WO2009076888A1 - 光传输系统、装置和方法 - Google Patents

光传输系统、装置和方法 Download PDF

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Publication number
WO2009076888A1
WO2009076888A1 PCT/CN2008/073403 CN2008073403W WO2009076888A1 WO 2009076888 A1 WO2009076888 A1 WO 2009076888A1 CN 2008073403 W CN2008073403 W CN 2008073403W WO 2009076888 A1 WO2009076888 A1 WO 2009076888A1
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WIPO (PCT)
Prior art keywords
signal
optical
multiplexed
transmitted
module
Prior art date
Application number
PCT/CN2008/073403
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English (en)
French (fr)
Inventor
Yanfu Yang
Xiaogeng Xu
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to EP08861711A priority Critical patent/EP2157711A4/en
Publication of WO2009076888A1 publication Critical patent/WO2009076888A1/zh
Priority to US12/717,437 priority patent/US20100239264A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/08—Time-division multiplex systems
    • 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
    • H04B10/503—Laser transmitters
    • H04B10/505—Laser transmitters using external modulation
    • 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
    • H04B10/516—Details of coding or modulation
    • H04B10/5162—Return-to-zero modulation schemes
    • 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
    • H04B10/516—Details of coding or modulation
    • H04B10/548—Phase or frequency modulation
    • H04B10/556—Digital modulation, e.g. differential phase shift keying [DPSK] or frequency shift keying [FSK]
    • H04B10/5561—Digital phase modulation
    • 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
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/67—Optical arrangements in the receiver
    • H04B10/676—Optical arrangements in the receiver for all-optical demodulation of the input optical signal
    • H04B10/677—Optical arrangements in the receiver for all-optical demodulation of the input optical signal for differentially modulated signal, e.g. DPSK signals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2220/00—Application
    • F05B2220/60—Application making use of surplus or waste energy
    • F05B2220/602—Application making use of surplus or waste energy with energy recovery turbines

Definitions

  • the present invention relates to the field of optical communications, and in particular, to an optical transmission system, a light emitting device, a light receiving device, a method of light emitting, and a method of light receiving.
  • the current rate of optical networks is mainly 10 Gb/s, so speed upgrades are required for optical networks, and the next-generation optical network rates are 40 Gb/s and higher.
  • the rate of Ethernet is upgraded at a rate of 10 times, such as 100GE (Gigabit Ethernet, Gigabit Ethernet).
  • 100GE Gigabit Ethernet, Gigabit Ethernet
  • the optical transmission technology of 100Gb/s has become a hot issue today.
  • the optical modulation pattern is the key to the whole system.
  • the choice of modulation pattern is directly related to the transmission performance, spectral efficiency, nonlinear tolerance, dispersion tolerance and other characteristics of the optical transmission system.
  • RZ Non-Return Zero
  • CSRZ Carrier-Supressed Return Zero
  • ODB Optical Doubinary
  • DRZ Return Zero Doubinary
  • P DQPSK Differential Quadrature Phase Shifter Keying
  • optical modulation patterns such as DQPSK, VSB (Vestigal Side Band), RZ, and ODB.
  • optical modulation patterns such as DPSK (Differential Phase Shifter Keying), DQPSK spectral smoothing, nonlinear tolerance and dispersion tolerance, it has become an alternative to 40Gb/s and 100Gb/s. one.
  • the adjacent pulse phases are compared to obtain the correct information for transmitting data.
  • the 100Gb/s RZ-DQPSK system will be described as an example.
  • the data to be transmitted is precoded at the transmitting end of the RZ-DQPSK system, and is divided into two paths, one for the ⁇ signal input to one arm of the dual parallel modulator. The other is the signal input to the other arm of the double parallel arm modulator.
  • the optical signal from the LD laser
  • the DQPSK optical signal passes through an RZ
  • the RZ-DQPSK optical pulse signal is obtained after the pulse generating unit, and then input into the transmission fiber.
  • the phases of the first optical pulse signal to the sixth optical pulse signal are respectively: 5 ⁇ /4, ⁇ /4, 7 ⁇ /4, 3 ⁇ /4, 3 ⁇ /4 and ⁇ /4.
  • the precoding part is a key part of the DQPSK optical transmission system, including multiplexing and precoding.
  • an 8-way 12.5 Gb/s signal is multiplexed into a 100 Gb/s signal as an example.
  • 4 channels of 12.5Gb/s signals ⁇ , 1 2 , 1 3 and 1 4 are multiplexed into 50Gb/s signal U by EMUX (Electronical Multiplexing), 4 channels of 12.5Gb/s signals
  • Q 2 , Q 3 and Q 4 are multiplexed into a 50 Gb/s signal V via EMUX.
  • Signals U and V represent in-phase and quadrature-specific components, respectively.
  • the 50Gb/s U and V signals are then precoded to obtain the final encoded 50Gb/s signal and the Q m signal is input to the dual parallel modulator.
  • the optical signal modulated by the dual parallel modulator is then converted into an optical pulse signal, and then transmitted through the optical fiber to the receiving end.
  • the RZ-DQPSK optical signal from the optical fiber is converted into intensity information by MZI (Mach-Zender Interferometer), and the converted optical signal is received by the balanced receiver, and then converted. For electrical signals.
  • the MZI delays one channel in the transmission signal by one symbol period, and the symbol period refers to the signal of the multiplexed device of the transmitting end device.
  • the symbol period is 20 ps in the 100 Gb/ s RZ-DQPSK system, and the other is added with a certain phase change.
  • the second optical signal in MZI1 is added with a change of ⁇ /4 phase
  • the second optical signal in ⁇ 2 is added with a phase change of -4.
  • MZI1 performs a delay of 1 symbol period on the first optical signal, and adds /4 optical signal to the second optical signal, and receives a current signal after receiving by the balanced receiver 1, thereby obtaining the transmission. Data information.
  • the transmission data A is precoded at the transmitting end to obtain precoded data B.
  • the transmission data may be multiplexed first and then precoded (not shown in the multiplexer diagram).
  • the precoding part of the DPSK system is mainly composed of an exclusive OR gate XOR and an lbit delay.
  • the two input data of the XOR comes from the lbit delay of the transmitted data A and the obtained precoded data B.
  • the precoded data B is modulated by MZM (Mach-Zender modulator), input into the optical fiber, and transmitted to the receiving end via the optical fiber.
  • MZM Machine-Zender modulator
  • the signal transmitted from the receiving end to the optical fiber is demodulated by MZI. Since the adjacent pulse phase change in the DPSK system carries the data information, the MZI delays the time of 1 baud for one signal in the transmitted signal. In the 40Gb/s DPSK system, it is 25ps. After the MZI converted optical signal is received by the balanced receiver, it is converted into an electrical signal to obtain the information of the transmitted data.
  • the precoding portion of the RZ-DQPSK system or DPSK system requires high-speed devices to achieve a delay of 1 symbol period to complete precoding. For example, in a 100Gb/s system, a 50Gb/s electrical logic device is required for the precoding portion. This requires high hardware, is technically demanding, and is implemented using high-speed precoding devices. Low-speed precoding devices cannot be used, which is also a waste of cost. Summary of the invention
  • embodiments of the present invention provide an optical transmission system, a light emitting device, a light receiving device, a light emitting method, and a light receiving method.
  • the technical solution is as follows:
  • an embodiment of the present invention provides an optical transmission system, where the system includes:
  • a transmitting end device configured to perform precoding on the signal to be transmitted, and then multiplex the data obtained by the precoding, modulate the multiplexed signal, and output the modulated optical signal,
  • a non-adjacent optical pulse signal in the modulated optical signal carries information of the signal to be transmitted;
  • a receiving end device configured to receive an optical signal output by the transmitting end device, demodulate the optical signal according to a preset delay, and convert the demodulated optical signal into an electrical signal, according to the electrical
  • the signal obtains information of the signal to be transmitted;
  • the preset delay is a product of a number of branches multiplexed by the transmitting device and a symbol period of a signal multiplexed by the transmitting device.
  • an embodiment of the present invention further provides a light emitting device, where the device includes:
  • a precoding module for precoding the signal to be transmitted
  • a multiplexing module configured to multiplex data obtained by the precoding module
  • a modulation module configured to modulate a signal multiplexed by the multiplexing module, and output the modulated optical signal, where the non-adjacent optical pulse signal of the modulated optical signal carries the signal to be transmitted Information.
  • an embodiment of the present invention further provides a light receiving device, where the device includes:
  • a demodulation module configured to demodulate an optical signal of a transmission signal received by the device according to a preset delay, where the preset delay is a number of branches multiplexed by a transmitting device that transmits the transmission signal a product of a symbol period of a signal multiplexed with the transmitting device;
  • a conversion module configured to convert the demodulated optical signal into an electrical signal, and obtain information about the transmitted signal according to the electrical signal.
  • an embodiment of the present invention provides a method for light emission, where the method includes:
  • the multiplexed signal is modulated to output the modulated optical signal, and the non-adjacent optical pulse signal of the modulated optical signal carries information of the signal to be transmitted.
  • an embodiment of the present invention further provides a method for optical reception, where the method includes:
  • the preset delay is a number of branches multiplexed by a transmitting device that sends the optical signal, and a symbol of a signal multiplexed by the transmitting device Product of the period;
  • the transmitting end is pre-coded and then multiplexed, and the result of the product of the symbol period time and the number of branches multiplexed by the transmitting end is demodulated as a delay time, and is used in a high-speed optical transmission system.
  • Some low-speed devices implement high-speed precoding functions, and correspondingly use extended delay time in demodulation. This solution reduces the implementation difficulty and cost of the system.
  • FIG. 1 is a schematic diagram of a transmitting end of a RZ-DQPSK system in the prior art
  • FIG. 2 is a schematic diagram of an RZ-DQPSK optical signal at the transmitting end of the RZ-DQPSK system in the prior art
  • FIG. 3 is a schematic diagram of a precoding portion of a transmitting end of an RZ-DQPSK system in the prior art
  • FIG. 4 is a schematic diagram of a receiving end of a RZ-DQPSK system in the prior art
  • FIG. 5 is a schematic diagram of optical signals and electrical signals at the receiving end of the RZ-DQPSK system in the prior art
  • FIG. 6 is a schematic diagram of a transmitting end of a DPSK system in the prior art
  • FIG. 7 is a schematic diagram of a receiving end of a DPSK system in the prior art
  • Figure 8 is a structural diagram of an optical transmission system according to Embodiment 1 of the present invention.
  • FIG. 9 is a schematic diagram of precoding of a transmitting end device in an optical transmission system according to Embodiment 1 of the present invention.
  • FIG. 10 is a schematic diagram of a non-adjacent RZ-DQPSK optical pulse signal obtained by a transmitting end device in an optical transmission system according to Embodiment 1 of the present invention
  • FIG. 11 is a schematic diagram of a receiving end in an optical transmission system according to Embodiment 1 of the present invention
  • Figure 12 is a schematic diagram of the MZI1 demodulation and balance receiver 1 of Figure 11 converted into an electrical signal
  • FIG. 13 is a schematic diagram of another transmitting end in the optical transmission system according to Embodiment 1 of the present invention.
  • FIG. 14 is a schematic diagram of another receiving end in an optical transmission system according to Embodiment 1 of the present invention.
  • Figure 15 is a structural view of a light-emitting device according to Embodiment 2 of the present invention.
  • Figure 16 is a structural diagram of a light receiving device according to Embodiment 3 of the present invention.
  • FIG. 17 is a flow chart of a method for light emission according to Embodiment 4 of the present invention.
  • Figure 18 is a flow chart showing a method of light reception according to Embodiment 5 of the present invention. detailed description
  • the optical transmission system in the embodiments of the present invention may employ a plurality of optical modulation patterns including, but not limited to, RZ-DQPSK, RZ-DQPSK CS-RZ-DQPSK RZ-DPSK RZ-DPSK, CS-RZ-DPSK, and the like.
  • an embodiment of the present invention provides an optical transmission system, which specifically includes:
  • the transmitting end device 801 is configured to perform precoding on the signal to be transmitted, then multiplex the precoded data, modulate the multiplexed signal, and output the modulated optical signal, and the modulated optical signal is not
  • An adjacent optical pulse signal carries information of a signal to be transmitted; for example, a phase change between non-adjacent optical pulse signals in the modulated optical signal carries information of a signal to be transmitted;
  • the receiving end device 802 is configured to receive the optical signal output by the transmitting end device 801, demodulate the optical signal according to a preset delay, convert the demodulated optical signal into an electrical signal, and obtain a to-be-transmitted according to the electrical signal.
  • the information of the signal wherein, the preset delay is the product of the number of branches multiplexed by the transmitting device and the symbol cycle time of the signal multiplexed by the transmitting device.
  • the foregoing transmitting device 801 specifically includes:
  • a precoding module configured to pre-code each tributary signal to be transmitted to obtain multiplexed data
  • a multiplexing module configured to multiplex the multiplexed data obtained by the precoding module
  • a modulation module configured to modulate a signal multiplexed by the multiplexing module, and output the modulated optical signal, wherein the non-adjacent optical pulse signal in the modulated optical signal carries information of the signal to be transmitted.
  • the process of precoding and multiplexing by the transmitting end device 801 in this embodiment may specifically include: precoding each of the multiple signals to be transmitted according to a delay time of the symbol period thereof to obtain multi-channel encoded data; The resulting multiplexed encoded data is then multiplexed.
  • precoding each of the multiple signals to be transmitted according to a delay time of the symbol period thereof to obtain multi-channel encoded data The resulting multiplexed encoded data is then multiplexed.
  • 100Gb/ s optical transmission using the RZ-DQPSK optical modulation pattern The system is described as an example.
  • There are 8 12.5 Gb/s tributary signals to be transmitted at the transmitting end namely U 2 , U 3 , U 4 , 1 ⁇ 4, V 2 , V 3 and V 4 .
  • the transmitting device separately performs DQPSK precoding on the eight transmission signals to obtain eight channels of 12.5 Gb/s encoded data, namely ⁇ , I 2 ', I 3 ', I 4 , Q 2 ', Q 3 ' and Q 4 .
  • precoding rules There are a variety of precoding rules, which can be used but are not limited to the following rules:
  • EMUX multiplexes the obtained ⁇ , ⁇ 2 ', ⁇ 3 ', and ⁇ 4 , and obtains a signal of 50 Gb/s after multiplexing, and Q, Q 2 ', Q obtained by another multiplexer EMUX. 3 ' is multiplexed with Q 4 and multiplexed to obtain a signal Q' at a rate of 50 Gb/s.
  • the multiplexed signals ⁇ and Q' are then input to the modulator for modulation.
  • the precoding module of the transmitting end device 801 in this embodiment can implement the precoding function by using an existing common low speed device. For example, in a 100 Gb/ s optical transmission system using an RZ-DQPSK optical modulation pattern, there are eight 12.5 Gb/s tributary signals to be transmitted at the transmitting end. Referring to FIG. 3, multiplexing is performed in the prior art. Obtaining two 50Gb/s signals and then performing precoding, the precoding portion needs high speed device to implement; Referring to FIG. 9, in this embodiment, the 12.5Gb/s tributary signal is precoded to obtain the rate. Still encoding data of 12.5 Gb/s, and then multiplexing the encoded data of 12.5 Gb/s, the precoding portion can be implemented by using an existing ordinary low-speed device.
  • the transmitting device 801 in this embodiment can employ a variety of modulators, such as a dual parallel modulator, an electrical modulator, or an MZM.
  • the non-adjacent RZ-DQPSK optical signal can be obtained after modulation by the dual parallel modulator; the transmitting end device 801 in this embodiment can specifically convert the modulated signal into light by using the RZ pulse generating unit.
  • Pulse signal for example, referring to FIG. 10, the RZ pulse generating unit converts the signal obtained by the modulation of the modulator in the transmitting device 801 into six optical pulse signals with phases of 5 ⁇ /4, JI /4, 7 ⁇ / 4, 3 ⁇ /4, 3 ⁇ /4 ⁇ ⁇ /4.
  • the phase change between the two optical pulse signals whose sequence numbers differ by 4 in the obtained optical pulse signal carries information of the transmission signal, such as the first optical pulse signal.
  • the phase change of the fifth optical pulse signal carries the information of the first bit in the transmission signal
  • the phase change of the second optical pulse signal and the sixth optical pulse signal carries the information of the second bit in the transmission signal and the like.
  • the receiving end device 802 in this embodiment has different delays in demodulation, and the rest are the same.
  • the delay time of the demodulation is the product of the number of branches multiplexed by the transmitting end device 801 and the symbol period time of the signal multiplexed by the transmitting end device 801, which is longer than the delay time in the prior art. Understand the delay of the regulator Wai.
  • the number of branches multiplexed by the multiplexer in the transmitting device 801 is 4, and the delay of the receiving device 802 is demodulated.
  • the time is 4 times the symbol period time, which is 80ps.
  • MZI1 and MZI2 both delay the signal transmitted by the optical fiber by 80ps, and demodulate the signals of /4 and - ⁇ /4 respectively, and the signals obtained after demodulation are output to the balanced receiver 1 and the balanced receiver 2 respectively. , thereby obtaining an electrical signal, according to the level of the electrical signal can be obtained information of the transmitted signal, such as the corresponding level "low high, low, high” resulting in a transmission signal of "01101" and so on.
  • MZI1 is delayed by 80ps, and the additional signal is demodulated.
  • the demodulated output is converted by the balanced receiver 1 to obtain an electrical signal. If the two high levels are high, the corresponding transmission signal is "11" or "00".
  • the optical transmission system in this embodiment is described by taking the 100 Gb/s optical transmission system using the RZ-DQPSK optical modulation pattern as an example.
  • the optical transmission system in this embodiment may also adopt other optical modulation patterns, such as DPSK.
  • Optical modulation pattern The following is an example of a 40 Gb/s optical transmission system using a DPSK optical modulation pattern.
  • the transmitting end has two channels of transmission data A1 and A2, which are respectively input to the precoding section 1 and the precoding section 2 for precoding, and the precoding uses an XOR XOR gate and a lbit delayer to obtain pre-preparations respectively.
  • the receiver uses MZI to demodulate the signal transmitted by the fiber, and then converts it into an electrical signal by the balanced receiver. Since the number of branches multiplexed by the multiplexer EMUX of the transmitting device is 2, the delay time of the MZI is twice the symbol cycle time of the signal multiplexed by the transmitting device, in the 40 Gb/s optical transmission system. It is 50ps.
  • the transmitting end device 801 pre-codes and then multiplexes, and the receiving end demodulates the result of the product of the symbol period time of the signal multiplexed by the transmitting end and the number of branches multiplexed by the transmitting end as the delay time.
  • the existing low-speed device is used to implement the high-speed precoding function, and accordingly, the extended delay time is adopted in demodulation, which reduces the implementation difficulty and cost of the system.
  • the number of branches multiplexed at the transmitting end determines the delay time of demodulation at the receiving end and the low speed rate after the branch is reduced.
  • the branch rate is inversely proportional to the number of multiplexed branches, and the delay time of demodulation is proportional to the number of multiplexed branches.
  • an embodiment of the present invention further provides a light emitting device, which specifically includes:
  • a precoding module 1501 configured to perform precoding on a signal to be transmitted
  • a multiplexing module 1502 configured to multiplex data obtained by the precoding module 1501;
  • the modulation module 1503 is configured to modulate the multiplexed signal of the multiplexing module 1502, and output the modulated optical signal, where the non-adjacent optical pulse signal of the modulated optical signal carries information of the signal to be transmitted; for example, modulation The phase change between the non-adjacent optical pulse signals in the latter optical signal carries information of the signal to be transmitted.
  • the precoding module 1501 specifically includes:
  • a precoding unit for precoding each of the branch signals to be transmitted to obtain multiplexed data; for example, if the signal to be transmitted has 10 tributary signals, each of the tributary signals is separately pre-prepared Encoding, you can get 10 channels of encoded data.
  • the multiplexing module 1502 may be specifically an EMUX or the like, and the number of multiplexing branches specifically used by the multiplexing module 1502 may be determined according to actual conditions.
  • the modulation module 1503 may be specifically a dual parallel modulator, an electrical modulator, or an MZM or the like.
  • the precoding module 1501 of the transmitting device in this embodiment can implement the precoding function by using an existing conventional low speed device.
  • the specific process of precoding, multiplexing, modulating, and converting into an optical pulse signal is the same as that described in Embodiment 1, and will not be described herein.
  • the number of branches when the multiplexing module 1502 is multiplexed that is, the phase change in which the sequence numbers of the optical pulse signals obtained by the light emitting device differ by the number of the two optical pulse signals carries the information of the transmission signal.
  • the multiplexing module 1502 employs a 4-way multiplexer
  • the phase change between the two optical pulse signals whose sequence numbers differ by 4 in the obtained optical pulse signal carries the information of the transmission signal.
  • the phases of the two optical pulse signals with a fixed number of phases are compared, and the fixed number of phase differences is equal to the transmitting end.
  • the number of branches multiplexed in the device.
  • the optical transmitting device is pre-coded and then multiplexed, so that the existing low-speed device can be used in the high-speed optical transmission system to implement the high-speed precoding function, thereby reducing the implementation difficulty of the system and reducing the system. cost.
  • an embodiment of the present invention further provides a light receiving device, which specifically includes:
  • the demodulation module 1601 is configured to demodulate the optical signal of the transmission signal received by the optical receiving device according to a preset delay, where the preset delay is the number of branches multiplexed by the transmitting device that transmits the transmission signal, and the a product of symbol period times of signals multiplexed by the transmitting device;
  • the conversion module 1602 is configured to convert the optical signal demodulated by the demodulation module 1601 into an electrical signal, and obtain information of the transmission signal according to the electrical signal.
  • the demodulation module 1601 may be specifically an MZI, and the conversion module 1602 may be specifically a receiver, including a balanced receiver, a normal PIN tube, and the like.
  • the receiving end device in this embodiment has different delay time during demodulation, and the rest are the same.
  • the delay time during demodulation is the number of branches multiplexed by the transmitting device and the signal multiplexed by the transmitting device
  • the product of the symbol period time of the number is longer than the delay time in the prior art, which expands the delay range of the demodulator. For example, in the 100 Gb/s optical transmission system using the RZ-DQPSK optical modulation pattern, if the number of branches multiplexed by the multiplexer in the transmitting device is 4, the delay time of the demodulation of the receiving device is 4 times.
  • the symbol period time is 80ps.
  • the result of multiplying the symbol period time of the signal multiplexed by the transmitting end device and the number of branches multiplexed by the transmitting end by the optical receiving device is used as the delay time for demodulation, and an extended delay is adopted in demodulation. Time, which reduces the difficulty of the system.
  • an embodiment of the present invention provides a method for light emission, which specifically includes:
  • Step 1701 Precoding the signal to be transmitted; wherein, the precoding may adopt an existing precoding rule; the precoding process may specifically precode each tributary signal of the signal to be transmitted to obtain multiplexed data;
  • Step 1702 multiplexing the pre-coded data, specifically, multiplexing the multi-coded data obtained by pre-coding, for example, using EMUX to multiplex four channels of 12.5 Gb/s encoded data to obtain one channel of 50 Gb. /s signal;
  • step 1703 modulating the multiplexed signal; wherein, the modulation can be implemented by using a plurality of modulators, such as a dual parallel modulator, an electric modulator, or an MZM;
  • Step 1704 The modulated optical signal is output to the optical fiber and transmitted to the receiving end via the optical fiber. Further, the modulated optical signal may be converted into an RZ optical pulse signal by using an RZ pulse generating unit or the like, wherein the modulated light is The non-adjacent optical pulse signal in the signal carries information of the signal to be transmitted, such as a phase change between non-adjacent optical pulse signals in the modulated optical signal carrying information of the signal to be transmitted.
  • precoding in this embodiment can be implemented by using an existing conventional low speed device.
  • precoding and then multiplexing at the transmitting end it is ensured that the high speed precoding function is implemented by using the existing low speed device in the high speed optical transmission system, thereby reducing the implementation difficulty of the system and reducing the system. cost.
  • an embodiment of the present invention further provides a method for receiving light, which specifically includes:
  • Step 1801 Receive an optical signal of a transmission signal, where the optical signal carries information of a signal to be transmitted at a transmitting end.
  • Step 1802 Demodulate the received optical signal according to a preset delay, such as using MZI for demodulation, and the preset delay is the number of branches multiplexed by the transmitting device transmitting the transmission signal and the transmission.
  • the product of the symbol cycle time of the signal multiplexed by the end device for example, the number of branches multiplexed in the 100 Gb/ s system is 2, and the symbol cycle time of the multiplexed signal is 20 ps, and the receiver demodulates
  • the delay time is 2 times the symbol period time, that is, 40p S;
  • Step 1803 Convert the demodulated optical signal into an electrical signal, such as converting with a balanced receiver, and obtaining information of the signal to be transmitted according to the electrical signal.
  • demodulation is performed according to the time of the product of the symbol period time of the signal multiplexed by the transmitting end and the number of branches multiplexed by the transmitting end, and an extended delay is adopted in demodulation. Time, which reduces the difficulty of the system.
  • Embodiments of the invention may be implemented in software, and the corresponding software may be stored in a readable storage medium, such as a hard disk of a light emitting device or a hard disk of a light receiving device.

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  • Engineering & Computer Science (AREA)
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Description

光传输系统、 装置和方法 本申请要求于 2007年 12月 14日提交中国专利局、 申请号为 200710160976.5、发明名称 为 "光传输系统、 装置和方法" 的中国专利申请的优先权， 其全部内容通过引用结合在本申 请中。
说
技术领域
本发明涉及光通信领域， 特别涉及一种光传输系统、 光发射装置、 光接收装置、 光发射 的方法和光接收的方法。
书
背景技术
随着网络中视频业务的增加， 对整个网络的容量提出了更高的要求。 现在的光网络的速 率主要是 10Gb/s速率， 因此需要对光网络进行速率升级， 下一代的光网络速率为 40Gb/s及 更高的速率。 以太网的速率以 10倍的速率进行升级， 如 100GE (Gigabit Ethernet, 吉比特以 太网）， 100Gb/s的光传输技术已经成为当今的一个热点问题。
在光传输系统中， 光调制码型是整个系统的关键， 调制码型的选择直接和光传输系统的 传输性能、 光谱效率、 非线性容忍度、 色散容忍度等特性直接相关。 在 lOGb/s光传输系统中 主要以 RZ (Non-Return Zero, 非归零） 为主要调制码型。 40Gb/s光传输系统存在着多种光 调制码型， 如 RZ、 RZ (Return Zero, 归零）、 CSRZ (Carrier-Supressed Return Zero, 载 波抑制归零）、 ODB (Optical Doubinary, 光双二进制）、 DRZ (Return Zero Doubinary, 归零 光双二进制） 禾 P DQPSK (Differential Quadrature Phase Shifter Keying, 差分正交相移键控码） 等。 100Gb/s光传输系统中存在 DQPSK、 VSB (Vestigal Side Band, 残留边带调制）、 RZ、 ODB等多种光调制码型。 由于光调制码型如 DPSK (Differential Phase Shifter Keying, 差分相 移键控码）、 DQPSK 的光谱平滑、 非线性容忍度及色散容忍度大， 因此已经成为 40Gb/s及 100Gb/s的备选方案之一。
现有技术的 DPSK和 DQPSK系统中是对相邻的脉冲相位进行比较从而得到传输数据的 正确信息。 首先以 100Gb/s RZ-DQPSK系统为例进行说明。 参见图 1， 在 RZ-DQPSK系统的 发射端先对待传输的数据进行预编码，分成两路，一路为 Ιιη信号输入到双平行调制器的一臂， 另一路为 „信号输入到双平行臂调制器的另一臂。 从 LD (激光器） 发出的光信号经过双平 行调制器调制后得到携带传输数据信号的 DQPSK光调制信号。 DQPSK光信号经过一个 RZ 脉冲产生单元后得到 RZ-DQPSK光脉冲信号， 然后输入到传输光纤中。 参见图 2， 为 6个光 脉冲信号，第一个光脉冲信号至第六个光脉冲信号的相位分别为： 5 π /4、 π /4、 7 π /4、 3 π /4、 3 π /4禾 Ρ π /4。 通过比较相邻两个光脉冲信号的相位差， 可以得出传输数据的信息。 如第 4个 光脉冲信号与第 5个光脉冲信号相比， 相位未发生变化， 第 5个光脉冲信号和第 6个光脉冲 信号相比， 相位发生变化， 相差 /2， 相应地， 可以得到传输数据中对应的两位数据信息。
其中预编码部分是 DQPSK光传输系统的关键部分， 包括复用和预编码。 参见图 3， 以 8 路 12.5Gb/s信号复用成 100Gb/s信号为例进行说明。 4路 12.5Gb/s信号 ^、 12、 13和 14经过 EMUX (Electronical Multiplexing, 电复用器）复用成 50Gb/s信号 U， 4路 12.5Gb/s信号
Q2、 Q3和 Q4经过 EMUX复用成 50Gb/s信号 V。 信号 U和 V分别表示同相和正交相比特分 量。 然后对 50Gb/s的 U和 V路信号进行预编码得到最终编码后的 50Gb/s信号 ^和 Qm信号 输入到双平行调制器中。 其中 50Gb/s的信号 U和 V的预编码规则为： = + (Q^㊉ -、
a = ( ― + ® -, wk ® ) 公式中的下标表示比特序列的时间位置， ®表示异或。 —表示取反。 双平行调制器调制 后的光信号再变成光脉冲信号， 然后经过光纤传输到达接收端。 参见图 4， 来自光纤的 RZ-DQPSK光信号经过 MZI (Mach-Zender Interferometer, 马赫-泽德干涉仪） 将差分的相位 信息转换为强度信息， 转换后的光信号经过平衡接收机接收后， 转换为电信号。 由于 RZ-DQPSK系统中相邻的脉冲相位变化携带了数据的信息，因此 MZI对传输信号中的一路延 时一个码元周期的时间， 该码元周期是指发射端装置复用后的信号的码元周期， 在 100Gb/S RZ-DQPSK系统中为 20ps， 另一路附加一定的相位变化。 其中， MZI1 中的第二路光信号附 加 π/4相位的变化， ΜΖΙ2中的第二路光信号附加- /4的相位变化。 参见图 5， MZI1对第一 路光信号进行 1码元周期的延时， 对第二路光信号附加 /4光信号， 经过平衡接收机 1接收 后得到电流信号， 由此可以得出传输的数据信息。
下面以 40Gb/s DPSK系统为例进行说明。 参见图 6， 在发射端对传输数据 A进行预编码 得到预编码数据 B， 也可以先对传输数据进行复用，然后预编码（复用器图中未画出）。 DPSK 系统中的预编码部分主要由一个异或门 XOR和一个 lbit延时器构成， XOR的两路输入数据 来自传输数据 A和得到的预编码数据 B的 lbit延时。预编码数据 B经过 MZM (Mach-Zender modulator, 马赫-泽德调制器） 调制后输入到光纤中， 经光纤传输给接收端。 参见图 7， 在接 收端对光纤传输来的信号， 采用 MZI进行解调， 由于 DPSK系统中相邻的脉冲相位变化携带 了数据的信息， 因此 MZI对传输信号中的一路信号延时 1波特率的时间， 在 40Gb/s DPSK系 统中即为 25ps， MZI转换后的光信号经过平衡接收机接收后， 转换为电信号， 从而得到传输 数据的信息。
在实现本发明的过程中， 发明人发现上述现有技术至少具有以下缺点：
RZ-DQPSK系统或 DPSK系统中的预编码部分需要采用高速器件来达到 1个码元周期的 延时， 从而完成预编码。 如在 100Gb/s系统中， 需要预编码部分采用 50Gb/s的电逻辑器件。 这对硬件的要求很高， 技术实现比较苛刻， 而且采用高速预编码器件来实现， 不能采用低速 的预编码器件， 在成本上也是很大的浪费。 发明内容
为了降低光传输过程中对硬件的要求， 本发明实施例提供了一种光传输系统、 光发射装 置、 光接收装置和光发射的方法、 光接收的方法。 所述技术方案如下：
一方面， 本发明实施例提供了一种光传输系统， 所述系统包括：
发射端装置， 用于对待传输信号先进行预编码， 然后对所述预编码得到的数据进行复用， 对所述复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非相邻 的光脉冲信号携带所述待传输信号的信息；
接收端装置， 用于接收所述发射端装置输出的光信号， 按预设的延时对所述光信号进行 解调， 将所述解调后的光信号转换为电信号， 根据所述电信号得到所述待传输信号的信息； 所述预设的延时为所述发射端装置复用的支路数目与所述发射端装置复用后的信号的码元周 期的乘积。
另一方面， 本发明实施例还提供了一种光发射装置， 所述装置包括：
预编码模块， 用于对待传输信号进行预编码；
复用模块， 用于对所述预编码模块得到的数据进行复用；
调制模块， 用于对所述复用模块复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非相邻的光脉冲信号携带所述待传输信号的信息。
另一方面， 本发明实施例还提供了一种光接收装置， 所述装置包括：
解调模块， 用于按预设的延时对所述装置收到的传输信号的光信号进行解调， 所述预设 的延时为发送所述传输信号的发射装置复用的支路数目与所述发射装置复用后的信号的码元 周期的乘积； 转换模块， 用于将所述解调模块解调后的光信号转换为电信号， 根据所述电信号得到所 述传输信号的信息。
一方面， 本发明实施例提供了一种光发射的方法， 所述方法包括：
对待传输信号进行预编码， 然后对所述预编码得到的数据进行复用；
对所述复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非 相邻的光脉冲信号携带所述待传输信号的信息。
另一方面， 本发明实施例还提供了一种光接收的方法， 所述方法包括：
接收传输信号的光信号；
按预设的延时对所述光信号进行解调， 所述预设的延时为发送所述光信号的发射装置复 用的支路数目与所述发射装置复用后的信号的码元周期的乘积；
将所述解调后的光信号转换为电信号， 根据所述电信号得到所述传输信号的信息。 本发明实施例提供的技术方案的有益效果是：
本发明实施例通过发射端先预编码后复用， 且接收端按码元周期时间与发射端复用的支 路数目乘积的结果作为延时时间进行解调， 在高速光传输系统中采用现有的低速器件来实现 高速的预编码功能， 相应地在解调时采用扩大的延时时间， 这种方案降低了系统的实现难度 和成本。 附图说明
图 1是现有技术中 RZ-DQPSK系统的发射端示意图；
图 2是现有技术中 RZ-DQPSK系统的发射端 RZ-DQPSK光信号示意图；
图 3是现有技术中 RZ-DQPSK系统的发射端预编码部分示意图；
图 4是现有技术中 RZ-DQPSK系统的接收端示意图；
图 5是现有技术中 RZ-DQPSK系统的接收端光信号和电信号的示意图；
图 6是现有技术中 DPSK系统的发射端示意图；
图 7是现有技术中 DPSK系统的接收端示意图；
图 8是本发明实施例 1提供的光传输系统的结构图；
图 9是本发明实施例 1的光传输系统中发射端装置预编码的示意图；
图 10是本发明实施例 1的光传输系统中发射端装置得到的非相邻 RZ-DQPSK光脉冲信 号示意图；
图 11是本发明实施例 1的光传输系统中接收端示意图； 图 12是图 11中的 MZI1解调及平衡接收机 1转换成电信号的示意图；
图 13是本发明实施例 1的光传输系统中另一种发射端示意图；
图 14是本发明实施例 1的光传输系统中另一种接收端示意图；
图 15是本发明实施例 2提供的光发射装置结构图；
图 16是本发明实施例 3提供的光接收装置结构图；
图 17是本发明实施例 4提供的光发射的方法流程图；
图 18是本发明实施例 5提供的光接收的方法流程图。 具体实施方式
为使本发明的目的、 技术方案和优点更加清楚， 下面将结合附图对本发明实施方式作进 一步地详细描述。
本发明实施例中的光传输系统可以采用多种光调制码型， 包括但不限于 RZ-DQPSK、 RZ-DQPSK CS-RZ-DQPSK RZ-DPSK RZ-DPSK和 CS-RZ-DPSK等等。
实施例 1
参见图 8， 本发明实施例提供了一种光传输系统， 具体包括：
发射端装置 801， 用于对待传输信号先进行预编码， 然后对预编码得到的数据进行复用， 对复用后的信号进行调制， 将调制后的光信号输出， 调制后的光信号中非相邻的光脉冲信号 携带待传输信号的信息； 例如， 调制后的光信号中非相邻的光脉冲信号之间的相位变化携带 待传输信号的信息；
接收端装置 802， 用于接收发射端装置 801输出的光信号， 按预设的延时对该光信号进 行解调， 将解调后的光信号转换为电信号， 根据该电信号得到待传输信号的信息； 其中， 预 设的延时为发射端装置复用的支路数目与发射端装置复用后的信号的码元周期时间的乘积。
进一步地， 上述发射端装置 801具体包括：
预编码模块， 用于对待传输信号的各支路信号分别进行预编码， 得到多路编码数据； 复用模块， 用于对预编码模块得到的多路编码数据进行复用；
调制模块， 用于对复用模块复用后的信号进行调制， 将调制后的光信号输出， 调制后的 光信号中非相邻的光脉冲信号携带待传输信号的信息。
本实施例中发射端装置 801进行预编码及复用的过程可以具体包括： 对待传输的多路信 号中的每一路信号按其码元周期的延时时间进行预编码， 得到多路编码数据； 然后对得到的 多路编码数据进行复用。 例如， 参见图 9， 以采用 RZ-DQPSK光调制码型的 100Gb/S光传输 系统为例进行说明， 在发射端有 8路 12.5Gb/s的待传输的支路信号， 分别为 、 U2、 U3、 U4、 ¼、 V2、 V3和 V4。 发射端装置分别对这 8路传输信号进行 DQPSK预编码， 得到 8路 12.5Gb/s的编码数据， 分别为 ΐ 、 I2'、 I3'、 I4、
Figure imgf000008_0001
Q2'、 Q3'和 Q4。 其中预编码的规则有多 种， 可以采用但不限于如下的规则：
= ( — ― ㊉ — ' ) + ® — wk ® ik.x )
公式中的下标表示比特序列的时间位置， ®表示异或。 —表示取反。 采用一个复用器
EMUX将得到的 ΐ 、 Ι2'、 Ι3'和 Ι4进行复用， 复用后得到速率为 50Gb/s的信号 Γ， 采用另一个 复用器 EMUX将得到的 Q 、 Q2'、 Q3'和 Q4进行复用， 复用后得到速率为 50Gb/s的信号 Q'。 然后将复用后的信号 Γ和 Q'输入到调制器中进行调制。
由于在复用前先进行预编码， 本实施例中发射端装置 801的预编码模块可以采用现有的 普通的低速器件来实现预编码功能。 例如， 在采用 RZ-DQPSK光调制码型的 100Gb/S光传输 系统中， 发射端有 8路 12.5Gb/s的待传输的支路信号， 参见图 3， 现有技术中先进行复用， 得到两个 50Gb/s的信号， 然后进行预编码， 则该预编码部分需要高速器件来实现； 参见图 9， 本实施例中， 先对 12.5Gb/s的支路信号进行预编码， 得到速率仍为 12.5Gb/s的编码数据， 然 后对 12.5Gb/s的编码数据进行复用，则该预编码部分可以采用现有的普通的低速器件来实现。
本实施例中的发射端装置 801可以采用多种调制器，如双平行调制器、电调制器或 MZM。 在图 9的例子中， 采用双平行调制器调制后可以得到非相邻的 RZ-DQPSK光信号； 本实施例 中的发射端装置 801可以具体采用 RZ脉冲产生单元将调制后的信号转换为光脉冲信号， 例 如， 参见图 10， RZ脉冲产生单元将发射端装置 801 中的调制器调制后得到的信号转换为 6 个光脉冲信号， 相位分别为 5 π /4、 JI /4、 7 π /4、 3 π /4、 3 π /4 Ρ π /4。 当预编码时采用 4支 路的复用器时， 得到的光脉冲信号中序列号相差为 4的两个光脉冲信号之间的相位变化携带 了传输信号的信息， 如第 1个光脉冲信号和第 5个光脉冲信号的相位变化携带了传输信号中 第 1位的信息， 第 2个光脉冲信号和第 6个光脉冲信号的相位变化携带了传输信号中第 2位 的信息等等。 与现有技术相比， 不再是对相邻的两个光脉冲信号的相位进行比较， 而是对相 差固定个数的两个光脉冲信号的相位进行比较， 相差的固定个数等于发射端装置中复用器的 支路复用数目。
本实施例中的接收端装置 802与现有技术中的接收端装置相比，解调时延时的时间不同， 其余均相同。 其中， 解调时延时的时间为发射端装置 801 复用的支路数目与发射端装置 801 复用后的信号的码元周期时间的乘积， 比现有技术中延时的时间长， 扩大了解调器的延时范 围。 例如， 参见图 11， 采用 RZ-DQPSK光调制码型的 100Gb/s光传输系统中， 发射端装置 801中复用器复用的支路数目为 4，则接收端装置 802解调时延时的时间为 4倍的码元周期时 间， 即 80ps。 其中， MZI1和 MZI2均对光纤传输来的信号延时 80ps， 并分别附加 /4和- π /4的信号进行解调， 解调后得到的信号分别输出给平衡接收机 1和平衡接收机 2， 从而得到 电信号， 根据该电信号的电平的高低可以得出传输信号的信息， 如对应电平 "低高高低高" 得到的传输信号为 "01101 "等等。 例如， 参见图 12， MZI1延时 80ps， 并附加 的信号进 行解调， 解调输出经过平衡接收机 1转换后得到电信号， 为两个高电平， 则对应的传输信号 为 " 11 "或 "00"。
上面以采用 RZ-DQPSK光调制码型的 100Gb/s光传输系统为例说明本实施例中的光传输 系统， 此外， 本实施例中的光传输系统还可以采用其他光调制码型， 如 DPSK光调制码型。 下面以采用 DPSK光调制码型的 40Gb/s光传输系统为例进行说明。 例如， 参见图 13， 发射 端有两路传输数据 A1和 A2， 分别输入到预编码部分 1和预编码部分 2进行预编码， 预编码 采用 XOR异或门和 lbit的延时器， 分别得到预编码数据 B1禾 P B2。 B1禾 P B2经过 EMXU复 用后加载在 MZM上， MZM进行调制得到非相邻 DPSK光信号， 然后输出给光纤。 参见图 14， 接收端采用 MZI对光纤传输来的信号进行解调， 然后由平衡接收机转换为电信号。 由于 发射端装置的复用器 EMUX复用的支路数目为 2，因此 MZI的延时时间为 2倍的发射端装置 复用后的信号的码元周期时间， 在 40Gb/s光传输系统中为 50ps。
本实施例通过发射端装置 801先预编码后复用， 且接收端按发射端复用后的信号的码元 周期时间与发射端复用的支路数目乘积的结果作为延时时间进行解调， 在高速光传输系统中 采用现有的低速器件来实现高速的预编码功能， 相应地在解调时采用扩大的延时时间， 这种 方案降低了系统的实现难度和成本。 发射端复用的支路数目决定了接收端解调的延时时间和 支路降低后的低速速率。 支路速率和复用支路数目成反比， 解调的延时时间和复用支路数目 成正比。
实施例 2
参见图 15， 本发明实施例还提供了一种光发射装置， 具体包括：
预编码模块 1501， 用于对待传输信号进行预编码；
复用模块 1502， 用于对预编码模块 1501得到的数据进行复用；
调制模块 1503， 用于对复用模块 1502复用后的信号进行调制， 将调制后的光信号输出， 调制后的光信号中非相邻的光脉冲信号携带待传输信号的信息； 例如， 调制后的光信号中非 相邻的光脉冲信号之间的相位变化携带待传输信号的信息。 其中， 预编码模块 1501具体包括：
预编码单元， 用于对待传输信号的各支路信号分别进行预编码， 得到多路编码数据； 例 如， 待传输信号有 10 个支路信号， 则对其中的每个支路信号都单独进行预编码， 可以得到 10路编码数据。
其中， 复用模块 1502可以具体为 EMUX等， 复用模块 1502具体采用的复用支路数目可 根据实际情况确定。
其中， 调制模块 1503可以具体为双平行调制器、 电调制器或 MZM等等。
本实施例中预编码模块进行预编码时采用的预编码规则有多种，可以采用的预编码规则。 由于在复用前先进行预编码，本实施例中发射端装置的预编码模块 1501可以采用现有的普通 的低速器件来实现预编码功能。 预编码、 复用、 调制以及转换为光脉冲信号的具体过程同实 施例 1中的描述， 此处不再赘述。
在本实施例中复用模块 1502复用时的支路数目，即光发射装置得到的光脉冲信号中序列 号相差为该数目的两个光脉冲信号的相位变化携带了传输信号的信息。例如，当复用模块 1502 采用 4支路的复用器时， 得到的光脉冲信号中序列号相差为 4的两个光脉冲信号之间的相位 变化携带了传输信号的信息。 与现有技术相比， 不再是对相邻的两个光脉冲信号的相位进行 比较， 而是对相差固定个数的两个光脉冲信号的相位进行比较， 相差的固定个数等于发射端 装置中复用的支路数目。
本实施例通过光发射装置先预编码然后进行复用， 可以保证在高速光传输系统中采用现 有的低速器件来实现高速的预编码功能， 从而降低了系统的实现难度， 且降低了系统的成本。
实施例 3
参见图 16， 本发明实施例还提供了一种光接收装置， 具体包括：
解调模块 1601， 用于按预设的延时对光接收装置收到的传输信号的光信号进行解调， 该 预设的延时为发送传输信号的发射装置复用的支路数目与该发射装置复用后的信号的码元周 期时间的乘积；
转换模块 1602， 用于将解调模块 1601解调后的光信号转换为电信号， 根据该电信号得 到传输信号的信息。
其中， 解调模块 1601可以具体为 MZI， 转换模块 1602可以具体为接收机， 包括平衡接 收机和普通的 PIN管等等。
本实施例中的接收端装置与现有技术中的接收端装置相比， 解调时延时的时间不同， 其 余均相同。 其中， 解调时延时的时间为发射端装置复用的支路数目与发射端装置复用后的信 号的码元周期时间的乘积， 比现有技术中延时的时间长， 扩大了解调器的延时范围。 例如， 采用 RZ-DQPSK光调制码型的 lOOGb/s光传输系统中， 如果发射端装置中复用器复用的支路 数目为 4， 则接收端装置解调时延时的时间为 4倍的码元周期时间， 即 80ps。
本实施例通过光接收装置按发射端装置复用后的信号的码元周期时间与发射端复用的支 路数目乘积的结果作为延时时间进行解调， 在解调时采用扩大的延时时间， 从而降低了系统 的实现难度。
实施例 4
参见图 17， 本发明实施例提供了一种光发射的方法， 具体包括：
步骤 1701 : 对待传输信号进行预编码； 其中， 预编码可以采用现有的预编码规则； 预编 码的过程可以具体为对待传输信号的各支路信号分别进行预编码， 得到多路编码数据；
步骤 1702: 对预编码得到的数据进行复用， 具体地， 可以对预编码得到的多路编码数据 进行复用， 如采用 EMUX对 4路 12.5Gb/s编码数据进行复用， 得到 1路 50Gb/s的信号； 步骤 1703 : 对复用后的信号进行调制； 其中， 调制可以采用多种调制器来实现， 如采用 双平行调制器、 电调制器或 MZM等等；
步骤 1704: 将调制后的光信号输出给光纤， 经光纤传输给接收端； 进一步地， 还可以采 用 RZ脉冲产生单元等将调制后的光信号转换为 RZ光脉冲信号，其中，调制后的光信号中非 相邻的光脉冲信号携带待传输信号的信息， 如调制后的光信号中非相邻的光脉冲信号之间的 相位变化携带待传输信号的信息。
由于在复用前先进行预编码，本实施例中预编码可以采用现有的普通的低速器件来实现。 本实施例通过在发射端先预编码然后进行复用， 可以保证在高速光传输系统中采用现有 的低速器件来实现高速的预编码功能， 从而降低了系统的实现难度， 且降低了系统的成本。
实施例 5
参见图 18， 本发明实施例还提供了一种光接收的方法， 具体包括：
步骤 1801 : 接收传输信号的光信号， 该光信号携带发射端的待传输信号的信息。
步骤 1802: 按预设的延时对收到的光信号进行解调， 如采用 MZI来进行解调， 预设的延 时为发送该传输信号的发射端装置复用的支路数目与该发射端装置复用后的信号的码元周期 时间的乘积;例如， 100Gb/S系统中复用的支路数目为 2，复用后的信号的码元周期时间为 20ps， 则接收端解调时的延时时间为 2倍的码元周期时间， 即 40pS;
步骤 1803 : 将解调后的光信号转换为电信号， 如用平衡接收机进行转换， 根据电信号得 到待传输信号的信息。 本实施例通过接收光脉冲信号时， 按发射端复用后的信号的码元周期时间与发射端复用 的支路数目乘积的结果的时间进行解调， 在解调时采用扩大的延时时间， 从而降低了系统的 实现难度。
本发明实施例可以利用软件实现， 相应的软件可以存储在可读取的存储介质中， 如光发 射装置的硬盘或光接收装置的硬盘中。
以上所述仅为本发明的较佳实施例， 并不用以限制本发明， 凡在本发明的精神和原则之 内， 所作的任何修改、 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 . 一种光传输系统， 其特征在于， 所述系统包括：
发射端装置， 用于对待传输信号先进行预编码， 然后对所述预编码得到的数据进行复用， 对所述复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非相邻 的光脉冲信号携带所述待传输信号的信息；
接收端装置， 用于接收所述发射端装置输出的光信号， 按预设的延时对所述光信号进行 解调， 将所述解调后的光信号转换为电信号， 根据所述电信号得到所述待传输信号的信息； 所述预设的延时为所述发射端装置复用的支路数目与所述发射端装置复用后的信号的码元周 期的乘积。
2. 根据权利要求 1所述的光传输系统， 其特征在于， 所述发射端装置具体包括： 预编码模块， 用于对待传输信号的各支路信号分别进行预编码， 得到多路编码数据； 复用模块， 用于对所述预编码模块得到的多路编码数据进行复用；
调制模块， 用于对所述复用模块复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非相邻的光脉冲信号携带所述待传输信号的信息。
3. 一种光发射装置， 其特征在于， 所述装置包括：
预编码模块， 用于对待传输信号进行预编码；
复用模块， 用于对所述预编码模块得到的数据进行复用；
调制模块， 用于对所述复用模块复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非相邻的光脉冲信号携带所述待传输信号的信息。
4. 根据权利要求 3所述的光发射装置， 其特征在于， 所述预编码模块具体包括： 预编码单元， 用于对待传输信号的各支路信号分别进行预编码， 得到多路编码数据。
5. 根据权利要求 3所述的光发射装置， 其特征在于， 所述复用模块具体为电复用器。
6.根据权利要求 3所述的光发射装置，其特征在于，所述调制模块具体为双平行调制器、 电调制器或马赫-泽德调制器。
7. 一种光接收装置， 其特征在于， 所述装置包括：
解调模块， 用于按预设的延时对所述装置收到的传输信号的光信号进行解调， 所述预设 的延时为发送所述传输信号的发射装置复用的支路数目与所述发射装置复用后的信号的码元 周期的乘积；
转换模块， 用于将所述解调模块解调后的光信号转换为电信号， 根据所述电信号得到所 述传输信号的信息。
8. 根据权利要求 7所述的光接收装置， 其特征在于， 所述解调模块具体为马赫-泽德干 涉仪。
9. 根据权利要求 7所述的光接收装置， 其特征在于， 所述转换模块具体为接收机。
10. 一种光发射的方法， 其特征在于， 所述方法包括：
对待传输信号进行预编码， 然后对所述预编码得到的数据进行复用；
对所述复用后的信号进行调制， 将所述调制后的光信号输出， 所述调制后的光信号中非 相邻的光脉冲信号携带所述待传输信号的信息。
11 .根据权利要求 10所述的光发射的方法，其特征在于，所述对待传输信号进行预编码， 然后对所述预编码得到的数据进行复用， 具体包括：
对待传输信号的各支路信号分别进行预编码， 得到多路编码数据；
然后对所述多路编码数据进行复用。
12. 一种光接收的方法， 其特征在于， 所述方法包括：
接收传输信号的光信号；
按预设的延时对所述光信号进行解调， 所述预设的延时为发送所述光信号的发射装置复 用的支路数目与所述发射装置复用后的信号的码元周期的乘积；
将所述解调后的光信号转换为电信号， 根据所述电信号得到所述传输信号的信息。
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