optical amplifier is connected, a second end of the second optical circulator is connected to the second optical fiber, and an optical signal amplified by the optical amplifier is transmitted to the second optical fiber.
  • the third end of the second optical circulator is connected to the next optical amplifier, and the second sub-wave formed in the second optical fiber is transmitted to the next optical amplifier.
  • the frequency difference between the first sub-waves formed in the first optical fiber and the direct current generated by the laser is ⁇ f
  • the frequency difference between the second sub-wave and the first sub-wave formed in the second fiber is ⁇ ⁇
  • the present invention further provides an optical network unit, where the optical network unit includes: a photo-electric receiver, a band-pass filter, and a demodulator;
  • the optoelectronic receiver is configured to receive an optical multi-band multiplexed signal sent by an optical line terminal, where the optical multi-band multiplexed signal includes a local oscillator light and a plurality of signal lights, where the signal light and the local oscillator light respectively Performing coherent mixing to obtain an electrical multi-band multiplexed signal;
  • the band pass filter is configured to perform band-pass filtering on the electrical multi-band multiplexed signal obtained by the optoelectronic receiver to obtain an electrical signal of a required frequency band, and transmit the signal to the demodulator for demodulation.
  • the present invention further provides an optical network system, where the optical network system includes: the optical line terminal according to the embodiment of the present invention, the optical network unit and the optical distribution network according to the embodiment of the present invention.
  • Network ODN the optical network system includes: the optical line terminal according to the embodiment of the present invention, the optical network unit and the optical distribution network according to the embodiment of the present invention.
  • the optical line terminal is connected to the optical network unit through the optical distribution network.
  • the present invention further provides an optical network signal processing method, the method comprising: transmitting, by a laser, direct current light in a first optical fiber, exciting by stimulated Brillouin scattering SBS, forming a local oscillator and a reverse a first sub-wave of the transmission; wherein the local oscillator is an optical signal whose optical power is less than an SBS threshold, and the first sub-wave is an optical signal whose optical power is greater than an SBS threshold;
  • the second sub-wave is an optical signal whose optical power is greater than an SBS threshold in the optical signal after the amplification process
  • the optical carrier is an optical signal whose optical power is less than an SBS threshold in the optical signal after the amplification process, the light
  • the carrier is used to modulate the input downlink electrical signal to form signal light
  • the local oscillator and the signal light combine to form an optical multi-band multiplexed signal, and output the optical multi-band multiplexed signal to the optical network unit.
  • a frequency difference between the first sub-light wave and the direct current light generated by the laser is A f
  • the second sub-wave wave and the first The frequency difference of a sub-wave is A f.
  • the method before the outputting the optical multi-band multiplexed signal to the optical network unit, the method further includes: multiplexing the multiple optical multi-band multiplexed signals In one way, the combined optical multi-band multiplexed signal is transmitted to the optical network unit through the optical fiber.
  • the present invention further provides an optical network signal processing method, where the method includes: receiving an optical multi-band multiplexed signal sent by an optical line terminal, where the optical multi-band multiplexed signal includes a local oscillator and multiple Signal light, wherein the signal light is coherently mixed with the local oscillator light to obtain an electrical multi-band multiplexed signal;
  • the optical line terminal, the optical network unit, the optical network system and the signal processing method provided by the invention generate the optical carrier with stable frequency interval between wavelengths by SBS excitation, so that all sub-band signals have the best transmission performance in the optical fiber and the radio frequency device.
  • the baseband transmits, so as to overcome the high frequency attenuation caused by the dispersion of the optical fiber, and overcome the insufficient frequency response and roll-off of various photoelectric devices at high frequencies.
  • FIG. 1 is a schematic structural diagram of an optical network system according to Embodiment 1 of the present invention.
  • FIG. 2a is a schematic diagram of an optical multi-band multiplexed signal output by an optical line terminal according to Embodiment 1 of the present invention
  • FIG. 2b is a schematic diagram of an electrical multi-band multiplexed signal output by an optoelectronic receiver according to Embodiment 1 of the present invention
  • FIG. 2c is a schematic diagram of a signal outputted by a band pass filter according to Embodiment 1 of the present invention
  • FIG. 3 is a schematic structural diagram of an optical network system according to Embodiment 2 of the present invention
  • FIG. 4 is a schematic structural diagram of an optical network system according to Embodiment 3 of the present invention.
  • FIG. 5 is a flowchart of a method for processing an optical network signal according to Embodiment 4 of the present invention
  • FIG. 6 is a flowchart of still another method for processing an optical network signal according to Embodiment 4 of the present invention. detailed description
  • the downlink mode of P0N is in broadcast mode, and the broadcast information is distributed to several user terminals through the optical beam splitter.
  • the optical line terminal, the optical network unit, the optical network system and the signal processing method provided by the embodiments of the present invention are compatible with the existing deployed P0N network (P0N based on the optical beam splitter), and are also applicable to other P0N structures, as follows
  • FIG. 1 is a schematic structural diagram of an optical network system according to this embodiment.
  • the optical network system includes: an optical line terminal 1, an optical beam splitter 2, and an optical network unit 3, and the plurality of optical network units 3 are connected to the optical beam splitter 2 through the optical fiber 4, and the optical beam splitter 2 passes through the trunk optical fiber 5 and the optical line The terminals 1 are connected.
  • the optical line terminal 1 includes: a laser 11, a first optical circulator 12, a first optical fiber 13, an optical amplifier 14, a second optical circulator 15, a second optical fiber 16, a light modulator 17, and a combiner 18.
  • the laser 11 is used to generate direct current light.
  • the laser 11 is connected to the first optical fiber 13 via a first optical circulator 12, and the first optical fiber 13 is used to illuminate the direct current ⁇ generated by the laser 11. Excited by stimulated Brillouin scattering SBS, forming a local oscillator and a reverse transmitted first sub-wave ⁇ ⁇
  • the first fiber 13 is also connected to the combiner 18, and transmits the local oscillator to the multiplexer 18.
  • the local oscillator is the direct current ⁇ .
  • the optical power of the medium optical power is less than the SBS threshold, and the first sub-wave human 1 is the direct current ⁇ .
  • the frequency difference is A f , and the magnitude of this frequency difference A f can be controlled.
  • the optical amplifier 14 is connected to the first optical fiber 13 through the first optical circulator 12, and is connected to the second optical fiber 16 through the second optical circulator 15 for the first one formed in the first optical fiber 13
  • the sub-wave ⁇ performs an optical signal amplification process, and transmits the amplified optical signal to the second optical fiber 16 through the second optical circulator 15.
  • the first end of the first optical circulator 12 is connected to the output end of the laser 11, and the second end of the first optical circulator 12 is connected to the first optical fiber 13 to generate the direct current generated by the laser 11. ⁇ . Transfer to the first fiber 1 3 .
  • the third end of the first optical circulator 12 is connected to the input end of the optical amplifier 14, and the first sub-waves formed by the first optical fiber 13 are exclusively transmitted to the optical amplifier 14.
  • the first end of the second optical circulator 15 is connected to the output end of the optical amplifier 14, and the second end of the second optical circulator 15 is connected to the second optical fiber 16, and the optical signal amplified by the optical amplifier 14 is transmitted to
  • the second optical fiber 16 and the third end of the second optical circulator 15 are connected to the next optical amplifier, and the second sub-waves formed in the second optical fiber 16 are transmitted to the next optical amplifier.
  • the second optical fiber 16 is connected to the optical modulator 17, and is configured to excite the optical signal amplified by the optical amplifier 14 through the SBS to form an optical carrier and a second sub-wave ⁇ 2 that is reversely transmitted, and transmit the optical carrier.
  • the light modulator 17 is supplied.
  • the second sub-wave ⁇ 2 is an optical signal in which the optical power of the optical signal after the amplification process is greater than the SBS threshold, and the optical carrier is the optical power of the optical signal after the amplification process is smaller than the SBS threshold. signal.
  • the optical modulator 17 is connected to the second optical fiber 16 and the combiner 18 for modulating the optical carrier formed in the second optical fiber 16 and the input downlink electrical signal to form signal light, and transmitting the signal to the combiner 18.
  • the combiner 18 is connected to the first optical fiber 13 and the optical modulator 17 for combining the local oscillator light formed by the first optical fiber 13 and the signal light formed by the optical modulator 17 to form an optical multi-band multiplexed signal and output , transmitted to the optical beam splitter 2 through the trunk fiber 5.
  • the optical beam splitter 2 splits the optical multi-band multiplexed signal to each optical network unit 3. That is, the signal light formed by each of the second sub-waves passes through the combiner 18 to the optical fiber and the optical beam splitter 2, and finally to each optical network unit 3.
  • the reverse-transmitted sub-waves formed in each fiber may be optically amplified and then excited by SBS to form a next sub-wave of frequency difference Af.
  • the second sub-optical wave formed by the second optical fiber 16 can be connected to the next optical amplifier through the second optical circulator 15, and the next optical amplifier passes through the next optical circulator and the next optical circulator.
  • the second fiber is connected, and the next second fiber is connected to the next light modulator.
  • the sub-waves ⁇ 4 , ⁇ 5 , ⁇ ⁇ can be sequentially generated by SBS excitation.
  • the frequency difference between all adjacent two sub-waves is A f .
  • a plurality of optical carriers can be generated, and a plurality of different downlink electrical signals can be modulated to form a plurality of signal lights, and the combiner 18 combines to form an optical multi-band multiplexed signal.
  • all the transmitted electrical signals are transmitted at the baseband with the best optical channel performance, and are respectively modulated by the optical modulator to the sub-waves ⁇ 1 ⁇ 2 , . . . ⁇ ⁇ . DC light ⁇ .
  • No modulation data, as local oscillator Light is sent to each optical network unit 3 for self-coherent reception to produce an electrical multi-band signal.
  • an optical multi-band frequency division multiplexed signal is formed on the optical line terminal, that is, all electrical signals are in the baseband, and a plurality of fixed sub-waves are separated to carry different baseband electrical signals.
  • the optical network unit 3 includes: a photoreceiver 31, a band pass filter 32, and a demodulator 33.
  • the photoreceiver 31 is for receiving an optical multi-band multiplexed signal transmitted by the optical line terminal 1.
  • the optical multi-band multiplexed signal includes a local oscillator light and a plurality of signal lights, and each of the signal lights is coherently mixed with the local oscillator light to obtain an electrical multi-band multiplexed signal.
  • the band pass filter 32 is configured to perform band-pass filtering on the electrical multi-band multiplexed signal obtained by the photoreceiver 31, obtain an electrical signal of a required frequency band, and transmit the signal to the demodulator 33 for demodulation to obtain an optical line terminal. 1 Received downlink signal.
  • the optical multi-band multiplexed signal as shown in FIG. 2a includes a plurality of signal lights having a spectral wavelength difference of A f , and each of the signal lights A f is usually small, generally not exceeding 10 GHz, and is subjected to coherent mixing.
  • a plurality of electrical signals having a frequency interval of Af on the electrical spectrum are obtained, as shown in Fig. 2b.
  • an electrical signal of a certain frequency band is obtained, as shown in Fig. 2c, an electrical signal with an intermediate frequency of 2 Af is obtained, which can be demodulated by the demodulator 33 according to the existing method.
  • the downlink signal received by the optical line terminal 1. This avoids various degradations in the transmission of electrical signals in the fiber.
  • the optical network unit 3 only needs to use the band pass filter (BPF) to filter out the required electric band for demodulation, which greatly reduces the complexity, power consumption and cost of the optical network unit.
  • BPF band pass filter
  • the embodiment of the invention provides an optical domain multi-band multiplexed passive optical network system, which uses fiber stimulated Brillouin scattering (SBS) to generate multiple sub-waves, each of which is in baseband mode on each optical carrier.
  • SBS fiber stimulated Brillouin scattering
  • Transmission that is, transmission at the baseband with the best transmission performance of fiber and RF devices, can overcome the high-frequency attenuation caused by fiber dispersion, and overcome the insufficient frequency response and roll-off of various photoelectric devices at high frequencies.
  • the frequency interval between the wavelengths of the generated light waves is stable, it is not affected by the laser wavelength jitter, and The sub-waves with narrow frequency intervals are generated with high precision, and the polarization states of the respective optical wavelengths are uniform, so that the multi-band multiplexed signals are obtained by completely coherent mixing in the receiving.
  • the nonlinear mixing noise between the sub-bands is reduced. Since the power of the local oscillator is high, the receiving sensitivity is also improved.
  • optical network units 3 and optical distribution networks have been deployed.
  • the optical distribution network 0DN can remain intact.
  • the optical network unit 2 is directly oriented to the end user.
  • it is necessary to maintain the cost and have sufficient advantages to smoothly upgrade the existing optical network system based on the optical splitter sp litter er while maintaining the 0DN. .
  • the invention can also be applied to a wavelength division multiplexing self-coherent passive optical network system.
  • the optical network system of the present invention includes: a plurality of optical line terminals 1, a plurality of optical network units 3, and an arrayed waveguide grating (AWG). , an arrayed waveguide grating 62 and an optical fiber 4 for connection.
  • the arrayed waveguide grating 61 connected to the plurality of optical line terminals 1 is connected to the arrayed waveguide grating 62 via the trunk optical fiber 5, and the arrayed waveguide grating 62 is connected to the plurality of optical network units 3.
  • each optical line terminal 1 is the same as that of the optical line terminal 1 in the first embodiment.
  • Each optical network unit 3 is the same as the optical network unit 3 in the first embodiment, and the specific processing procedure is the same. Narration.
  • the plurality of optical line terminals 1 are connected to the arrayed waveguide grating 61 via the optical fiber 4.
  • the input end of the arrayed waveguide grating 61 is connected to the combiner 13 of the plurality of optical line terminals 1 for transmitting the plurality of optical line terminals 1
  • the optical multi-band multiplexed signal is combined into a single fiber.
  • a plurality of optical network units 3 are connected to the arrayed waveguide grating 62 via an optical fiber 4, and a plurality of output ends of the arrayed waveguide grating 62 are respectively connected to the photoreceiver 31 of the optical network unit 3, so that the optical network unit 3 passes through the arrayed waveguide grating 62. Receiving an optical multi-band multiplexed signal transmitted by the optical line terminal.
  • the wavelength of the light of the direct current generated by the laser of each optical line terminal 1 is different, and the frequency difference of the wavelength of the light generated by the two optical line terminals 1 is usually much larger than the frequency difference between the sub-waves generated by the same laser through the SBS principle.
  • f in general, A f does not exceed 10 GHz, and the two optical lines end
  • the laser of terminal 1 produces a wavelength difference of up to 100 GHz.
  • the array waveguide grating 61 can be used to combine the optical signals of different wavelengths for transmission, and then the optical signals of different wavelengths can be separated by the arrayed waveguide grating 62.
  • the present invention can also be applied to a time division wavelength division passive optical network system in which an optical beam splitter and an arrayed waveguide grating coexist.
  • the optical network system of the present invention includes: a plurality of optical line terminals 1, an optical beam splitter 2, a plurality of optical network units 3, and an array.
  • the structure in this embodiment is similar to that in the second embodiment, except that in the optical network unit side, after the arrayed waveguide grating 62, the optical beam splitter 2 can be connected to each optical network unit 3, which can be improved. Access user density, extended access distance, suitable for multi-site fusion, to adapt to time-division, wavelength division multiplexing coexistence of passive optical network systems.
  • optical network system provided by the present invention.
  • optical network communication method provided by the present invention will be described in detail below.
  • FIG. 5 is a flowchart of a method for processing an optical network signal according to the embodiment. As shown in FIG. 5, on the optical line terminal side, the optical network signal processing method of the present invention includes:
  • the direct current light generated by the S10 laser is transmitted in the first optical fiber and excited by the SBS to form the local oscillator and the first sub-wave transmitted in the reverse direction.
  • the local oscillator is an optical signal whose optical power is less than an SBS threshold
  • the first sub-wave is an optical signal whose optical power is greater than an SBS threshold.
  • the frequency difference between the first sub-wave and the direct current generated by the laser is ⁇ f .
  • the principle of SBS When entering the laser ⁇ into the fiber. When the optical power reaches a certain value, due to SBS, the sub-wave (Stokers Stockes light wave) is excited. ⁇ Intrusion has the following characteristics: 1) ⁇ . With the reverse; 2) people with ⁇ . There is a certain frequency difference Af, which can be controlled; 3) Enter 1 with people.
  • the polarization state is the same; 4) If the person enters the fiber again, the power reaches the SBS domain value, and the next-order Stokes light ⁇ 2 is excited again, and the ⁇ 2 and the human frequency difference are still Af; 5) SBS in any Excited in the fiber, the excitation domain is lower in the high nonlinear fiber (HNF) with high nonlinear coefficient, and the required fiber length is very short.
  • HNF high nonlinear fiber
  • S1 02 performing optical signal amplification processing on the first sub-wave, and transmitting the amplified optical signal in a second optical fiber, and performing an SBS excitation to form an optical carrier and a second sub-wave that is reversely transmitted.
  • the optical carrier is used to modulate the input downlink electrical signal to form signal light.
  • the second sub-wave is an optical signal whose optical power is greater than an SBS threshold in the optical signal after the amplification process
  • the optical carrier is an optical signal whose optical power is less than an SBS threshold in the optical signal after the amplification process.
  • the frequency difference between the second sub-wave and the first sub-wave is A f.
  • S1 03 The local oscillator and the signal light combine to form an optical multi-band multiplexed signal, and output the optical multi-band multiplexed signal to the optical network unit.
  • the method before outputting the optical multi-band multiplexed signal to the optical network unit, the method further includes: combining the multiple optical multi-band multiplexed signals into one path, and transmitting the combined optical multi-band multiplexed signal through the optical fiber.
  • the plurality of optical multi-band multiplexed signals may be combined into one path by an arrayed waveguide grating, and then transmitted to the optical network unit side through the backbone optical fiber to reach each optical network unit.
  • FIG. 6 is a flowchart of still another method for processing an optical network signal according to the embodiment. As shown in FIG. 6, on the optical network unit side, the optical network signal processing method of the present invention includes:
  • the S20 receives the optical multi-band multiplexed signal sent by the optical line terminal, where the optical multi-band multiplexed signal includes a local oscillator light and a plurality of signal lights, where the signal light is coherently mixed with the local oscillator light to obtain electricity. Multi-band multiplexed signal.
  • the optical network unit may receive the optical multi-band multiplexed signal transmitted by the optical line terminal through the optical beam splitter, or may receive the optical multi-band multiplexed signal transmitted by the optical line terminal through the arrayed waveguide grating.
  • the optical multi-band multiplexed signal sent by the receiving optical line terminal includes:
  • the composite optical multi-band receives a plurality of optical line terminals to transmit a composite optical multi-band multiplexed signal, the composite optical multi-band The multiplexed signals are separated to obtain a single optical multi-band multiplexed signal.
  • the optical line terminal, the optical network unit, the optical network system and the signal processing method provided by the invention are excited by the fiber stimulated Brillouin scattering SBS, and the optical carrier with stable frequency interval between the wavelengths is obtained through the stepwise structure, and the light modulation is utilized.
  • the modulation and loading of the downlink electrical signal enables all sub-band signals to be transmitted in the baseband with the best transmission performance of the optical fiber and the RF device, thereby overcoming the high-frequency attenuation caused by the dispersion of the optical fiber, and overcoming the high-frequency of various photoelectric devices. Insufficient frequency response and roll-off.
  • the frequency interval between the wavelengths of the generated light waves is stable, and is not affected by the laser wavelength jitter, the sub-waves with narrow frequency intervals can be generated with high precision, and the polarization states of the respective optical wavelengths are uniform, ensuring complete coherent mixing in the receiving. Electrical multi-band multiplexed signal. At the same time, the nonlinear mixing noise between sub-bands is reduced during PD reception.
  • RAM random access memory
  • ROM read-only memory
  • EEPROM electrically programmable ROM
  • EEPROM electrically erasable programmable ROM
  • registers hard disk, removable disk, CD-ROM, or technical field Any other form of storage medium known.

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Abstract

本发明涉及一种光线路终端、光网络单元、光网络系统及信号处理方法，所述光线路终端包括：激光器、合波器、光放大器、光调制器、第一光纤和第二光纤；所述第一光纤，用于将所述激光器产生的所述直流光通过受激布里渊散射SBS激发，形成本振光和反向传输的第一子光波，并将所述本振光传输给所述合波器；所述第二光纤，用于将所述光放大器放大处理后的光信号通过SBS激发，形成光载波和反向传输的第二子光波，并将所述光载波传输给所述光调制器；所述合波器，用于将所述第一光纤形成的本振光与所述光调制器形成的信号光合波形成光多带复用信号并输出。本发明能够克服光纤色散引起的高频衰减，克服各种光电器件在高频处的频响不足、滚降。

Description

光线路终端、 光网络单元、 光网络系统及信号处理方法 技术领域
本发明涉及网络通信技术领域，尤其涉及一种光线路终端、光网络单元、 光网络系统及信号处理方法。 背景技术
无源光网络 ( Passive Optical Network, PON)是一种点对多点的光接 入技术， 在宽带接入领域逐渐成为主流技术， 随着各种宽带业务， 如视频会 议、 3D电视、 移动回传、 互动游戏等的快速发展， 对接入带宽的需求越来越 高。 面对未来的宽带演进， 需要更大的带宽、 长距离、 大分支。
目前大多数 P0N都是基于分时多址 ( Time Division Multiple Address, TDMA)方式,典型的 PON系统包括光线路终端（ Opt ical Line Terminal, OLT )、 光分束器（ Splitter ) 、 光网络单元（ Optical Network Unit, ONU ) , 其中， 光分束器与主干光纤构成光分配网络（ Optical Distribution Network, ODN), 多个光网络单元通过光纤连接到光分束器， 汇聚之后通过主干光纤连接到光 线路终端 （局端） 。 光网络单元通过 TDMA方式共享主干光纤。
现有的光网络系统大多采用多带频分复用 （Multi Band Frequency
Division Multiplexing, 多带 FDM )技术， 发送端 （即光线路终端）在电域 产生多带 FDM信号， 利用比特加载算法， 即在质量差的信道传输较少比特关 闭质量差的信道， 来进行多带传输（Multi Band Transmission) , 可以充分 利用带宽。
然而， 这种电多带 FDM方式需要较高的射频器件带宽， 这样的射频器件 存在频率滚降， 进而导致射频器件在高频处性能劣化严重， 即使电多带 FDM 需要采用复杂的信道估计与比特加载算法， 仍有很多高频部分由于频率衰减 严重， 无法得到利用， 对光滤波器的要求也很高。 发明内容
本发明的目的是提供一种光线路终端、 光网络单元、 光网络系统及信号 处理方法， 在光纤和射频器件传输性能最好的基带进行传输， 能够克服光纤 色散引起的高频衰减， 克服各种光电器件在高频处的频响不足、 滚降。
为实现上述目的， 本发明第一方面提供了一种光线路终端， 所述光线路 终端包括： 激光器、 合波器、 光放大器、 光调制器、 第一光纤和第二光纤； 所述激光器， 用于产生直流光；
所述第一光纤， 与所述激光器和所述合波器相连接， 用于将所述激光器 产生的所述直流光通过受激布里渊散射 SBS激发， 形成本振光和反向传输的 第一子光波， 并将所述本振光传输给所述合波器； 其中， 所述本振光为所述 直流光中光功率小于 SBS阈值的光信号， 所述第一子光波为所述直流光中光 功率大于 SBS阈值的光信号；
所述光放大器， 与所述第一光纤和所述第二光纤相连接， 用于对所述第 一子光波进行光信号放大处理， 并将所述放大处理后的光信号传输给所述第 二光纤；
所述第二光纤， 与所述光放大器和所述光调制器相连接， 用于将所述光 放大器放大处理后的光信号通过 SBS激发， 形成光载波和反向传输的第二子 光波， 并将所述光载波传输给所述光调制器； 其中， 所述第二子光波为所述 放大处理后的光信号中光功率大于 SBS阈值的光信号， 所述光载波为所述放 大处理后的光信号中光功率小于 SBS阈值的光信号；
所述光调制器， 与所述第二光纤和所述合波器相连接， 用于将所述光载 波与输入的下行电信号进行调制后形成信号光， 并传输给所述合波器；
所述合波器， 与所述第一光纤和所述光调制器相连接， 用于将所述第一 光纤形成的本振光与所述光调制器形成的信号光合波形成光多带复用信号并 输出。
结合第一方面， 在第一方面的第一种可能的实施方式中， 所述第一光纤 通过第一光环形器与所述激光器相连接， 所述第一光环形器的第一端与所述 激光器的输出端相连接，所述第一光环形器的第二端与所述第一光纤相连接， 将所述激光器产生的所述直流光传输给所述第一光纤， 所述第一光环形器的 第三端与所述光放大器的输入端相连接， 将所述第一光纤形成的所述第一子 光波传输给所述光放大器。
结合第一方面， 在第一方面的第二种可能的实施方式中， 所述光放大器 通过第二光环形器与所述第二光纤相连接， 所述第二光环形器的第一端与所 述光放大器的输出端相连接， 所述第二光环形器的第二端与所述第二光纤相 连接， 将所述光放大器放大处理后的光信号传输给所述第二光纤， 所述第二 光环形器的第三端与下一个所述光放大器相连接， 将所述第二光纤中形成的 所述第二子光波传输给下一个所述光放大器。
结合第一方面， 在第一方面的第三种可能的实施方式中， 所述第一光纤 中形成的所述第一子光波与所述激光器产生的直流光的频差为 Δ f ,所述第二 光纤中形成的所述第二子光波与所述第一子光波的频差为 Δ ί"。
第二方面， 本发明还提供了一种光网络单元， 所述光网络单元包括： 光 电接收器、 带通滤波器和解调器；
所述光电接收器， 用于接收光线路终端发送的光多带复用信号， 所述光 多带复用信号包括本振光和多个信号光， 所述信号光分别与所述本振光进行 相干混频， 得到电多带复用信号；
所述带通滤波器， 用于对所述光电接收器得到的所述电多带复用信号进 行带通滤波， 获取所需要频段的电信号， 并传输至所述解调器进行解调。
第三方面， 本发明还提供了一种光网络系统， 所述光网络系统包括： 本 发明实施例所述的光线路终端、 本发明实施例所述的光网络单元和光分配网 络 ODN;
所述光线路终端通过所述光分配网络与所述光网络单元相连接。
第四方面， 本发明还提供了一种光网络信号处理方法， 所述方法包括： 激光器产生的直流光在第一光纤中传输，通过受激布里渊散射 SBS激发， 形成本振光和反向传输的第一子光波； 其中， 所述本振光为所述直流光中光 功率小于 SBS阈值的光信号， 所述第一子光波为光功率大于 SBS阈值的光信 号；
对所述第一子光波进行光信号放大处理， 并将所述放大处理后的光信号 在第二光纤中传输， 通过 SBS激发， 形成光载波和反向传输的第二子光波； 其中， 所述第二子光波为所述放大处理后的光信号中光功率大于 SBS阈值的 光信号， 所述光载波为所述放大处理后的光信号中光功率小于 SBS阈值的光 信号， 所述光载波用于与输入的下行电信号进行调制后形成信号光；
所述本振光与所述信号光合波形成光多带复用信号， 并将光多带复用信 号输出给光网络单元。
结合第四方面， 在第四方面的第一种可能的实施方式中， 所述第一子光 波与所述激光器产生的直流光的频差为 A f ,所述第二子光波与所述第一子光 波的频差为 A f。
结合第四方面， 在第四方面的第二种可能的实施方式中， 所述将光多带 复用信号输出给光网络单元之前， 还包括： 将多路所述光多带复用信号复合 成一路， 将复合后的光多带复用信号通过光纤传送给光网络单元。
第五方面， 本发明还提供了一种光网络信号处理方法， 所述方法包括： 接收光线路终端发送的光多带复用信号， 所述光多带复用信号包括本振 光和多个信号光， 所述信号光分别与所述本振光进行相干混频， 得到电多带 复用信号；
对所述电多带复用信号进行带通滤波， 获取所需要频段的电信号， 并进 行解调处理得到所述光线路终端接收到的下行信号。 本发明提供的光线路终端、 光网络单元、 光网络系统及信号处理方法， 通过 SBS激发产生波长之间频率间隔稳定的光载波， 能使所有子带信号均在 光纤和射频器件传输性能最好的基带进行传输， 从而能够克服光纤色散引起 的高频衰减， 克服各种光电器件在高频处的频响不足、 滚降。 附图说明
图 1为本发明实施例一提供的光网络系统的结构示意图；
图 2a 为本发明实施例一提供的光线路终端输出的光多带复用信号示意 图；
图 2b 为本发明实施例一提供的光电接收器输出的电多带复用信号示意 图；
图 2c为本发明实施例一提供的一个带通滤波器输出的信号示意图； 图 3为本发明实施例二提供的光网络系统的结构示意图；
图 4为本发明实施例三提供的光网络系统的结构示意图；
图 5为本发明实施例四提供的一种光网络信号处理方法流程图； 图 6为本发明实施例四提供的又一种光网络信号处理方法流程图。 具体实施方式
下面通过附图和实施例， 对本发明的技术方案做进一步的详细描述。 无源光网络 P0N的下行模式均是采用广播模式， 通过光分束器将广播的 信息分配给若干个用户终端。 本发明实施例提供的光线路终端、 光网络单元、 光网络系统及信号处理方法， 可兼容现有已经部署的 P0N网络（基于光分束 器的 P0N ) , 同样适用于其他 P0N结构， 如下一代接入网结构： 波分复用无 源光网络 WDM P0N , 时分波分复用无源光网络 TWDM P0N等。
实施例一
图 1是本实施例提供的光网络系统的结构示意图， 如图 1所示， 本发明 的光网络系统包括： 光线路终端 1、 光分束器 2和光网络单元 3 , 多个光网络 单元 3通过光纤 4连接到光分束器 2 , 光分束器 2通过主干光纤 5与光线路 终端 1相连接。
光线路终端 1 包括： 激光器 11、 第一光环形器 12、 第一光纤 1 3、 光放 大器 14、 第二光环形器 15、 第二光纤 16、 光调制器 17和合波器 18。
激光器 11用于产生直流光。激光器 11通过第一光环形器 12与第一光纤 1 3相连接，第一光纤 1 3用于将激光器 11产生的直流光 λ。通过受激布里渊散 射 SBS激发， 形成本振光和反向传输的第一子光波 λ ΐ 第一光纤 1 3还与合 波器 18相连接， 并将所述本振光传输给合波器 18。 其中， 所述本振光为所 述直流光 λ。中光功率小于 SBS 阈值的光信号， 所述第一子光波人1为所述直 流光 λ。中光功率大于 SBS阈值的光信号。 第一光纤 1 3中形成的本振光与激 光器 11产生的直流光 λ。之间无频差， 第一光纤 1 3 中形成的第一子光波 与激光器 11产生的直流光 λ。的频差为 A f , 而且， 这个频差 A f 的大小可以 控制。
光放大器 14通过第一光环形器 12与第一光纤 1 3相连接，并通过第二光 环形器 15与第二光纤 16相连接，用于对第一光纤 1 3中形成的所述第一子光 波 λ 进行光信号放大处理， 并将所述放大处理后的光信号通过第二光环形器 15传输给第二光纤 16。
其中， 第一光环形器 12的第一端与激光器 11的输出端相连接， 第一光 环形器 12的第二端与第一光纤 1 3相连接，将激光器 1 1产生的所述直流光 λ 。传输给第一光纤 1 3。第一光环形器 12的第三端与光放大器 14的输入端相连 接， 将第一光纤 1 3形成的所述第一子光波人^专输给光放大器 14。
第二光环形器 15的第一端与光放大器 14的输出端相连接， 第二光环形 器 15的第二端与第二光纤 16相连接，将光放大器 14放大处理后的光信号传 输给第二光纤 16 , 第二光环形器 15 的第三端与下一个光放大器相连接， 将 第二光纤 16中形成的所述第二子光波传输给下一个光放大器。 第二光纤 16与光调制器 17相连接，用于将光放大器 14放大处理后的光 信号通过 SBS激发， 形成光载波和反向传输的第二子光波 λ 2, 并将所述光载 波传输给光调制器 17。其中， 所述第二子光波 λ 2为所述放大处理后的光信号 中光功率大于 SBS阈值的光信号， 所述光载波为所述放大处理后的光信号中 光功率小于 SBS阈值的光信号。第二光纤 16中形成的光载波与第一子光波 λ
！的之间无频差，第二光纤 16中形成的第二子光波 λ 2与第一子光波 λ！的频差 为 A f。
光调制器 17 , 与第二光纤 16和合波器 18相连接， 用于将第二光纤 16 中形成的所述光载波与输入的下行电信号进行调制后形成信号光， 并传输给 合波器 18。
合波器 18 , 与第一光纤 1 3和光调制器 17相连接， 用于将第一光纤 1 3 形成的本振光与光调制器 17形成的信号光合波形成光多带复用信号并输出， 通过主干光纤 5传输至光分束器 2。 光分束器 2将光多带复用信号分路给各 光网络单元 3。 也就是说， 每个第二子光波形成的信号光通过合波器 18进入 到光纤和光分束器 2，最终到达每个光网络单元 3。
需要说明的是， 本发明实施例中可对每一路光纤中形成的反向传输的子 光波进行光放大处理后再通过 SBS激发形成频差为 A f 的下一个子光波。 如 图中所示，第二光纤 16形成的反向传输的第二子光波可以通过第二光环形器 15与下一个光放大器相连接， 该下一个光放大器通过下一个光环行器与下一 个第二光纤相连接， 该下一个第二光纤与下一个光调制器相连接。依次类推， 可以通过 SBS 激发可以依次产生子光波 λ 4、 λ 5、 λ η。 所有相邻两个子光波 之间的频差都为 A f。 这样， 可以产生多个光载波， 可分别与输入的多个不同 的下行电信号进行调制后形成多个信号光，并经过合波器 18合波形成光多带 复用信号。
这样， 所有下发的电信号都在光信道性能最好的基带传输， 通过光调制 器分别调制到子光波 λ 1 λ 2、 . . λ η上。 直流光 λ。上不调制数据， 作为本振 光下发到每个光网络单元 3 , 以便进行自相干接收， 产生电多带信号。 这样， 在光线路终端上形成了光域多带频分复用信号，即所有电信号都在基带，依靠 多个相隔固定的子光波来承载不同的基带电信号。
光网络单元 3包括： 光电接收器 31、 带通滤波器 32和解调器 33。
光电接收器 31用于接收光线路终端 1发送的光多带复用信号。其中， 光 多带复用信号包括本振光和多个信号光， 各信号光分别与本振光进行相干混 频， 得到电多带复用信号。
带通滤波器 32用于对光电接收器 31得到的所述电多带复用信号进行带 通滤波， 获取所需要频段的电信号， 并传输至解调器 33进行解调， 得到光线 路终端 1接收到的下行信号。
直流光 λ。作为下行相干接收的本振光，在光电接收器 31产生相干混频。 由于本振光随下行信号一起发送，与信号具有相同的偏振态，又称为自相干接 收方法。 经过光电接收器 31 , 各信号光分别与所述本振光进行相干混频后， 得到电多带复用信号。如图 2a所示的光多带复用信号包括多个在光谱上波长 频差为 A f 的多个信号光， 每个信号光 A f 通常较小， 一般不超过 1 0GHz , 经 过相干混频后，得到在电频谱上频率间隔为 A f 的多个电信号，如图 2b所示。 再经过带通滤波器 32滤波后， 得到某个频段的电信号， 如图 2 c所示， 得到 中频在 2 A f 的电信号， 即可通过解调器 33按照现有方式进行解调得到光线 路终端 1接收到的下行信号。这样避免了电信号在光纤中传输时的各种劣化。 光网络单元 3只需用电带通滤波器（BPF)滤出自己所需要的电波段进行解调， 极大的降低了光网络单元的复杂度、 功耗以及成本。
本发明实施例提出一种光域多带复用的无源光网络系统， 利用光纤受激 布里渊散射（SBS )产生多个子光波， 每个子带都以基带的方式在每个光载波 上传输， 即在光纤和射频器件传输性能最好的基带进行传输， 能够克服光纤 色散引起的高频衰减， 克服各种光电器件在高频处的频响不足、 滚降。 而且， 由于产生的各光波波长之间频率间隔稳定， 不受激光器波长抖动影响， 能够 产生频率间隔很窄的子光波， 精度高， 各光波长偏振态一致， 保证在接收里 完全相干混频得到电多带复用信号。 同时， 在 PD接收时， 减小子带间的非线 性混频噪声。 由于本振光的功率较高， 还提高了接收灵敏度。
另外， 对于目前已经部署了大量的光网络单元 3和光分配网络。 在网络 升级过程中， 光分配网络 0DN可以保持不动。 光网络单元 2直接面向的是最 终用户， 在升级过程中， 需要保持成本具有足够优势， 可以在保持 0DN不动 时， 对现有的基于光分束器 sp l i t t er的光网络系统进行平滑升级。
实施例二
本发明还可以应用于波分复用自相干无源光网络系统中。
图 3是本实施例提供的光网络系统的结构示意图， 如图 3所示， 本发明 的光网络系统包括： 多个光线路终端 1、 多个光网络单元 3、 阵列波导光栅 ( AWG ) 61、 阵列波导光栅 62和用于连接的光纤 4。 与多个光线路终端 1相 连接的阵列波导光栅 61通过主干光纤 5与阵列波导光栅 62相连接， 阵列波 导光栅 62与多个光网络单元 3相连接。
每一个光线路终端 1的内部结构与实施例一中的光线路终端 1相同， 每 一个光网络单元 3与实施例一中的光网络单元 3相同， 具体的处理过程也相 同， 于此不再赘述。
多个光线路终端 1通过光纤 4与阵列波导光栅 61相连接，阵列波导光栅 61的输入端与多个光线路终端 1的合波器 1 3相连接， 用于将多个光线路终 端 1传输的光多带复用信号复合到单一光纤中。 多个光网络单元 3通过光纤 4与阵列波导光栅 62相连接， 阵列波导光栅 62的多个输出端分别与光网络 单元 3的光电接收器 31相连接， 使光网络单元 3通过阵列波导光栅 62接收 光线路终端发送的光多带复用信号。
每一个光线路终端 1的激光器发射产生的直流光的光波长不同， 而且两 个光线路终端 1产生的光波长的频差通常远大于同一个激光器通过 SBS原理 产生子光波之间的频差 A f , —般而言， A f 不超过 10 GHz , 而两个光线路终 端 1的激光器产生的光波长的频差可达 100GHz。 这样， 则可以利用阵列波导 光栅 61把不同波长的光信号合成一路进行传输， 再通过阵列波导光栅 62将 不同波长的光信号分开。
实施例三
本发明还可以应用于光分束器和阵列波导光栅共同存在的时分波分无源 光网络系统中。
图 4是本实施例提供的光网络系统的结构示意图， 如图 4所示， 本发明 的光网络系统包括： 多个光线路终端 1、 光分束器 2、 多个光网络单元 3、 阵 列波导光栅 61、 阵列波导光栅 62和用于连接的光纤 4。
本实施例中的结构与实施例二的相类似， 区别在于，在光网络单元侧中， 在阵列波导光栅 62之后， 还可以通过光分束器 2与各光网络单元 3相连接， 可以提高接入用户密度、 延长接入距离， 适合多局点融合的方式， 以适应时 分、 波分复用共存的无源光网络系统。
以上是对本发明所提供的光网络系统进行的详细描述， 下面对本发明提 供的光网络通信方法进行详细描述。
实施例四
图 5是本实施例提供的一种光网络信号处理方法流程图， 如图 5所示， 在光线路终端侧， 本发明的光网络信号处理方法包括：
S10 激光器产生的直流光在第一光纤中传输， 通过 SBS激发， 形成本 振光和反向传输的第一子光波。
其中， 所述本振光为所述直流光中光功率小于 SBS阈值的光信号， 所述 第一子光波为光功率大于 SBS阈值的光信号。 所述第一子光波与所述激光器 产生的直流光的频差为 Δ f。
具体地， SBS的原理： 当进入到光纤中的激光 λ。光功率达到一定值时， 由于 SBS , 会激发出子光波（斯托克斯 S tockes光波） λ ΐ 入 具有以下特点： 1 ) λ。与 反向； 2 ) 人 与 λ。存在一定的频差 Af , 该频差 Af 可以控制； 3 ) 入1与人。偏振态相同； 4 )如果人 再次进入光纤， 功率达到 SBS域值时， 会再 次激发下一级次的斯托克斯光 λ 2, λ 2与人 频差仍为 Af ; 5 ) SBS在任何光纤 中都能激发， 在非线性系数很高的高非线性光纤（HNF ) 中激发域值更低， 所 需光纤长度很短。
S1 02、 对所述第一子光波进行光信号放大处理， 并将所述放大处理后的 光信号在第二光纤中传输， 通过 SBS激发， 形成光载波和反向传输的第二子 光波， 所述光载波用于与输入的下行电信号进行调制后形成信号光。
其中， 所述第二子光波为所述放大处理后的光信号中光功率大于 SBS阈 值的光信号， 所述光载波为所述放大处理后的光信号中光功率小于 SBS阈值 的光信号。 所述第二子光波与所述第一子光波的频差为 A f。
S1 03、 所述本振光与所述信号光合波形成光多带复用信号， 并将光多带 复用信号输出给光网络单元。
可选的， 在将光多带复用信号输出给光网络单元之前， 还包括： 将多路 所述光多带复用信号复合成一路， 将复合后的光多带复用信号通过光纤传送 给光网络单元。 具体地， 可以通过阵列波导光栅将多路所述光多带复用信号 复合成一路后， 再通过主干光纤传输给光网络单元侧， 以到达每个光网络单 元。
图 6是本实施例提供的又一种光网络信号处理方法流程图，如图 6所示， 在光网络单元侧， 本发明的光网络信号处理方法包括：
S20 接收光线路终端发送的光多带复用信号， 所述光多带复用信号包 括本振光和多个信号光， 所述信号光分别与所述本振光进行相干混频， 得到 电多带复用信号。
光网络单元可以通过光分束器接收光线路终端发送的光多带复用信号， 也可以通过阵列波导光栅接收光线路终端发送的光多带复用信号。
可选的， 接收光线路终端发送的光多带复用信号， 包括：
接收多个光线路终端发送复合的光多带复用信号， 对所述复合的光多带 复用信号进行分离， 分别得到单个光多带复用信号。
S202、对所述电多带复用信号进行带通滤波，获取所需要频段的电信号， 并进行解调处理得到所述光线路终端接收到的下行信号。
本发明提供的光线路终端、 光网络单元、 光网络系统及信号处理方法， 利用光纤受激布里渊散射 SBS激发， 并经过逐级结构得到波长之间频率间隔 稳定的光载波， 利用光调制器进行调制加载下行电信号， 能使所有子带信号 均在光纤和射频器件传输性能最好的基带进行传输， 从而能够克服光纤色散 引起的高频衰减， 克服各种光电器件在高频处的频响不足、 滚降。 而且， 由 于产生的各光波波长之间频率间隔稳定， 不受激光器波长抖动影响， 能够产 生频率间隔很窄的子光波， 精度高， 各光波长偏振态一致， 保证在接收里完 全相干混频得到电多带复用信号。 同时， 在 PD接收时， 减小子带间的非线性 混频噪声。
专业人员应该还可以进一步意识到， 结合本文中所公开的实施例描述的 各示例的单元及算法步骤， 能够以电子硬件、 计算机软件或者二者的结合来 实现， 为了清楚地说明硬件和软件的可互换性， 在上述说明中已经按照功能 一般性地描述了各示例的组成及步骤。 这些功能究竟以硬件还是软件方式来 执行， 取决于技术方案的特定应用和设计约束条件。 专业技术人员可以对每 个特定的应用来使用不同方法来实现所描述的功能， 但是这种实现不应认为 超出本发明的范围。
结合本文中所公开的实施例描述的方法或算法的步骤可以用硬件、 处理 器执行的软件模块， 或者二者的结合来实施。 软件模块可以置于随机存储器 ( RAM ) 、 内存、 只读存储器（ROM ) 、 电可编程 R0M、 电可擦除可编程 R0M、 寄存器、 硬盘、 可移动磁盘、 CD-ROM , 或技术领域内所公知的任意其它形式 的存储介质中。
以上所述的具体实施方式， 对本发明的目的、 技术方案和有益效果进行 了进一步详细说明， 所应理解的是， 以上所述仅为本发明的具体实施方式而 已， 并不用于限定本发明的保护范围， 凡在本发明的精神和原则之内， 所做 的任何修改、 等同替换、 改进等， 均应包含在本发明的保护范围之内。

Claims

权 利 要 求 书
1、 一种光线路终端， 其特征在于， 所述光线路终端包括： 激光器、 合波 器、 光放大器、 光调制器、 第一光纤和第二光纤；
所述激光器， 用于产生直流光；
所述第一光纤， 与所述激光器和所述合波器相连接， 用于将所述激光器 产生的所述直流光通过受激布里渊散射 SBS 激发， 形成本振光和反向传输的 第一子光波， 并将所述本振光传输给所述合波器； 其中， 所述本振光为所述 直流光中光功率小于 SBS 阈值的光信号， 所述第一子光波为所述直流光中光 功率大于 SBS阈值的光信号；
所述光放大器， 与所述第一光纤和所述第二光纤相连接， 用于对所述第 一子光波进行光信号放大处理， 并将所述放大处理后的光信号传输给所述第 二光纤；
所述第二光纤， 与所述光放大器和所述光调制器相连接， 用于将所述光 放大器放大处理后的光信号通过 SBS 激发， 形成光载波和反向传输的第二子 光波， 并将所述光载波传输给所述光调制器； 其中， 所述第二子光波为所述 放大处理后的光信号中光功率大于 SBS 阈值的光信号， 所述光载波为所述放 大处理后的光信号中光功率小于 SBS阈值的光信号；
所述光调制器， 与所述第二光纤和所述合波器相连接， 用于将所述光载 波与输入的下行电信号进行调制后形成信号光， 并传输给所述合波器；
所述合波器， 与所述第一光纤和所述光调制器相连接， 用于将所述第一 光纤形成的本振光与所述光调制器形成的信号光合波形成光多带复用信号并 输出。
2、 根据权利要求 1所述的光线路终端， 其特征在于， 所述第一光纤通过 第一光环形器与所述激光器相连接， 所述第一光环形器的第一端与所述激光 器的输出端相连接， 所述第一光环形器的第二端与所述第一光纤相连接， 将 所述激光器产生的所述直流光传输给所述第一光纤， 所述第一光环形器的第 三端与所述光放大器的输入端相连接， 将所述第一光纤形成的所述第一子光 波传输给所述光放大器。
3、 根据权利要求 1所述的光线路终端， 其特征在于， 所述光放大器通过 第二光环形器与所述第二光纤相连接， 所述第二光环形器的第一端与所述光 放大器的输出端相连接， 所述第二光环形器的第二端与所述第二光纤相连接， 将所述光放大器放大处理后的光信号传输给所述第二光纤， 所述第二光环形 器的第三端与下一个所述光放大器相连接， 将所述第二光纤中形成的所述第 二子光波传输给下一个所述光放大器。
4、 根据权利要求 1所述的光线路终端， 其特征在于， 所述第一光纤中形 成的所述第一子光波与所述激光器产生的直流光的频差为 A f , 所述第二光纤 中形成的所述第二子光波与所述第一子光波的频差为 A f。
5、 一种光网络单元， 其特征在于， 所述光网络单元包括： 光电接收器、 带通滤波器和解调器；
所述光电接收器， 用于接收光线路终端发送的光多带复用信号， 所述光 多带复用信号包括本振光和多个信号光， 所述信号光分别与所述本振光进行 相干混频， 得到电多带复用信号；
所述带通滤波器， 用于对所述光电接收器得到的所述电多带复用信号进 行带通滤波， 获取所需要频段的电信号， 并传输至所述解调器进行解调。
6、 一种光网络系统， 其特征在于， 所述光网络包括： 如权利要求 1 ~ 4 任一权项所述的光线路终端、 如权利要求 5所述的光网络单元和光分配网络； 所述光线路终端通过所述光分配网络与所述光网络单元相连接。
7、 一种光网络信号处理方法， 其特征在于， 所述方法包括：
激光器产生的直流光在第一光纤中传输， 通过受激布里渊散射 SBS激发， 形成本振光和反向传输的第一子光波； 其中， 所述本振光为所述直流光中光 功率小于 SBS阈值的光信号， 所述第一子光波为光功率大于 SBS阈值的光信 号； 对所述第一子光波进行光信号放大处理 , 并将所述放大处理后的光信号 在第二光纤中传输， 通过 SBS 激发， 形成光载波和反向传输的第二子光波； 其中， 所述第二子光波为所述放大处理后的光信号中光功率大于 SBS 阈值的 光信号， 所述光载波为所述放大处理后的光信号中光功率小于 SBS 阈值的光 信号， 所述光载波用于与输入的下行电信号进行调制后形成信号光；
所述本振光与所述信号光合波形成光多带复用信号， 并将光多带复用信 号输出给光网络单元。
8、 根据权利要求 7所述的方法， 其特征在于， 所述第一子光波与所述激 光器产生的直流光的频差为 A f , 所述第二子光波与所述第一子光波的频差为 ΐ α
9、 根据权利要求 7所述的方法， 其特征在于， 所述将光多带复用信号输 出给光网络单元之前， 还包括： 将多路所述光多带复用信号复合成一路， 将 复合后的光多带复用信号通过光纤传送给光网络单元。
10、 一种光网络信号处理方法， 其特征在于， 所述方法包括：
接收光线路终端发送的光多带复用信号， 所述光多带复用信号包括本振 光和多个信号光， 所述信号光分别与所述本振光进行相干混频， 得到电多带 复用信号；
对所述电多带复用信号进行带通滤波， 获取所需要频段的电信号， 并进 行解调处理得到所述光线路终端接收到的下行信号。
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