WO2014094255A1 - 光时域检测仪光模块及吉比特无源光网络断点检测系统 - Google Patents

光时域检测仪光模块及吉比特无源光网络断点检测系统 Download PDF

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Publication number
WO2014094255A1
WO2014094255A1 PCT/CN2012/086948 CN2012086948W WO2014094255A1 WO 2014094255 A1 WO2014094255 A1 WO 2014094255A1 CN 2012086948 W CN2012086948 W CN 2012086948W WO 2014094255 A1 WO2014094255 A1 WO 2014094255A1
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WIPO (PCT)
Prior art keywords
optical
signal
interface
laser
wavelength
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PCT/CN2012/086948
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English (en)
French (fr)
Inventor
张洪铭
张强
金成浩
赵其圣
杨思更
何鹏
薛登山
Original Assignee
青岛海信宽带多媒体技术有限公司
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Priority to PCT/CN2012/086948 priority Critical patent/WO2014094255A1/zh
Publication of WO2014094255A1 publication Critical patent/WO2014094255A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q11/0067—Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
    • 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
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/071—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using a reflected signal, e.g. using optical time domain reflectometers [OTDR]
    • 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
    • H04B10/27—Arrangements for networking
    • H04B10/272—Star-type networks or tree-type networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q11/00—Selecting arrangements for multiplex systems
    • H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
    • H04Q11/0062—Network aspects
    • H04Q2011/0079—Operation or maintenance aspects
    • H04Q2011/0083—Testing; Monitoring
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
    • H04Q2213/1301—Optical transmission, optical switches

Definitions

  • the present invention relates to optical fiber communication technologies, and in particular, to an optical time domain reflectometer (OTDR) optical module and a Gigabit Passive Optical Network (GPON) breakpoint detection system.
  • OTDR optical time domain reflectometer
  • GPON Gigabit Passive Optical Network
  • GPON has attracted much attention and has become the mainstream optical access method.
  • optical transmission media such as optical fiber/optical cables
  • Position usually using an optical time domain reflectometer (OTDR) optical module for breakpoint detection.
  • OTDR optical time domain reflectometer
  • the OTDR is a photoelectric integrated instrument made by Rayleigh scattering and Fresnel reflection when the light is transmitted in the optical fiber, and can be widely used in the maintenance and construction of the optical cable line. Measurement of fiber length, transmission attenuation of the fiber, joint attenuation, and fault location.
  • FIG. 1 is a schematic structural diagram of a conventional Gigabit passive optical network system.
  • the system includes: an optical line termination (OLT), a splitter (Splitter), and an optical network unit (ODU, Optical Net Unit), where
  • OLT optical line termination
  • Splitter splitter
  • ODU optical network unit
  • the OLT is usually set in the central office of the access network system of the optical fiber communication system, and the OLT is responsible for converting the electrical signal data in the external switch into optical signal data and transmitting it to the optical splitter, and receiving the optical signal transmitted by the optical splitter, and converting it into The electrical signal is delivered to an external switch;
  • the OLT is connected to the ONU through the Splitter.
  • the ONU is usually set at the central office, that is, the client or the building.
  • the splitter generally has 2N equalized interfaces. If the input interface has a light intensity of 1, the light intensity of each output interface is 1/. N.
  • an OLT is usually placed in the telecom central office, and then through the optical splitter, usually at least 1 minute 32, that is, an OLT passes
  • the splitter with 32 ONUs, constitutes a gigabit passive optical network system.
  • the number of ONUs is three. Assume that there is a 10km long fiber between the OLT and the splitter. The distance between the splitter and the ONU1 is 1km, and the distance between the splitter and the ONU2 is 2km. The spiler is The distance between ONU3 is 10km.
  • the OTDR technology is needed for the breakpoint detection, so as to detect the location of the fault in time. Carry out maintenance.
  • FIG. 2 is a schematic structural diagram of a conventional Gigabit passive optical network breakpoint detection system.
  • the system includes: an OTDR, a splitter, and an optical network unit (ODDU), wherein the optical time domain is performed with respect to the Gigabit passive optical network system shown in FIG.
  • ODDU optical network unit
  • the connection between the OLT and the fiber needs to be disconnected, and the OTDR is connected to the GPON system, that is, the OLT is replaced by the OTDR, and connected to the spreader through the optical fiber.
  • the OTDR transmits a light pulse through the transmitting interface, outputs it to the fiber, and transmits it to the ONU through the splitter.
  • a light pulse When a light pulse is transmitted within an optical fiber, it will scatter and reflect due to the nature of the fiber itself, as well as connectors, joints, bends, or other similar events. A portion of the scattered and reflected light is returned to the OTDR through the fiber, returning Useful information is measured by detectors in the OTDR and used as time or curve segments at different locations within the fiber. The analysis of time or curve segments allows the location of the breakpoint to be determined. That is, the OTDR uses Rayleigh scattering and Fresnel reflection to characterize the fiber. Rayleigh scattering is formed by the irregular scattering of optical signals along the fiber. These backscatter signals indicate the fiber.
  • the resulting attenuation (loss/distance) thus, by measuring a portion of the scattered light returned to the OTDR receiving interface, the degree of attenuation (loss/distance) of the fiber can be obtained;
  • Fresnel reflection is a discrete reflection, which is the entire Caused by individual points in the fiber, these points are caused by factors that cause the inverse coefficient to change, at which point strong backscattered light is reflected back. Therefore, the OTDR can locate connection points, fiber terminations or breakpoints by using Rayleigh scattering and Fresnel reflection information.
  • the existing GPON breakpoint detection system based on optical time domain detector for fiber breakpoint detection needs to disconnect the existing GPON system and then connect the OTDR to the breakpoint during the breakpoint detection process.
  • the detection system uses the OTDR to emit optical pulses into the optical fiber, and uses the Rayleigh scattering of the optical pulse and the information of the Fresnel reflection to detect the breakpoint detection process.
  • the OLT needs to be disconnected, thereby affecting Other normal transmission of network signals without breakpoints. For example, in the above example, when the fiber between the spilter and the ONU3 is broken, the OLT needs to be disconnected from the network during the detection, thereby causing the ONU 1.
  • the ONU2 signal transmission and reception is interrupted, which affects the normal operation of the GPON system. Moreover, in the case of frequent failure of the GPON system, the operation of disconnecting the OLT and plugging in the OLT is frequently performed, and frequent plugging is performed, so that the operational reliability of the OLT is lowered. .
  • Embodiments of the present invention provide an OTDR optical module, a streamlined breakpoint detection process, and a normal transmission of a network signal of a security system.
  • Embodiments of the present invention also provide a GPON breakpoint detection system, a streamlined breakpoint detection process, and a normal transmission of a system network signal.
  • an OTDR optical module including: an optical path component, a laser emitter, a laser detector, a breakpoint detecting module, and an electrical signal sampling circuit, where
  • the optical path component is connected to the optical fiber connected to the external optical line terminal OLT through the built-in upstream optical fiber interface, and is connected to the optical fiber connected to the external optical component through the built-in downstream optical fiber interface, and is connected to the laser transmitter through the built-in laser transmitting interface.
  • a built-in laser receiving interface is connected to the laser detector;
  • a laser emitter configured to generate an optical signal of a third wavelength for detecting a breakpoint when the breakpoint is detected, and output to a laser emitting interface of the optical path component;
  • a laser detector configured to receive an optical signal of a third wavelength outputted from a laser receiving interface of the optical path assembly, and convert the received optical signal of the third wavelength into a corresponding electrical signal output;
  • An electric signal sampling circuit is provided for connecting with the laser detector, sampling the electric signal outputted by the laser detector, obtaining a digital signal, and transmitting the signal to the breakpoint detecting module;
  • the breakpoint detection module is configured to receive the digital signal sent by the electrical signal sampling circuit, perform analysis, compare the analysis result with the previously obtained result of the analysis without the breakpoint sampling, and obtain the position of the breakpoint or the fault point.
  • the optical path component receives the optical signal of the first wavelength output by the external OLT through the optical fiber through the uplink optical fiber interface, transmits the optical signal to the optical fiber through the downlink optical fiber interface, and transmits the optical signal to the external optical component through the downstream optical fiber interface; and receives the external optical network unit ONU through the optical fiber interface.
  • the second wavelength optical signal is transmitted to the optical fiber through the upstream optical fiber interface and transmitted to the OLT;
  • the optical signal sampling circuit is further configured to perform amplification and filtering processing on the received electrical signal after receiving the electrical signal output by the laser detector.
  • the optical path assembly includes: a wavelength division multiplexer and a circulator, wherein
  • the WDM receives the optical signal of the first wavelength output by the OLT through the optical fiber through the built-in uplink optical interface, transmits the optical signal to the optical fiber through the downlink optical interface, and transmits the optical signal to the optical splitter; and receives the optical signal of the second wavelength output by the ONU through the optical fiber through the downlink optical interface. Passing through the optical fiber interface to the optical fiber and transmitting to the OLT;
  • the circulator is configured to receive the optical signal of the third wavelength emitted by the laser emitter through the built-in first interface, output to the reflective interface of the WDM through the built-in second interface, and receive the reflected output of the reflective interface of the WDM through the second interface
  • the optical signal of the third wavelength is output to the laser detector through a built-in laser receiving interface.
  • the optical path assembly further comprises a filter disposed between the laser receiving interface of the circulator and the laser detector, the filter for enhancing the third wavelength output from the laser receiving interface of the circulator Light signal.
  • the laser transmitter comprises: a laser emitting unit and a driving circuit unit, wherein the driving circuit unit is configured to drive the laser emitting unit to emit laser light of a third wavelength and output to the circulator when starting the breakpoint detection The first interface.
  • the laser transmitter further comprises:
  • control unit configured to generate a breakpoint detection electrical signal after receiving the breakpoint detection command of the external device, and output the signal to the driving circuit unit, so that the driving circuit unit detects the electrical signal according to the received breakpoint, and drives the laser emitting unit to emit The third wavelength of the laser.
  • the laser emitting unit is a 1625 nm distributed feedback laser emitting light source.
  • the laser detector comprises: a photodiode and a transimpedance amplifier TIA, wherein the photodiode is configured to receive an optical signal output from the laser receiving interface and output a corresponding response current to the TIA;
  • the TIA is configured to receive a response current, and output a corresponding differential electrical signal to the electrical signal sampling circuit according to the received response current.
  • the photodiode is an avalanche photodiode.
  • the electrical signal sampling circuit comprises:
  • the analog-to-digital conversion ADC circuit is configured to sample the electrical signal output by the laser detector, and send the sampled digital signal to the breakpoint detection module for storage.
  • the electrical signal sampling circuit further comprises an amplifying circuit disposed between the laser detector and the ADC circuit to amplify the electrical signal output by the laser detector.
  • the breakpoint detection module includes: a detection signal storage unit, a comparison unit, a normal operation signal storage unit, and a breakpoint position determining unit, where
  • a detection signal storage unit for storing a digital signal output by the ADC circuit in a detection state
  • a normal operation signal storage unit for storing a digital signal obtained by the Gigabit passive optical network breakpoint detection system in a normal operating state
  • a comparison unit configured to compare the digital signal stored by the detection signal storage unit with the digital signal stored by the normal operation signal storage unit, and output a comparison result
  • the breakpoint position determining unit is configured to analyze the comparison result output by the comparing unit to obtain the position of the breakpoint or the fault point.
  • the breakpoint detection module is a field programmable gate array, a programmable array logic, a single chip machine, a processor or a micro controller.
  • a gigabit passive optical network breakpoint detection system the system includes: an optical line terminal OLT, a beam splitter, and an optical network unit ONU, wherein the OLT transmits an optical signal of a first wavelength, and receives the transmitted by the ONU a second wavelength optical signal; the Gigabit passive optical network breakpoint detection system further includes: an optical time domain detector optical module,
  • the OLT is connected to the optical module of the optical time domain detector, and the optical module of the optical time domain detector is connected to the optical splitter; the optical module of the optical time domain detector is configured to receive the optical signal of the first wavelength output by the OLT, and transmit the optical signal to the optical splitter; The second wavelength optical signal output by the ONU is transmitted to the OLT; the third wavelength optical signal is generated, outputted, and the third wavelength optical signal returned by Rayleigh scattering and Fresnel reflection is received, and signal processing is performed according to signal processing. The result is to obtain breakpoint information.
  • the optical time domain detector optical module includes: an optical path component, a laser emitter, a laser detector, a breakpoint detecting module, and an electrical signal sampling circuit, wherein
  • the optical path component is connected to the optical fiber connected to the OLT through the built-in upstream optical fiber interface, connected to the optical fiber connected to the optical splitter through the built-in downstream optical fiber interface, connected to the laser transmitter through the built-in laser transmitting interface, and through the built-in laser receiving interface Connected to a laser detector;
  • a laser emitter configured to generate an optical signal of a third wavelength for detecting a breakpoint, and output the optical signal to the laser emitting interface of the optical path component
  • a laser detector configured to receive an optical signal of a third wavelength outputted from a laser receiving interface of the optical path assembly, and convert the received optical signal of the third wavelength into a corresponding electrical signal output
  • An electric signal sampling circuit is provided for connecting with the laser detector, sampling the electric signal outputted by the laser detector, obtaining a digital signal, and transmitting the signal to the breakpoint detecting module;
  • the breakpoint detection module is configured to receive the digital signal sent by the electrical signal sampling circuit, perform analysis, compare the analysis result with the previously obtained result of the analysis without the breakpoint sampling, and obtain the position of the breakpoint or the fault point.
  • the optical path component receives the optical signal of the first wavelength output by the OLT through the optical fiber through the uplink optical fiber interface, transmits the optical signal to the optical fiber through the downlink optical fiber interface, and transmits the optical signal to the optical splitter; and receives the optical signal of the second wavelength output by the ONU through the optical fiber through the downlink optical fiber interface. Transmitting to the optical fiber through the upstream optical fiber interface and transmitting to the OLT;
  • the optical path assembly includes: a wavelength division multiplexer and a circulator, wherein
  • the WDM receives the optical signal of the first wavelength output by the OLT through the optical fiber through the built-in uplink optical interface, transmits the optical signal to the optical fiber through the downlink optical interface, and transmits the optical signal to the optical splitter; and receives the optical signal of the second wavelength output by the ONU through the optical fiber through the downlink optical interface. Passing through the optical fiber interface to the optical fiber and transmitting to the OLT;
  • the circulator is configured to receive the optical signal of the third wavelength emitted by the laser emitter through the built-in first interface, output to the reflective interface of the WDM through the built-in second interface, and receive the reflected output of the reflective interface of the WDM through the second interface
  • the optical signal of the third wavelength is output to the laser detector through a built-in laser receiving interface.
  • the optical path assembly further comprises a filter disposed between the laser receiving interface of the circulator and the laser detector, the filter for enhancing the third wavelength output from the laser receiving interface of the circulator Light signal.
  • the laser transmitter comprises: a laser emitting unit and a driving circuit unit, wherein the driving circuit unit is configured to drive the laser emitting unit to emit when starting the breakpoint detection A three-wavelength laser is output to the first interface of the circulator.
  • the laser transmitter further comprises:
  • control unit configured to generate a breakpoint detection electrical signal after receiving the breakpoint detection command of the external device, and output the signal to the driving circuit unit, so that the driving circuit unit detects the electrical signal according to the received breakpoint, and drives the laser emitting unit to emit The third wavelength of the laser.
  • the laser detector comprises: a photodiode and a transimpedance amplifier TIA, wherein the photodiode is configured to receive an optical signal output from the laser receiving interface and output a corresponding response current to the TIA;
  • the TIA is configured to receive a response current, and output a corresponding differential electrical signal to the electrical signal sampling circuit according to the received response current.
  • the electrical signal sampling circuit comprises:
  • An analog-to-digital conversion ADC circuit for sampling an electrical signal output by the laser detector, and transmitting the sampled digital signal to a breakpoint detection module for storage;
  • the amplifying circuit is disposed between the laser detector and the ADC circuit to amplify the electrical signal output by the laser detector.
  • the breakpoint detection module includes: a detection signal storage unit, a comparison unit, a normal operation signal storage unit, and a breakpoint position determining unit, where
  • a detection signal storage unit for storing a digital signal output by the ADC circuit in a detection state
  • a normal operation signal storage unit for storing a digital signal obtained by the Gigabit passive optical network breakpoint detection system in a normal operating state
  • a comparison unit configured to compare the digital signal stored by the detection signal storage unit with the digital signal stored by the normal operation signal storage unit, and output a comparison result
  • the breakpoint position determining unit is configured to analyze the comparison result output by the comparing unit to obtain the position of the breakpoint or the fault point.
  • the OTDR optical module and the GPON breakpoint detection system of the embodiment of the invention include: an optical line terminal OLT, a beam splitter, an optical network unit ONU, and an optical time domain detector optical module, OLT and optical time domain detection.
  • the optical module is connected to the optical module, and the optical module of the optical time domain detector is connected to the optical splitter; the optical module of the optical time domain detector is configured to receive the optical signal of the first wavelength output by the OLT, and transmit the optical signal to the optical splitter; and receive the second wavelength of the output of the ONU.
  • the optical signal is transmitted to the OLT; the optical signal of the third wavelength is generated, outputted, and the optical signal of the third wavelength returned by the Rayleigh scattering and the Fresnel reflection is received, and signal processing is performed, and the breakpoint information is obtained according to the signal processing result.
  • breakpoint detection there is no need to disconnect the OLT, so that normal service communication in the GPON is not affected, and the system network signal is guaranteed.
  • the breakpoint detection process is compressed; further, since the operation of disconnecting the OLT and plugging the OLT is not frequently performed, the frequent insertion of the OLT is reduced, and the operational reliability of the OLT is improved.
  • FIG. 1 is a schematic structural diagram of a conventional Gigabit passive optical network system.
  • FIG. 2 is a schematic structural diagram of a conventional Gigabit passive optical network breakpoint detection system.
  • FIG. 3 is a schematic structural diagram of a Gigabit passive optical network breakpoint detection system according to an embodiment of the present invention.
  • FIG. 4 is a schematic structural diagram of an optical module of an optical time domain detector according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of detecting a Gigabit passive optical network breakpoint detection system according to an embodiment of the present invention.
  • Figure 6 is a schematic diagram of the waveform of a digital signal stored in a breakpoint detection module.
  • Figure 7 is a schematic diagram of the digital signal waveform and distance calculated based on Figure 6.
  • a module can be, but is not limited to: a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer.
  • an application running on a computing device and this computing device can be modules.
  • One or more modules may be located within a process and/or thread of execution, and a module may be located on one computer and/or distributed between two or more computers.
  • the OLT In the existing GPON breakpoint detection system, in the process of performing breakpoint detection, the OLT needs to be disconnected first, and then the OTDR is connected to the breakpoint detection system for breakpoint detection, and after the detection is completed, the OTDR is disconnected, and The OLT accesses the system for normal communication, which makes the breakpoint detection process more complicated and affects the normal transmission of network signals.
  • an online OTDR optical module is provided, and breakpoint detection is performed without disconnecting the OLT, and the OTDR optical module is connected in series to the Gigabit passive optical network system, and the downlink of the OLT is outputted.
  • the optical signal and the uplink optical signal transmitted to the OLT are transparently transmitted, and the optical signal transmitted by the OTDR optical module is received by the optical signal.
  • the OTDR detection light returned by the reflection, the breakpoint analysis is performed, and the result of the breakpoint analysis is fed back to the system, and has the advantages of low price, single operation tube, hot swappable, easy replacement, and maintenance.
  • FIG. 3 is a schematic structural diagram of a Gigabit passive optical network breakpoint detection system according to an embodiment of the present invention.
  • the system includes: an optical line terminal (OLT) 301, a splitter 302, an optical time domain detector optical module 303, and an optical network unit (ONU) 304, wherein the OLT 301, the optical splitter 302, and the optical network
  • the unit ONU 304 is the same as the OLT, splitter and ONU in the prior art PON system;
  • the OLT 301 is connected to the optical time domain detector optical module 303, and the optical time domain detector optical module 303 is connected to the optical splitter 302.
  • the optical splitter 302 is connected to one or more ONUs 304, that is, the optical time domain detector optical module 303 is connected in series to the OLT 301. Between with splitliter302. Specifically, the OLT 301 is connected to the optical time domain detector optical module 303 through an optical fiber, and the optical time domain detector optical module 303 is connected to the optical splitter 302 through an optical fiber, and the optical splitter 302 is connected to one or more ONUs 304 through an optical fiber.
  • the optical time domain detector optical module 303 is located closer to the OLT 301 in the Gigabit passive optical network breakpoint detection system.
  • the OLT 301 is configured to transmit an optical signal of the first wavelength (downlink communication optical signal), enter the optical time domain detector optical module 303 via the optical fiber, and transmit the optical module 303 to the optical splitter 302 by the optical time domain detector;
  • the second wavelength optical signal (uplink communication optical signal) transmitted by the domain detector optical module 303 is processed;
  • the OLT 301 transmits the transmitted optical signal of the first wavelength to the uplink optical fiber interface of the optical time domain detector optical module 303 through the optical fiber, and enters the optical fiber through the downlink optical interface of the optical time domain detector optical module 303.
  • the optical splitter 302 After being transmitted in the optical fiber, the optical splitter 302 is received; and the optical signal of the second wavelength transmitted by the optical fiber interface of the optical time domain detector optical module 303 is received by the optical fiber for processing.
  • the specific processing procedure of the optical signal of the OLT 301 is the same as that of the prior art.
  • the specific processing procedure of the optical signal of the OLT 301 is the same as that of the prior art.
  • the optical time domain detector optical module 303 is configured to receive the optical signal of the first wavelength output by the OLT 301, and transmit the optical signal to the optical splitter 302.
  • the optical signal of the second wavelength output by the ONU 304 is received and transmitted to the OLT 301.
  • the optical signal of the third wavelength is generated. And performing an output, receiving the optical signal of the third wavelength returned by the Rayleigh scattering and the Fresnel reflection, performing signal processing, and acquiring the breakpoint signal according to the signal processing result.
  • the optical time domain detector optical module 303 receives the signal.
  • the optical signal is judged to determine whether it is an optical signal of a first wavelength, an optical signal of a second wavelength, or an optical signal of a third wavelength, For details, refer to related technical documents, and details are not described herein again.
  • the optical signal of the third wavelength returned by Rayleigh scattering and Fresnel reflection may be returned by Rayleigh scattering and Fresnel reflection on the communication link between the optical time domain detector optical module 303 and the optical splitter 302.
  • the optical signal may also be an optical signal returned by Rayleigh scattering and Fresnel reflection on the beam splitter 302, or may be returned by Rayleigh scattering and Fresnel reflection on the communication link between the optical splitter 302 and the ONU 304.
  • the optical signal may also be an optical signal on the ONU 304 that is returned by Rayleigh scattering and Fresnel reflection.
  • the optical splitter 302 is configured to receive the optical signal outputted by the optical time domain detector optical module 303, perform spectral processing, and output to one or more ONUs 304 connected to itself, and receive the optical signals of the second wavelength generated by the ONU 304 to perform converging. Processing, outputting to the optical time domain detector optical module 303; receiving the optical signal of the third wavelength through Rayleigh scattering and Fresnel reflection, performing a sinking process, and outputting to the optical time domain detector optical module 303;
  • the optical splitter 302 is configured to perform spectral processing on the downlink optical signal sent to the ONU 304, and perform a convergence process on the received upstream optical signal, and output the optical signal to the optical time domain detector optical module 303.
  • the ONU 304 is configured to receive the optical signal of the first wavelength through the optical fiber, and after processing, generate an optical signal of the second wavelength, and output the optical signal to the optical splitter 302; receive the optical signal of the third wavelength, and pass the Rayleigh scattering and the Fresnel reflection The optical signal of the third wavelength is output to the beam splitter 302 through the optical fiber.
  • the detailed process of the ONU 304 receiving the optical signal of the first wavelength through the optical fiber and performing the processing to generate the optical signal of the second wavelength belongs to the prior art. For details, refer to related technical documents.
  • the ONU 304 If the ONU 304 receives the optical signal of the third wavelength through the optical fiber, it indicates that the communication link between the optical time domain detector optical module 303 and the ONU 304 is normal; if the optical time domain detector optical module 303 outputs the optical signal of the third wavelength, The ONU 304 does not receive the optical signal of the third wavelength, indicating that the communication link between the optical time domain detector optical module 303 and the ONU 304 has an abnormality.
  • the OLT 301 transmits the optical signal of the first wavelength (downlink communication optical signal), enters the optical fiber between the OLT 301 and the optical time domain detector optical module 303, and transmits the optical time domain detector light after being transmitted in the optical fiber.
  • the optical fiber interface between the optical time domain detector optical module 303 and the optical splitter 302 enters the optical fiber between the optical time domain detector optical module 303 and the optical splitter 302.
  • the second wavelength optical signal (uplink communication optical signal) passes through the optical fiber between the optical splitter 302, the optical splitter 302 and the optical time domain detector optical module 303, and enters the downstream optical fiber interface of the optical time domain detector optical module 303.
  • the optical fiber interface of the optical time domain detector optical module 303 After the transmission of the optical time domain detector optical module 303, the optical fiber interface of the optical time domain detector optical module 303 enters the optical fiber, and after being transmitted in the optical fiber, it reaches the OLT 301, and the OLT 301 receives the optical signal of the second wavelength for processing, according to the optical
  • the signal processing result emits an optical signal of a first wavelength (downlink communication optical signal), and thus cycles until the end of the process;
  • the optical time domain detector optical module 303 transmits the optical signal of the third wavelength through the downlink optical fiber interface, and sequentially passes the optical fiber and the optical split between the optical time domain detector optical module 303 and the optical splitter 302.
  • the optical fiber between the optical fiber 302 and the ONU 304 and the link of the ONU 304 are optically transmitted. If a breakpoint occurs in the link, the optical signal of the third wavelength is reflected from the breakpoint and reversely passes through the link.
  • the optical fiber interface of the optical time domain detector optical module 303 receives the reflected optical signal of the third wavelength, the reflected optical signal of the third wavelength is converted into an electrical signal. Sampling, analog-to-digital conversion, digital signals are obtained, and the sampled digital signals are stored and analyzed to determine the position of the breakpoint or the fault point.
  • the optical time domain detector optical module 303 is configured to perform breakpoint detection, and the OLT 301 may not receive the optical signal in response to the first wavelength after the optical signal of the first wavelength is received within a preset time.
  • the optical signal of the second wavelength is sent to the optical time domain detector optical module 303 to trigger the break detection of the start time optical field detector optical module 303, or the optical time domain detector optical module 303 is periodically transmitted.
  • the three-wavelength optical signal performs breakpoint fault detection based on the reflected third wavelength optical signal.
  • optical time domain detector optical module 303 various types of detection parameters are set, for example, the fiber refractive index n, the optical pulse wavelength, and the like.
  • detection parameters for example, the fiber refractive index n, the optical pulse wavelength, and the like.
  • the optical time domain detector optical module 303 analyzes the information of the backscattered light feedback at different positions of the optical fiber, forms a waveform on the liquid crystal display, and analyzes the waveform to obtain a position where the optical fiber is faulty. .
  • the third wavelength of the optical signal emitted by the optical time domain detector optical module 303 may be the same as the optical signal of the first wavelength and the optical signal of the second wavelength (upstream and downward optical waves), for example, commonly used.
  • the 10G downstream optical wavelength is 1577 nm
  • the 2.5G upstream optical wavelength is 1270 nm
  • the 2.5G downstream optical wavelength is 1490 nm
  • the 1G upstream optical wavelength is 1310 nm.
  • the wavelength of light selected for OTDR breakpoint detection is 1625 nm.
  • the optical time domain detector optical module 303 acts as a repeater, and performs no processing on the received optical signal, and forwards to the next receiving unit.
  • the optical time domain detector optical module 303 connected in series between the OLT 301 and the optical splitter 302 can transmit communication signals in the GPON system, for example, the optical signal of the downlink communication of the first wavelength and the second wavelength.
  • the optical signal of the uplink communication in the flow of the breakpoint detection, realizes the transmission of the communication data, so that the presence of the optical time domain detector optical module 303 does not affect the communication of the existing GPON system.
  • the optical module includes: an optical path component 401, a laser transmitter 402, a laser detector 403, a breakpoint detection module 405, and an electrical signal sampling circuit 404, where
  • the optical path component 401 is configured to be connected to the optical fiber connected to the OLT 301 through the built-in upstream optical fiber interface, connected to the optical fiber connected to the optical splitter 302 through the built-in downstream optical fiber interface, and connected to the laser transmitter 402 through the built-in laser transmitting interface, through the built-in
  • the laser receiving interface is connected to the laser detector 403;
  • the optical path component 401 receives the optical signal of the first wavelength output by the OLT 301 through the optical fiber through the uplink optical fiber interface, transmits the optical signal to the optical fiber through the downlink optical fiber interface, and transmits the optical signal to the optical splitter 302; and receives the output of the ONU 304 through the optical fiber through the downlink optical fiber interface.
  • the two-wavelength optical signal is transmitted to the optical fiber through the uplink optical fiber interface and transmitted to the OLT 301;
  • the optical path component 401 includes four interfaces, namely: an uplink optical fiber interface, a downlink optical fiber interface, a laser transmitting interface, and a laser receiving interface, wherein the uplink optical fiber interface and the downstream optical fiber interface are respectively connected to the optical fiber, that is, the uplink optical fiber.
  • the interface is connected to the OLT 301 through an optical fiber, and the downstream optical fiber interface is connected to the optical splitter 302 through the optical fiber.
  • the optical path component 401 receives the optical signal of the third wavelength emitted by the laser transmitter 402 through the laser transmitting interface, and transmits the laser transmitter 402 after coupling.
  • the three-wavelength optical signal is output from the downstream fiber interface to the optical fiber for transmission.
  • the optical signal of the third wavelength is transmitted in the optical fiber of the GPON system, and is reflected at the break point of the optical fiber or the fault of the device (for example, the optical splitter and the ONU) or other faulty place, and is reflected third.
  • the optical signal of the wavelength is transmitted in the optical fiber and returned to the optical path component 401.
  • the optical path component 401 receives the reflected optical signal of the third wavelength from the downstream optical fiber interface, and after the optical splitting process, outputs the reflected optical signal of the third wavelength to the laser detector 403 through the laser receiving interface.
  • a laser transmitter 402 configured to generate a third wavelength optical signal for detecting a breakpoint, and output the optical signal to the laser emitting interface of the optical path assembly 401;
  • the pulse electrical signal of the fixed period may be electrically and optically converted to generate an optical signal of a third wavelength and transmitted.
  • the laser detector 403 is configured to receive the optical signal of the third wavelength outputted from the laser receiving interface of the optical path component 401, and convert the received optical signal of the third wavelength into a corresponding electrical signal output.
  • the laser detecting The optical signal of the third wavelength received by the device 403 is a reflected signal, and the reflected signal can reflect the position of the breakpoint in the network fiber. After converting the reflected optical signal into an electrical signal and sampling, the sampled digital signal is analyzed. You can determine the location of the breakpoint or fault point.
  • the electrical signal sampling circuit 404 is configured to be connected to the laser detector 403, and sample the electrical signal output by the laser detector 403 to obtain a digital signal, and send it to the breakpoint detecting module 405.
  • the electrical signal sampling circuit The 404 can also amplify and filter the electrical signal output by the laser detector 403, and then sample the amplified and filtered electrical signals to output the sampled digital signals.
  • the breakpoint detection module 405 is configured to receive the digital signal sent by the electrical signal sampling circuit 404, perform analysis, and compare the analysis result with the previously obtained non-breakpoint sampling analysis to obtain a breakpoint or a fault point position.
  • the breakpoint detection module 405 can also be used to store the digital signal sent by the received electrical signal sampling circuit 404.
  • the breakpoint detection module 405 generates a first waveform based on the digital signal received and stored from the electrical signal sampling circuit 404, and compares it with a pre-stored second waveform generated from the digital signal sampled without the breakpoint, according to the comparison. As a result, the position of the breakpoint or the fault point is judged.
  • the received digital signal can also be compared with a pre-stored digital signal.
  • the pre-stored digital signal is under normal conditions, that is, without a breakpoint or a fault-free point.
  • a sampled digital signal obtained by sampling and analog-to-digital conversion of a three-wavelength optical signal.
  • the external pins of the optical time domain detector optical module 303 may specifically include:
  • SDA pin which is the serial communication line data pin
  • SCL pin which is the serial communication line clock pin; GND and VCC pins.
  • the SDA pin and the SCL pin are connected to the breakpoint detecting module 405, and the control unit 1202 communicates with an external device through the SDA pin and the SCL pin.
  • the electrical interface of the external pin of the optical time domain detector optical module 303 can be a pin-type 4pin structure.
  • the analysis result is compared with the result obtained by analyzing the sample without the breakpoint in advance, and the position of the breakpoint or the fault point is obtained as a prior art.
  • the related technical literature and no longer like this. Said.
  • Here is just a brief introduction to the principle.
  • FIG. 5 is a schematic diagram of detecting a Gigabit passive optical network breakpoint detection system according to an embodiment of the present invention. Referring to Figure 5, it is assumed that there is a 10km long optical fiber between the optical module and the optical splitter. The distance between the optical splitter and the ONU1 is 1km, and the distance between the optical splitter and the ONU2 is 2km. The distance between ONU3 is 10km, but fiber breakage occurs at 7km.
  • the laser emitter 402 of the optical time domain detector optical module When performing breakpoint detection (communication service can be performed normally), the laser emitter 402 of the optical time domain detector optical module emits an optical signal of a wavelength of 1625 nm, which is output to the laser emitting interface of the optical path assembly 401, and the laser transmitting interface receives the 1625 nm.
  • the optical signal of the wavelength is output to the downstream optical fiber interface, and is output to the optical splitter by the downstream optical fiber interface, and is split and processed by the optical splitter, and then output separately.
  • the optical signal of the wavelength of 1625 nm When the optical signal of the wavelength of 1625 nm is transmitted to the optical splitter and the distance between the optical splitter and the ONU 3 is 7 km, The optical fiber is broken, and the optical signal of the wavelength of 1625 nm is reflected at the break, and is reflected back to the optical splitter by the optical fiber. After the optical splitter is reflowed, it is transmitted to the optical module of the optical time domain detector, and the optical fiber interface of the optical module of the optical time domain detector receives the optical signal.
  • the received optical signal is an optical signal having a wavelength of 1625 nm, outputting to the laser receiving interface, and outputting to the laser detector 403 by the laser receiving interface; the laser detector 403 converting the received optical signal into an electrical signal and passing the electrical signal
  • the sampling circuit 404 samples the digital signal and stores it in the breakpoint detection module 405.
  • Figure 6 is a schematic diagram of the waveform of a digital signal stored in a breakpoint detection module.
  • the abscissa is time, and the ordinate is the received optical power (dbm).
  • the optical module of the optical time domain detector emits light
  • the reflected peaks of the optical signals are received at the time points T1 - T4 respectively, then the reflections are
  • the distance of the light from the optical module of the optical line terminal is calculated according to the following formula:
  • FIG. 7 is a schematic diagram of a digital signal waveform and distance calculated based on FIG. 6.
  • the abscissa is the distance from the optical module at the end of the optical line, and the ordinate is the received optical power (dbm).
  • the optical module in the distance time domain detector At 10km, due to the reflection of the beam splitter, a Fresnel reflection peak is detected. At 11km from the optical detector of the optical time domain detector, the reflection peak of ONU1 is detected.
  • the reflection peak to the ONU2 at a distance of 17 km from the optical detector of the optical time domain detector, detects the reflection peak at the reflected light (the break of the fiber).
  • the result is obtained: At a distance of 10 km from the optical detector of the time domain detector, a reflection peak is detected due to the reflection of the beam splitter. At 11km from the optical module of the optical time domain detector, the reflection peak of ONU1 is detected due to the reflection of ONU1. At 12km from the optical module of the optical time domain detector, the reflection peak of ONU2 is detected due to the reflection of ONU2. At 20km from the optical module of the optical time domain detector, the reflection peak of the ONU3 is detected due to the reflection of the ONU3.
  • the signal waveform shown in FIG. 7 does not include the reflection peak of the ONU 3, it is determined that a break point occurs between the link between the beam splitter and the ONU 3, and the break point is away from the optical time domain detector optical module. 17km.
  • the optical path component 401 includes: a wavelength division multiplexer (WDM) and a circulator 412, wherein
  • WDM wavelength division multiplexer
  • the WDM411 has three interfaces, namely a common interface (COM interface), a transmission interface (Pass interface), and a reflection interface (Slip interface).
  • COM interface common interface
  • Pass interface transmission interface
  • Slip interface reflection interface
  • the COM interface of the WDM411 is connected to the optical fiber as the downstream optical interface of the optical path component 401, and the passive interface of the WDM411 is used as the optical fiber interface of the optical path component 401 to access the optical fiber.
  • the Reflect interface of the WDM411 is connected to the circulator 412.
  • the WDM411 receives the optical signal of the first wavelength output by the OLT 301 through the optical fiber through the uplink optical fiber interface, transmits the optical signal to the optical fiber through the downlink optical fiber interface, and transmits the optical signal to the optical splitter 302 through the downstream optical fiber interface, and receives the optical signal of the second wavelength output by the ONU 304 through the optical fiber through the downlink optical fiber interface. Transmitted to the optical fiber through the uplink optical fiber interface and transmitted to the OLT 301;
  • WDM is introduced to realize this function.
  • the downlink optical interface of the WDM411 receives the optical signal of the second wavelength and the optical signal of the third wavelength, and performs detailed processing of the wavelength division multiplexing. For details, refer to the related technical documents, and details are not described herein again.
  • the circulator 412 has three interfaces, which are respectively a first interface, a second interface, and a third interface; the second interface of the circulator 412 is connected to the Reflect interface of the WDM 411; for example, the second interface of the circulator 412 and the Reflect interface of the WDM 411 It can be connected through fiber optics, or the two interfaces can be directly connected.
  • the first interface and the third interface of the circulator 412 serve as a laser emitting interface and a laser receiving interface of the optical path assembly 401, respectively;
  • the circulator 412 is configured to receive the optical signal of the third wavelength emitted by the laser transmitter 402 through the laser transmitting interface, output to the Reflect interface of the WDM 411 through the second interface, and receive the third reflected output of the Reflect interface of the WDM 411 through the second interface.
  • the optical signal of the wavelength is output to the laser detector 403 through the laser receiving interface.
  • the circulator 412 is configured to separate the emitted light from the reflected light, that is, the 1625 nm laser light emitted by the laser emitter 402 is input by the first interface and output by the second interface;
  • the 1625 nm probe light (reflected light) is output from the third interface and supplied to the laser detector 403.
  • the optical signal of the third wavelength emitted by the laser transmitter 402 enters the circulator 412 of the optical path assembly 401 via the first interface (first interface) of the circulator 412, and exits from the second interface of the circulator 412;
  • the third wavelength optical signal enters the optical path component 401 via the COM interface of the WDM 411 and is output from the Reflect interface of the WDM 411 to the circulator 412.
  • the second interface of the circulator 412 receives the reflected third wavelength incident from the Reflect interface of the WDM 411.
  • the third interface of the circulator 412 enters the optical fiber and is transmitted to the laser detector 403.
  • the optical path component 401 may further include a third interface disposed between the third interface of the circulator 412 and the laser detector 403.
  • the filter 413 by adding a filter in front of the laser detector 403, increases the wavelength of light at 1625 nm, and blocks the wavelength of light below 1610 nm.
  • the filter 413 is an anti-reflection sheet for the third-wavelength optical signal, and is used for enhancing the optical signal of the third wavelength outputted from the third interface of the circulator 412, and the spurs in the tens of thousands of systems. wavelength.
  • the COM interface of the WDM411 can be transmitted.
  • the interface for transmitting the full-band optical signal, the Pass interface is an interface capable of transmitting the first and second wavelength optical signals, and the Reflect interface is an interface for reflecting the optical signal of the third wavelength.
  • the first wavelength is specifically 1490 nm; the second wavelength is 1310 nm; the third wavelength is 1625 nm, the Pass interface is designed to transmit optical signals of wavelengths below 1580 nm, and the Reflect interface is designed to reflect optical signals of wavelengths above 1610 nm.
  • Table 1 The specific indicators of WDM411 are shown in Table 1 below: Table 1
  • Pass -> Com means that the light wave enters from the PASS port and the COM port; both directions can indicate that the light wave can enter from the PASS port, the COM port, or the COM port, and the PASS port.
  • the insertion loss requirement is as small as possible to minimize the loss of the system; the isolation requirement is as high as possible to reduce crosstalk and improve the sensitivity of the system.
  • the laser transmitter 402 includes: a laser emitting unit and a driving circuit unit (not shown), wherein
  • the driving circuit unit is configured to drive the laser emitting unit to emit the laser of the third wavelength and output to the first interface of the circulator when starting the breakpoint detection.
  • the laser emitting unit may be a 1625 nm distributed feedback laser (DFB, Distribute Feed Back Laser) emitting light source, and converts the optical pulse signal into a burst emission optical signal.
  • DFB distributed feedback laser
  • the laser transmitter 402 can also include:
  • control unit configured to generate a breakpoint detection electrical signal after receiving the breakpoint detection command of the external device, and output the signal to the driving circuit unit, so that the driving circuit unit detects the electrical signal according to the received breakpoint, and drives the laser emitting unit to emit The third wavelength of the laser.
  • the laser detector 403 includes: a photodiode and a transimpedance amplifier (TIA, Tranimpedance Amplifier ) (not shown), where
  • a photodiode for receiving an optical signal output from the laser receiving interface, and outputting a corresponding response current to the ⁇ ;
  • the photodiode may specifically be an avalanche photodiode (APD) in the optical module.
  • APD avalanche photodiode
  • the electrical signal sampling circuit 404 includes: an analog to digital converter (ADC) circuit,
  • the ADC circuit is configured to sample the electrical signal output by the laser detector 403, and send the sampled digital signal to the breakpoint detection module 405 for storage.
  • the electrical signal sampling circuit 404 may further include an amplifying circuit disposed between the laser detector 403 and the ADC circuit, and amplifying the electrical signal output by the laser detector 403 to enable the ADC The circuit samples the amplified electrical signal of the amplifying circuit, and sends the sampled digital signal to the breakpoint detecting module 405 for storage.
  • the breakpoint detecting module 405 includes: a detection signal storage unit, a comparison unit, a normal operation signal storage unit, and a breakpoint position determining unit (not shown), wherein
  • a detection signal storage unit configured to store a digital signal normal operation signal storage unit outputted by the ADC circuit in the detection state, for storing a digital signal obtained by the Gigabit passive optical network breakpoint detection system in a normal operating state
  • a comparison unit configured to compare the digital signal stored by the detection signal storage unit with the digital signal stored by the normal operation signal storage unit, and output a comparison result
  • the breakpoint position determining unit is configured to analyze the comparison result output by the comparing unit to obtain the position of the breakpoint or the fault point.
  • the breakpoint position determining unit may be further configured to output the determined position information of the breakpoint or the fault point to a preset external device.
  • the breakpoint detection module 405 may be implemented by a logic array circuit, for example, a field programmable gate array (FPGA), a programmable array logic (PAL, Programmable Array Logic), or the like; or It can also be realized by a computing chip such as a single chip microcomputer, a processor, a micro controller, or the like. That is, the breakpoint detection module 405 can be an FPGA, a PAL, a microcontroller, a processor, or a microcontroller. In the case of breakpoint detection, the FPGA is installed in a flash (Flash) program, sends a pulse signal for breakpoint detection (shown by a broken line in Fig.
  • Flash flash
  • the transmitted electrical pulse signal is converted into an optical pulse signal of 1625 nm; the optical signal reflected back in the system is photoelectrically converted by the APD detector, and the optical signal is converted into a current signal, and then converted by a Transimpedance Amplifier (TIA).
  • TIA Transimpedance Amplifier
  • the processing of the op amp is input to the ADC circuit, and the analog signal is converted into a digital signal and then sent to the FPGA.
  • the FPGA analyzes and calculates the received digital signal to determine the position of the breakpoint.
  • the electrical interface of the optical time domain detector optical module 303 can adopt the lPOin structure of the Joint Test Action Group (JTAG) interface, wherein 4 pins are SDA and I 2 C for I 2 C data respectively.
  • the other 6 pins are used for the debug circuit.
  • the JTAG interface communicates with the external system analysis device, and the system reads the data of the FPGA through the I 2 C bus communication. Determine the fiber breakpoint location.
  • the 1490nm DFB laser in the GPON OLT is used as the downlink light source to transmit a continuous 2.488Gbps signal.
  • the 1310nm APD detector in the GPON OLT receives the uplink burst packet sent by the ONU. Data reception.
  • the built-in 1625nm DFB laser transmits a series of burst lasers, through the breakpoints in the fiber link, due to Rayleigh scattering and Fresnel During reflection, a portion of the return loss light is reflected back to the fiber, which in turn returns to the 1625nm APD detector built into the optical detector of the time domain detector.
  • the 1625nm APD detector receives the reflected light, photoelectrically converts it to form a current signal, and then passes through the op amp processing and ADC sampling, and transmits it to the FPGA as a digital signal.
  • the FPGA compares the received signal with the normal case signal stored in the Flash, and finds the position at which the breakpoint occurs, that is, the peak value of the signal relative to the normal signal.
  • the position corresponding to the peak is the position of the breakpoint, and passes through I.
  • the 2 C bus reads the data of the FPGA and knows where the breakpoint occurred.
  • the Gigabit passive optical network breakpoint detection system in the embodiment of the present invention connects the optical time domain detector optical module into the OLT and the optical splitter in the Gigabit passive optical network breakpoint detection system.
  • the optical time domain detector optical module can transmit the communication optical signal (the first wavelength optical signal and the second wavelength optical signal), and emit the breakpoint detection optical signal (the third wavelength The optical signal) performs breakpoint detection based on the reflected optical signal of the third wavelength to determine the position of the breakpoint.
  • the optical time domain detector optical module can save the equipment of the optical time domain reflectometer, and the circuit cost is low.
  • the utility model has the advantages of low price, simple operation, and easy operation. Maintenance and other advantages, so that the breakpoint detection of the passive optical network system is realized at low cost; Moreover, since the operation of disconnecting the OLT and plugging the OLT is not frequently performed, the frequent insertion of the 0LT is reduced, and the work of the OLT is improved. Sex.

Abstract

一种吉比特无源光网络断点检测系统，包括：光线路终端OLT（301）、分光器（302）、光网络单元ONU（304）以及光时域检测仪光模块（303），OLT（301）与光时域检测仪光模块（303）相连，光时域检测仪光模块（303）与分光器（302）相连；光时域检测仪光模块（303），用于接收OLT（301）输出的第一波长的光信号，透射至分光器（302）；接收ONU（304）输出的第二波长的光信号，透射至OLT（301）；生成第三波长的光信号，进行输出，接收瑞利散射和菲涅尔反射返回的第三波长的光信号，进行信号处理，根据信号处理结果获取断点信息。应用该系统可以简化断点检测流程、保障系统网络信号的正常传输。

Description

光时域检测仪光模块及吉比特无源光网络断点检测系统 技术领域
本发明涉及光纤通信技术， 尤其涉及一种光时域检测仪（OTDR, Optical Time Domain Reflectometer ) 光模块及吉比特无源光网络（ GPON, Gigabit Passive Optical Network ) 断点检测系统。 背景技术
目前的国内市场以及国际市场， 高带宽、 高速率和多种业务融合的光 纤通信方向已经开始应用； 在众多的解决方案中， 光纤到户 （FTTH, Fiber To The Home ) 的出现被认为是宽带接入的终极解决方案， 国内市场已经 大面积应用。
而在 FTTH众多方案中， 其中 GPON又备受关注， 成为了目前主流的 光接入方式。 在 GPON系统中， 光的传输介质， 如光纤 /光缆， 往往铺设在 郊外或者海底， 难免由于传输链路断点出现链路故障或者传输设备故障等 问题， 为了能够精确定位出现故障或者断点的位置， 通常采用光时域反射 仪（ OTDR, Optical Time Domain Reflectometer )光模块进行断点检测。 其 中， OTDR是利用光线在光纤中传输时的瑞利散射和菲涅尔反射所产生的 背向散射而制成的光电一体化仪表， 可以广泛应用于光缆线路的维护、 施 工之中， 可进行光纤长度、 光纤的传输衰减、 接头衰减和故障定位等的测 量。
图 1为现有吉比特无源光网络系统结构示意图。 参见图 1 , 该系统包 括： 光线路终端 （OLT, Optical Line Terminator ) 、 分光器 （Splitter ) 以 及光网络单元 （ODU, Optical Net Unit ) ， 其中，
OLT通常设置在光纤通信系统的接入网系统的中心局， OLT负责将外 部交换机中的电信号数据转化为光信号数据发送至分光器， 并且接收分光 器传送来的光信号， 将其转化为电信号输送给外部的交换机；
OLT通过 Splitter与 ONU相连， ONU通常设置在局端， 即用户端或 者大楼； Splitter—般有 2N 个均分接口， 如果输入接口的光强为 1 , 则每 个输出接口的光强为 1/N。
对于一个吉比特无源光网络系统（光接入系统）， 一般是一个 OLT放 在电信中心局， 然后通过分光器， 一般至少是 1分 32, 即一个 OLT通过 分光器， 带 32 ONU组成吉比特无源光网络系统。
图 1中， 以 ONU数量为三个为例， 假设从 OLT到 spliter之间， 有一 段 10km长的光纤， spliter到 ONU1之间的距离为 1km, spliter到 ONU2 之间的距离为 2km , spilter到 ONU3之间的距离为 10km。
假设在 spilter到 ONU3之间的光纤在 7km处发生了光纤断裂，则将使 得 OLT到 ONU3之间的光纤链路出现故障， 需要采用 OTDR技术进行断 点检测， 以便及时检测出故障所在的位置， 进行维护。
图 2为现有吉比特无源光网络断点检测系统结构示意图。 参见图 2, 该系统包括： OTDR、分光器（ Splitter )以及光网络单元（ ODU, Optical Net Unit ) , 其中， 相对于图 1 所示的吉比特无源光网络系统， 在进行光时域 的断点检测时， 需要断开 OLT与光纤之间的连接， 将 OTDR接入到 GPON 系统中， 即以 OTDR替代 OLT, 并通过光纤与 spliter相连接。 OTDR通过 发射接口发射光脉沖， 输出到到光纤内， 通过 Splitter向 ONU传输。
当光脉沖在光纤内传输时， 会由于光纤本身的性质以及连接器、 接合 点、 弯曲或其它类似的事件而产生散射、 反射， 其中一部分的散射光和反 射光通过光纤返回到 OTDR中，返回的有用信息由 OTDR中的探测器来测 量， 并作为光纤内不同位置上的时间或曲线片断， 通过时间或曲线片断的 分析， 可以确定断点的具体位置。 也就是说， OTDR使用瑞利散射和菲涅 尔反射来表征光纤的特性， 其中， 瑞利散射是由于光信号沿着光纤产生无 规律的散射而形成， 这些背向散射信号表明了由光纤而导致的衰减（损耗 / 距离）程度， 因而， 通过测量返回到 OTDR接收接口的一部分散射光， 可 以获取光纤的衰减（损耗 /距离）程度； 菲涅尔反射是离散的反射， 它是由 整条光纤中的个别点引起的， 这些点是由造成反向系数改变的因素， 在这 些点上， 会有很强的背向散射光被反射回来。 因此， OTDR通过利用瑞利 散射以及菲涅尔反射的信息， 可定位连接点， 光纤终端或断点。
由上述可见， 现有基于光时域检测仪进行光纤断点检测的 GPON断点 检测系统， 在进行断点检测的过程中， 需要先断开现有的 GPON系统， 然 后将 OTDR接入断点检测系统， 通过 OTDR发射光脉沖进入光纤， 利用光 脉沖的瑞利散射以及菲涅尔反射的信息进行检测，断点检测流程较为复杂； 进一步地， 在检测期间， 需要断开 OLT, 从而影响到其它没有断点处的网 络信号的正常传输。 例如， 上述例子中， 当 spilter到 ONU3之间的光纤发 生了光纤断裂，在检测期间，需要将 OLT从网络中断开，从而造成了 ONU 1、 ONU2的信号收发中断， 影响 GPON系统的正常运行； 而且， 在 GPON系 统经常发生故障的情况下， 需要频繁进行断开 OLT与插接 OLT的操作， 频繁的插接， 使得 OLT的工作可靠性降低。
综上所述， 现有技术的 GPON断点检测系统， 在进行断点检测过程中， 检测流程较为复杂， 且会影响到其它没有断点处的网络信号的正常传输。 发明内容
本发明的实施例提供了一种 OTDR光模块， 筒化断点检测流程、 保障系 统网络信号的正常传输。
本发明的实施例还提供了一种 GPON断点检测系统，筒化断点检测流程、 保障系统网络信号的正常传输。
根据本发明的一个方面， 提供了一种 OTDR光模块， 包括： 光路组件、 激光发射器、 激光探测器、 断点检测模块以及电信号采样电路， 其中，
光路组件，用于通过内置的上行光纤接口与外部光线路终端 OLT相连 的光纤相连， 通过内置的下行光纤接口与外部分光器相连的光纤相连， 通 过内置的激光发射接口与激光发射器相连， 通过内置的激光接收接口与激 光探测器相连；
激光发射器， 用于在进行断点检测时， 生成用于检测断点的第三波长 的光信号， 输出至光路组件的激光发射接口；
激光探测器， 用于接收从光路组件的激光接收接口输出的第三波长的 光信号， 将接收的第三波长的光信号转换为相应的电信号输出；
电信号采样电路， 用于与激光探测器相连， 对激光探测器输出的电信 号进行采样， 得到数字信号， 并发送给断点检测模块；
断点检测模块， 用于接收电信号采样电路发送的数字信号， 进行分析， 将分析结果与预先得到的无断点时采样进行分析得到的结果进行比较， 获 取断点或故障点位置。
较佳地，
所述光路组件通过上行光纤接口接收外部 OLT通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至外部分光器； 通过下行光 纤接口接收外部光网络单元 ONU通过光纤输出的第二波长的光信号，通过上 行光纤接口透射至光纤并传输至所述 OLT;
通过激光发射接口接收激光发射器发射的第三波长的光信号， 输出至下 行光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波 长的光信号， 输出至激光接收接口， 并由激光接收接口输出至激光探测器。 较佳地， 所述电信号采样电路在接收到激光探测器输出的电信号后， 进 一步用于对接收的电信号进行放大及滤波处理。
较佳地， 所述光路组件包括： 波分复用器以及环形器， 其中，
WDM , 通过内置的上行光纤接口接收 OLT通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至分光器； 通过下行光纤 接口接收 ONU通过光纤输出的第二波长的光信号， 通过上行光纤接口透 射至光纤并传输至 OLT;
通过内置的反射接口接收环形器输出的第三波长的光信号， 输出至下行 光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波长 的光信号， 输出至反射接口， 并由反射接口输出至环形器；
环形器， 用于通过内置的第一接口接收激光发射器发射的第三波长的光 信号， 通过内置的第二接口输出至 WDM 的反射接口； 通过第二接口接收 WDM的反射接口输出的反射的第三波长的光信号，并通过内置的激光接收接 口输出至激光探测器。
较佳地， 所述光路组件进一步包括设置于环形器的激光接收接口与激光 探测器之间的滤光片， 所述滤光片用于增透从环形器的激光接收接口输出的 第三波长的光信号。
较佳地， 所述激光发射器包括： 激光发射单元以及驱动电路单元， 其中， 驱动电路单元， 用于在启动进行断点检测时， 驱动激光发射单元发射第 三波长的激光， 输出至环形器的第一接口。
较佳地， 所述激光发射器进一步包括：
控制单元， 用于在接收到外部设备的断点检测指令后， 生成断点检测电 信号， 并输出至驱动电路单元， 以使驱动电路单元根据接收的断点检测电信 号， 驱动激光发射单元发射第三波长的激光。
较佳地， 所述激光发射单元为 1625nm的分布反馈式激光器发射光源。 较佳地， 所述激光探测器包括： 光电二极管以及跨阻放大器 TIA, 其中， 光电二极管， 用于接收从激光接收接口输出的光信号后， 向 TIA输出相 应的响应电流；
TIA, 用于接收响应电流， 根据接收的响应电流向电信号采样电路输出相 应的差分电信号。
较佳地， 所述光电二极管为雪崩光电二极管。 较佳地， 所述电信号采样电路包括：
模拟数字转换 ADC电路， 用于对激光探测器输出的电信号进行采样， 并 将采样得到的数字信号发送给断点检测模块进行存储。
较佳地， 所述电信号采样电路进一步包括放大电路， 放大电路置于激光 探测器与 ADC电路之间， 对激光探测器输出的电信号进行放大。
较佳地， 所述断点检测模块包括： 检测信号存储单元、 比较单元、 正常 运行信号存储单元以及断点位置确定单元， 其中，
检测信号存储单元， 用于存储 ADC电路在检测状态时输出的数字信号； 正常运行信号存储单元， 用于存储吉比特无源光网络断点检测系统在正 常运行状态时得到的数字信号；
比较单元， 用于比较检测信号存储单元存储的数字信号以及正常运行信 号存储单元存储的数字信号， 输出比较结果；
断点位置确定单元， 用于对比较单元输出的比较结果进行分析， 获取断 点或故障点的位置。
较佳地， 所述断点检测模块为现场可编程门阵列、 可编程阵列逻辑、 单 片机、 处理器或微控器。
一种吉比特无源光网络断点检测系统， 该系统包括： 光线路终端 OLT、 分光器以及光网络单元 ONU, 其中， 所述 OLT发射第一波长的光信号， 并接 收所述 ONU发射的第二波长的光信号；所述吉比特无源光网络断点检测系统 还包括： 光时域检测仪光模块，
OLT与光时域检测仪光模块相连， 光时域检测仪光模块与分光器相连； 光时域检测仪光模块， 用于接收 OLT输出的第一波长的光信号， 透射至 分光器； 接收 ONU输出的第二波长的光信号， 透射至 OLT; 生成第三波长的 光信号， 进行输出， 接收瑞利散射和菲涅尔反射返回的第三波长的光信号， 进行信号处理， 根据信号处理结果获取断点信息。
较佳地， 所述光时域检测仪光模块包括： 光路组件、 激光发射器、 激光 探测器、 断点检测模块以及电信号采样电路， 其中，
光路组件， 用于通过内置的上行光纤接口与 OLT相连的光纤相连， 通 过内置的下行光纤接口与分光器相连的光纤相连， 通过内置的激光发射接 口与激光发射器相连， 通过内置的激光接收接口与激光探测器相连；
激光发射器， 用于在进行断点检测时， 生成用于检测断点的第三波长 的光信号， 输出至光路组件的激光发射接口； 激光探测器， 用于接收从光路组件的激光接收接口输出的第三波长的 光信号， 将接收的第三波长的光信号转换为相应的电信号输出；
电信号采样电路， 用于与激光探测器相连， 对激光探测器输出的电信 号进行采样， 得到数字信号， 并发送给断点检测模块；
断点检测模块， 用于接收电信号采样电路发送的数字信号， 进行分析， 将分析结果与预先得到的无断点时采样进行分析得到的结果进行比较， 获 取断点或故障点位置。
较佳地，
所述光路组件通过上行光纤接口接收 OLT通过光纤输出的第一波长的光 信号， 通过下行光纤接口透射至光纤并传输至分光器； 通过下行光纤接口接 收 ONU通过光纤输出的第二波长的光信号，通过上行光纤接口透射至光纤并 传输至所述 OLT;
通过激光发射接口接收激光发射器发射的第三波长的光信号， 输出至下 行光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波 长的光信号， 输出至激光接收接口， 并由激光接收接口输出至激光探测器。
较佳地， 所述光路组件包括： 波分复用器以及环形器， 其中，
WDM, 通过内置的上行光纤接口接收 OLT通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至分光器； 通过下行光纤 接口接收 ONU通过光纤输出的第二波长的光信号， 通过上行光纤接口透 射至光纤并传输至 OLT;
通过内置的反射接口接收环形器输出的第三波长的光信号， 输出至下行 光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波长 的光信号， 输出至反射接口， 并由反射接口输出至环形器；
环形器， 用于通过内置的第一接口接收激光发射器发射的第三波长的光 信号， 通过内置的第二接口输出至 WDM 的反射接口； 通过第二接口接收 WDM的反射接口输出的反射的第三波长的光信号，并通过内置的激光接收接 口输出至激光探测器。
较佳地， 所述光路组件进一步包括设置于环形器的激光接收接口与激光 探测器之间的滤光片， 所述滤光片用于增透从环形器的激光接收接口输出的 第三波长的光信号。
较佳地， 所述激光发射器包括： 激光发射单元以及驱动电路单元， 其中， 驱动电路单元， 用于在启动进行断点检测时， 驱动激光发射单元发射第 三波长的激光， 输出至环形器的第一接口。
较佳地， 所述激光发射器进一步包括：
控制单元， 用于在接收到外部设备的断点检测指令后， 生成断点检测电 信号， 并输出至驱动电路单元， 以使驱动电路单元根据接收的断点检测电信 号， 驱动激光发射单元发射第三波长的激光。
较佳地， 所述激光探测器包括： 光电二极管以及跨阻放大器 TIA, 其中， 光电二极管， 用于接收从激光接收接口输出的光信号后， 向 TIA输出相 应的响应电流；
TIA, 用于接收响应电流， 根据接收的响应电流向电信号采样电路输出相 应的差分电信号。
较佳地， 所述电信号采样电路包括：
模拟数字转换 ADC电路， 用于对激光探测器输出的电信号进行采样， 并 将采样得到的数字信号发送给断点检测模块进行存储；
放大电路， 放大电路置于激光探测器与 ADC电路之间， 对激光探测器输 出的电信号进行放大。
较佳地， 所述断点检测模块包括： 检测信号存储单元、 比较单元、 正常 运行信号存储单元以及断点位置确定单元， 其中，
检测信号存储单元， 用于存储 ADC电路在检测状态时输出的数字信号； 正常运行信号存储单元， 用于存储吉比特无源光网络断点检测系统在正 常运行状态时得到的数字信号；
比较单元， 用于比较检测信号存储单元存储的数字信号以及正常运行信 号存储单元存储的数字信号， 输出比较结果；
断点位置确定单元， 用于对比较单元输出的比较结果进行分析， 获取断 点或故障点的位置。
由上述可见， 本发明实施例的 OTDR光模块及 GPON断点检测系统， 该 系统包括： 光线路终端 OLT、 分光器、 光网络单元 ONU以及光时域检测仪光 模块， OLT与光时域检测仪光模块相连， 光时域检测仪光模块与分光器相连； 光时域检测仪光模块， 用于接收 OLT输出的第一波长的光信号， 透射至分光 器； 接收 ONU输出的第二波长的光信号， 透射至 OLT; 生成第三波长的光信 号， 进行输出， 接收瑞利散射和菲涅尔反射返回的第三波长的光信号， 进行 信号处理， 根据信号处理结果获取断点信息。 这样， 在进行断点检测时， 无 需断开 OLT, 从而不会影响 GPON中正常的业务通信， 在保障系统网络信号 正常传输的基础上， 筒化了断点检测流程； 进一步地， 由于无需频繁进行断 开 OLT与插接 OLT的操作， 减少了 OLT频繁的插接， 提高了 OLT的工作可 靠性。
附图说明
图 1为现有吉比特无源光网络系统结构示意图。
图 2为现有吉比特无源光网络断点检测系统结构示意图。
图 3为本发明实施例吉比特无源光网络断点检测系统结构示意图。
图 4为本发明实施例光时域检测仪光模块的结构示意图。
图 5为本发明实施例吉比特无源光网络断点检测系统进行检测的示意图。 图 6为存储到断点检测模块中的数字信号波形示意图。
图 7为基于图 6计算得到的数字信号波形与距离的示意图。
具体实施方式
为使本发明的目的、 技术方案及优点更加清楚明白， 以下参照附图并举 出优选实施例， 对本发明进一步详细说明。 然而， 需要说明的是， 说明书中 列出的许多细节仅仅是为了使读者对本发明的一个或多个方面有一个透彻的
"本申请使用的 "模块"、、 "系统: 等 语旨在包括与计算机相关的实体， 例如但不限于硬件、 固件、 软硬件组合、 软件或者执行中的软件。 例如， 模 块可以是， 但并不仅限于： 处理器上运行的进程、 处理器、 对象、 可执行程 序、 执行的线程、 程序和 /或计算机。 举例来说， 计算设备上运行的应用程序 和此计算设备都可以是模块。 一个或多个模块可以位于执行中的一个进程和 / 或线程内， 一个模块也可以位于一台计算机上和 /或分布于两台或更多台计算 机之间。
现有的 GPON断点检测系统， 在进行断点检测的过程中， 需要先断开 OLT, 然后将 OTDR接入断点检测系统进行断点检测， 在检测完毕后， 再 断开 OTDR, 并将 OLT接入系统进行正常通信， 使得断点检测流程较为复 杂， 并影响到网络信号的正常传输。
本发明实施例中， 提出一种在线的 OTDR光模块， 在不断开 OLT的 情况下进行断点检测， 通过将该 OTDR光模块串联接入吉比特无源光网络 系统， 对 OLT输出的下行链路光信号以及传输至 OLT的上行链路光信号 进行透传， 通过发射光信号， 并接收 OTDR光模块发射的光信号由于散射 和反射返回的 OTDR探测光，进行断点分析，将断点分析结果反馈给系统， 并且具有价格低廉， 操作筒单， 支持热插拔， 易更换、 维护等优点。
图 3为本发明实施例吉比特无源光网络断点检测系统结构示意图。 参 见图 3 , 该系统包括： 光线路终端 （OLT ) 301、 分光器（spliter ) 302、 光 时域检测仪光模块 303以及光网络单元 （ ONU ) 304, 其中， OLT301、 分 光器 302以及光网络单元 ONU304,分别与现有技术的 PON系统中的 OLT、 spliter和 ONU相同；
OLT301 与光时域检测仪光模块 303相连， 光时域检测仪光模块 303 与分光器 302相连， 分光器 302与一个或多个 ONU304相连， 即光时域检 测仪光模块 303 串联接于 OLT301与 spliter302之间。 具体来说， OLT301 通过光纤与光时域检测仪光模块 303相连， 光时域检测仪光模块 303通过 光纤与分光器 302相连，分光器 302通过光纤与一个或多个 ONU304相连。
较佳地， 光时域检测仪光模块 303在吉比特无源光网络断点检测系统 中的位置更靠近 OLT301处。
OLT301 , 用于发射第一波长的光信号（下行通信光信号） ， 经光纤进 入光时域检测仪光模块 303 ,由光时域检测仪光模块 303透射至分光器 302; 通过光纤接收光时域检测仪光模块 303透射的第二波长的光信号 （上行通 信光信号） ， 进行处理；
本发明实施例中， OLT301 将发射的第一波长的光信号通过光纤传输 至光时域检测仪光模块 303的上行光纤接口，并经光时域检测仪光模块 303 的下行光纤接口进入光纤， 在光纤中传输后， 到达分光器 302; 通过光纤 接收光时域检测仪光模块 303的上行光纤接口透射的第二波长的光信号， 进行处理。
本发明实施例中， OLT301 对于光信号的具体处理流程， 与现有技术 相同， 具体可参见相关技术文献， 在此不再赘述。
光时域检测仪光模块 303 , 用于接收 OLT301输出的第一波长的光信 号， 透射至分光器 302; 接收 ONU304输出的第二波长的光信号， 透射至 OLT301 ; 生成第三波长的光信号， 进行输出， 接收瑞利散射和菲涅尔反射 返回的第三波长的光信号， 进行信号处理， 根据信号处理结果获取断点信 本发明实施例中，光时域检测仪光模块 303对接收的光信号进行判断， 以确定是否为第一波长的光信号、第二波长的光信号或第三波长的光信号， 具体可参见相关技术文献， 在此不再赘述。
通过瑞利散射和菲涅尔反射返回的第三波长的光信号， 可以是光时域 检测仪光模块 303与分光器 302之间的通信链路上通过瑞利散射和菲涅尔 反射返回的光信号， 也可以是分光器 302上通过瑞利散射和菲涅尔反射返 回的光信号， 也可以是分光器 302与 ONU304之间的通信链路上通过瑞利 散射和菲涅尔反射返回的光信号， 还可以是 ONU304上通过瑞利散射和菲 涅尔反射返回的光信号。
分光器 302, 用于接收光时域检测仪光模块 303输出的光信号， 进行 分光处理， 分别输出至与自身相连的一个或多个 ONU304; 接收 ONU304 生成的第二波长的光信号， 进行合流处理， 输出至光时域检测仪光模块 303；接收通过瑞利散射和菲涅尔反射的第三波长的光信号，进行汇流处理， 输出至光时域检测仪光模块 303;
本发明实施例中， 分光器 302用于对发送至 ONU304的下行光信号进 行分光处理， 以及， 对接收的上行光信号进行汇流处理， 输出至光时域检 测仪光模块 303。
ONU304, 用于通过光纤接收第一波长的光信号， 进行处理后， 生成 第二波长的光信号， 输出至分光器 302; 接收第三波长的光信号， 将通过 瑞利散射和菲涅尔反射的第三波长的光信号通过光纤输出至分光器 302。
本发明实施例中， ONU304通过光纤接收第一波长的光信号， 进行处 理后， 生成第二波长的光信号的详细流程， 属于现有技术， 具体可参见相 关技术文献。
如果 ONU304通过光纤接收到第三波长的光信号， 表明光时域检测仪 光模块 303与 ONU304之间的通信链路正常；如果光时域检测仪光模块 303 输出第三波长的光信号， 而 ONU304没有接收到第三波长的光信号， 表明 光时域检测仪光模块 303与 ONU304之间的通信链路发生了异常。
本发明实施例中， OLT301发射第一波长的光信号（下行通信光信号）， 进入 OLT301与光时域检测仪光模块 303之间的光纤， 在光纤中传输后， 到达光时域检测仪光模块 303的上行光纤接口，经光时域检测仪光模块 303 的透射后， 从光时域检测仪光模块 303的下行光纤接口进入光时域检测仪 光模块 303与分光器 302之间的光纤， 在光纤中传输后， 进入分光器 302, 经分光器 302的分光处理后， 进入分光器 302与 ONU304之间的光纤， 最 后到达 ONU304; ONU304对接收的第一波长的光信号进行处理后， 发射 第二波长的光信号 （上行通信光信号） ， 通过分光器 302、 分光器 302与 光时域检测仪光模块 303之间的光纤， 进入光时域检测仪光模块 303的下 行光纤接口， 经光时域检测仪光模块 303的透射后， 从光时域检测仪光模 块 303的上行光纤接口进入光纤，在光纤中传输后，到达 OLT301 , OLT301 接收第二波长的光信号进行处理， 根据光信号处理结果发射第一波长的光 信号 （下行通信光信号） ， 如此循环， 直至流程结束；
光时域检测仪光模块 303在进行断点检测时， 通过其下行光纤接口发 射第三波长的光信号， 并依序经过光时域检测仪光模块 303与分光器 302 之间的光纤、分光器 302、分光器 302与 ONU304之间的光纤以及 ONU304 的链路进行光信号传输， 如果上述链路中发生了断点， 则从断点反射第三 波长的光信号， 并逆向经过上述链路， 到达光时域检测仪光模块 303的下 行光纤接口， 光时域检测仪光模块 303的下行光纤接口接收反射的第三波 长的光信号， 将反射的第三波长的光信号转换为电信号后进行采样， 模数 转换， 得到数字信号， 将采样得到的数字信号进行存储、 分析， 从而判断 出断点或故障点位置。
实际应用中， 光时域检测仪光模块 303 启动进行断点检测， 可以是 OLT301 在发射第一波长的光信号后， 如果在预先设置的时间内没有接收 到响应于第一波长的光信号的第二波长的光信号， 通过向光时域检测仪光 模块 303发送触发信息，触发启动光时域检测仪光模块 303进行断点检测， 也可以是光时域检测仪光模块 303定时发射第三波长的光信号， 根据反射 的第三波长的光信号进行断点故障检测。 当然， 还可以是通过其它方式触 发启动进行断点检测。
关于在光时域检测仪光模块 303中设置各类检测参数， 例如， 光纤折 射率 n、 光脉沖波长等， 具体可参见相关技术文献， 在此不再赘述。
较佳地， 光时域检测仪光模块 303根据光纤不同位置的背向散射光反 馈的信息进行分析后，在液晶显示屏上形成波形， 并通过该波形进行分析， 从而获知光纤发生故障的位置。
所应说明的是， 光时域检测仪光模块 303发射的光信号的第三波长只 要不与第一波长的光信号以及第二波长的光信号（上下行光波）相同即可， 例如，常用的 10G下行光波长为 1577 nm,2.5G上行光波长为 1270nm; 2.5G 下行光波长为 1490 nm, 1G上行光波长为 1310nm。 为了不影响正常业务， 选择用于 OTDR断点检测的光波长为 1625nm。 本发明实施例中， 透射是指光时域检测仪光模块 303作为转发器， 对 接收的光信号不作任何处理， 转发至下一接收单元。
由上述可以看出， 串接于 OLT301与分光器 302之间的光时域检测仪 光模块 303 , 可以透射 GPON系统中的通信信号， 例如， 第一波长的下行 通信的光信号和第二波长的上行通信的光信号，从而在断点检测的流程中， 实现通信数据的传输， 使得光时域检测仪光模块 303的存在， 不会影响现 有 GPON系统的通信。
图 4为本发明实施例光时域检测仪光模块的结构示意图。 参见图 4, 该光模块包括： 光路组件 401、 激光发射器 402、 激光探测器 403、 断点检 测模块 405、 电信号采样电路 404, 其中，
光路组件 401 , 用于通过内置的上行光纤接口与 OLT301相连的光纤 相连， 通过内置的下行光纤接口与分光器 302相连的光纤相连， 通过内置 的激光发射接口与激光发射器 402相连， 通过内置的激光接收接口与激光 探测器 403相连；
具体来说， 光路组件 401 , 通过上行光纤接口接收 OLT301通过光纤 输出的第一波长的光信号， 通过下行光纤接口透射至光纤并传输至分光器 302; 通过下行光纤接口接收 ONU304通过光纤输出的第二波长的光信号， 通过上行光纤接口透射至光纤并传输至 OLT301 ;
通过激光发射接口接收激光发射器 402发射的第三波长的光信号， 输 出至下行光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射 的第三波长的光信号， 输出至激光接收接口， 并由激光接收接口输出至激 光探测器 403。
本发明实施例中， 光路组件 401包含四个接口， 分别为： 上行光纤接 口、 下行光纤接口、 激光发射接口以及激光接收接口， 其中， 上行光纤接 口与下行光纤接口分别与光纤相连， 即上行光纤接口通过光纤与 OLT301 相连， 下行光纤接口通过光纤与分光器 302相连； 光路组件 401通过激光 发射接口接收激光发射器 402发射的第三波长的光信号， 进行耦合后将激 光发射器 402发射的第三波长的光信号从下行光纤接口输出到光纤进行传 输。
本发明实施例中， 第三波长的光信号在 GPON系统的光纤中传输， 在 光纤的断裂点或设备（例如， 分光器以及 ONU )的故障处或者其它故障地 方被反射,被反射的第三波长的光信号在光纤中传输，返回到光路组件 401 后， 光路组件 401从下行光纤接口接收反射的第三波长的光信号， 经分光 处理后， 将反射的第三波长的光信号通过激光接收接口输出到激光探测器 403。
激光发射器 402, 用于在进行断点检测时， 生成用于检测断点的第三 波长的光信号， 输出至光路组件 401的激光发射接口；
本发明实施例中， 激光发射器 402在进行断点检测时， 可以是将固定 周期的脉沖电信号进行电光转换， 生成第三波长的光信号并发射。
激光探测器 403 , 用于接收从光路组件 401 的激光接收接口输出的第 三波长的光信号， 将接收的第三波长的光信号转换为相应的电信号输出； 本发明实施例中， 激光探测器 403接收的第三波长的光信号为反射信 号， 该反射信号可以反映出网络光纤中的断点位置， 在将反射的光信号转 换为电信号并进行采样后， 对采样的数字信号进行分析即可判断出断点或 故障点位置。
电信号采样电路 404, 用于与激光探测器 403相连，对激光探测器 403 输出的电信号进行采样， 得到数字信号， 并发送给断点检测模块 405; 本发明实施例中， 电信号采样电路 404还可以对激光探测器 403输出 的电信号进行放大及滤波处理， 并对放大及滤波处理后的电信号再进行采 样， 输出采样的数字信号。
断点检测模块 405 , 用于接收电信号采样电路 404发送的数字信号， 进行分析， 将分析结果与预先得到的无断点时采样进行分析得到的结果进 行比较， 获取断点或故障点位置。
本发明实施例中， 断点检测模块 405还可以用于将接收的电信号采样 电路 404发送的数字信号进行存储。
断点检测模块 405根据从电信号采样电路 404接收并存储的数字信号， 生成第一波形， 与预先存储的根据无断点时采样得到的数字信号生成的第 二波形进行比对， 根据比对结果判断出断点或故障点位置。 当然， 实际应 用中， 也可以根据接收的数字信号与预先存储的数字信号进行比对， 预先 存储的数字信号是在正常情况下， 即无断点、 无故障点的情况下， 对反射 的第三波长的光信号进行采样及模数转换后得到的采样数字信号。
光时域检测仪光模块 303的外接引脚具体可以包括：
SDA引脚， 即串口通信线数据引脚；
SCL引脚， 即串口通信线时钟引脚； GND和 VCC引脚。
具体地， SDA引脚和 SCL引脚与断点检测模块 405相连， 控制单元 1202通过 SDA引脚和 SCL引脚与外部设备进行通信。
光时域检测仪光模块 303的外接引脚的电接口可以采用插针式的 4pin 结构。
本发明实施例中， 将分析结果与预先得到的无断点时采样进行分析得 到的结果进行比较， 获取断点或故障点位置为现有技术， 具体可参见相关 技术文献， 在此不再赞述。 此处仅筒单介绍一下原理。
图 5为本发明实施例吉比特无源光网络断点检测系统进行检测的示意 图。 参见图 5 , 假设光时域检测仪光模块与分光器之间， 有一段长 10km的 光纤， 分光器与 ONU1之间的距离为 1km, 分光器与 ONU2之间的距离为 2km, 分光器与 ONU3之间的距离为 10km, 但是在 7km处发生了光纤断 裂。
在进行断点检测时 （通信业务可以正常执行） ， 光时域检测仪光模块 的激光发射器 402发射 1625nm波长的光信号， 输出至光路组件 401的激 光发射接口， 激光发射接口将接收的 1625nm波长的光信号输出至下行光 纤接口， 并由下行光纤接口输出至分光器， 由分光器进行分光处理后， 分 别输出， 当 1625nm波长的光信号传输至分光器与 ONU3之间距离为 7km 处， 光纤断裂， 断裂处反射 1625nm波长的光信号， 经光纤反射回分光器， 分光器经回流处理后， 传输至光时域检测仪光模块， 光时域检测仪光模块 的下行光纤接口接收光信号， 并确定接收的光信号为 1625nm波长的光信 号， 输出至激光接收接口， 并由激光接收接口输出至激光探测器 403; 激光探测器 403将接收的光信号转换为电信号， 并经电信号采样电路 404采样为数字信号， 存储到断点检测模块 405中。
图 6为存储到断点检测模块中的数字信号波形示意图。 参见图 6, 横 坐标为时间， 纵坐标为接收光功率 （dbm ) , 假设自光时域检测仪光模块 发光之后， 分别在 T1 - T4时间点接收到各光信号的反射峰， 则各反射光 处距离光线路终端光模块的距离根据如下公式计算得到：
式中，
c = 3xl08m/ s , 为光速；
«为光纤纤芯的折射率； d为计算出来的数值， 即反射光处距离光线路终端光模块的距离。 图 7为基于图 6计算得到的数字信号波形与距离的示意图。 参见图 7, 横坐标为反射光处距离光线路终端光模块的距离， 纵坐标为接收光功率 ( dbm ) , 从图 7所示的信号波形可以看出， 在距离光时域检测仪光模块 10km处， 由于分光器的反射， 探测到一个菲尼尔反射峰， 在距离光时域检 测仪光模块 11km处， 探测到 ONU1的反射峰， 在距离光时域检测仪光模 块 12km处， 探测到 ONU2的反射峰， 在距离光时域检测仪光模块 17km 处， 探测到反射光处 （光纤断裂处） 的反射峰。
对比系统布局， 即正常情况的信号波形， 也就是预先得到的无断点时 采样进行分析得到的结果： 在距离光时域检测仪光模块 10km处， 由于分 光器的反射， 探测到一个反射峰， 在距离光时域检测仪光模块 11km处， 由于 ONU1的反射， 探测到 ONU1的反射峰， 在距离光时域检测仪光模块 12km处， 由于 ONU2的反射， 探测到 ONU2的反射峰， 在距离光时域检 测仪光模块 20km处， 由于 ONU3的反射， 探测到 ONU3的反射峰。
由此， 可以判定， 由于图 7所示的信号波形中， 未包含 ONU3的反射 峰， 因而， 确定分光器到 ONU3之间的链路出现了断点， 该断点距离光时 域检测仪光模块 17km。
其中，
光路组件 401 包括： 波分复用器 （ WDM , Wavelength Division Multiplex ) 411以及环形器 412, 其中，
WDM411 具有三个接口， 分别为公共接口 （COM接口） 、 透射接口 ( Pass接口 ) 以及反射接口 （ Reflect接口 ） 。 其中， WDM411的 COM接 口作为光路组件 401 的下行光纤接口接入光纤， WDM411 的 Pass接口作 为光路组件 401的上行光纤接口接入光纤， WDM411的 Reflect接口与环 形器 412相连；
WDM411 , 通过上行光纤接口接收 OLT301通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至分光器 302; 通过下行 光纤接口接收 ONU304通过光纤输出的第二波长的光信号， 通过上行光纤 接口透射至光纤并传输至 OLT301 ;
通过 Reflect接口接收环形器 412输出的第三波长的光信号，输出至下 行光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三 波长的光信号， 输出至 Reflect接口， 并由 Reflect接口输出至环形器 412; 本发明实施例中， 为了将 1490nm 的下行光、 1310nm 的上行光以及 1625nm的光波进行光路耦合， 引入 WDM来实现这种功能。 WDM411的 下行光纤接口接收第二波长的光信号以及第三波长的光信号， 进行波分复 用的详细处理流程， 具体可参见相关技术文献， 在此不再赘述。
环形器 412具有三个接口， 分别为第一接口、 第二接口、 第三接口； 环形器 412的第二接口与 WDM411的 Reflect接口相连； 例如， 环形 器 412的第二接口与 WDM411的 Reflect接口可以通过光纤相连， 或者， 两个接口直接相连通。
环形器 412的第一接口与第三接口， 分别作为光路组件 401的激光发 射接口和激光接收接口；
环形器 412, 用于通过激光发射接口接收激光发射器 402发射的第三 波长的光信号， 通过第二接口输出至 WDM411的 Reflect接口； 通过第二 接口接收 WDM411的 Reflect接口输出的反射的第三波长的光信号， 并通 过激光接收接口输出至激光探测器 403。
本发明实施例中， 环形器 412用于将发射光与反射光进行分离， 即由 激光发射器 402发出的 1625nm的激光， 由第一接口输入， 由第二接口输 出； 由第二接口输入的 1625nm的探测光（反射光） ， 由第三接口输出， 输送给激光探测器 403。
激光发射器 402发射的第三波长的光信号经环形器 412的第一接口（第 一接口）进入光路组件 401的环形器 412, 从环形器 412的第二接口射出； 从光纤中反射回来的第三波长的光信号， 经 WDM411的 COM接口进入光 路组件 401 , 并从 WDM411的 Reflect接口输出到环形器 412 , 环形器 412 的第二接口接收从 WDM411的 Reflect接口射入的反射的第三波长的光信 号后， 经环形器 412的第三接口进入光纤， 传输至激光探测器 403。
较佳地， 由于反射光的光强很小， 为了避免系统级杂散波长对 OTDR 灵敏度的影响， 光路组件 401中还可包括设置于环形器 412的第三接口与 激光探测器 403之间的滤光片 413 , 通过在激光探测器 403之前增加滤光 片， 增透 1625nm的光波长， 而对 1610nm以下的光波长起阻挡作用。
本发明实施例中， 滤光片 413为第三波长光信号的增透片， 用于增透 从环形器 412的第三接口输出的第三波长的光信号， 并且隔萬系统中的杂 散波长。
实际应用中， 为了实现上述的功能， WDM411的 COM接口为可以传 输全波段光信号的接口， 其 Pass接口为可以透射第一、 二波长光信号的接 口， 其 Reflect接口为反射第三波长光信号的接口。 例如， 上述的第一波长 具体为 1490nm; 第二波长为 1310nm; 第三波长为 1625nm, 则 Pass接口 设计为透射 1580nm 以下波长光信号的接口， Reflect 接口设计为反射 1610nm以上的波长光信号的接口。 WDM411的具体指标如下表 1所示： 表 1
Figure imgf000019_0001
表 1中， Pass -〉 Com表示光波从 PASS口进， COM口出； 双向都可以 通过表示光波既可以从 PASS口进， COM口出，也可以从 COM口进， PASS 口出。
其中， 插入损耗要求尽量的小， 以最低限度减少系统的损耗； 隔离度 要求尽量的高， 以减少串扰、 提高系统的灵敏度。
激光发射器 402包括：激光发射单元以及驱动电路单元（图中未示出）， 其中，
驱动电路单元， 用于在启动进行断点检测时， 驱动激光发射单元发射 第三波长的激光， 输出至环形器的第一接口。
本发明实施例中， 激光发射单元具体可以是 1625nm的分布反馈式激 光器 （DFB , Distribute FeedBack Laser )发射光源， 将光脉沖信号转化为 突发发射光信号。
实际应用中， 激光发射器 402还可以包括：
控制单元， 用于在接收到外部设备的断点检测指令后， 生成断点检测 电信号， 并输出至驱动电路单元， 以使驱动电路单元根据接收的断点检测 电信号， 驱动激光发射单元发射第三波长的激光。
激光探测器 403 包括： 光电二极管以及跨阻放大器 （ TIA , Tranimpedance Amplifier ) (图中未示出） ， 其中，
光电二极管， 用于接收从激光接收接口输出的光信号后， 向 ΤΙΑ输出 相应的响应电流;
ΤΙΑ, 用于接收响应电流， 根据接收的响应电流向电信号采样电路 404 输出相应的差分电信号。
本发明实施例中， 光电二极管具体可以是光模块中的雪崩光电二极管 ( APD, Avalanche Photo Diode ) 。
电信号采样电路 404 包括： 模拟数字转换 （ADC, Analog to Digital Converter ) 电路,
ADC电路， 用于对激光探测器 403输出的电信号进行采样， 并将采样 得到的数字信号发送给断点检测模块 405进行存储。
本发明实施例中，较佳地， 电信号采样电路 404还可以包括放大电路， 放大电路置于激光探测器 403与 ADC电路之间， 对激光探测器 403输出 的电信号进行放大， 以使 ADC电路对放大电路放大后的电信号进行采样， 将采样得到的数字信号发送给断点检测模块 405进行存储。
断点检测模块 405包括： 检测信号存储单元、 比较单元、 正常运行信 号存储单元以及断点位置确定单元 （图中未示出） ， 其中，
检测信号存储单元， 用于存储 ADC 电路在检测状态时输出的数字信 正常运行信号存储单元， 用于存储吉比特无源光网络断点检测系统在 正常运行状态时得到的数字信号；
比较单元， 用于比较检测信号存储单元存储的数字信号以及正常运行 信号存储单元存储的数字信号， 输出比较结果；
断点位置确定单元， 用于对比较单元输出的比较结果进行分析， 获取 断点或故障点的位置。
本发明实施例中， 断点位置确定单元还可以进一步用于将判断出的断 点或故障点的位置信息输出至预先设置的外部设备。
实际应用中， 断点检测模块 405具体可以是由逻辑阵列电路实现， 例 如， 现场可编程门阵列 （FPGA, Field Programmable Gata Array ) 、 可编程 阵列逻辑 （ PAL , Programmable Array Logic ) 等电路实现； 或者， 也可以 通过如单片机、 处理器、 微控器等计算芯片来实现。 即断点检测模块 405 可以为 FPGA、 PAL、 单片机、 处理器或微控器。 在进行断点检测时， FPGA安装在闪存 （Flash ) 中的程序， 发送用于 断点检测的脉沖信号 （图 4中虚线所示） 给驱动电路单元， 驱动电路单元 驱动激光发射单元， 将 FPGA发送来的电脉沖信号转化为 1625nm的光脉 沖信号； 系统中反射回的光信号经过 APD探测器的光电转化，将光信号转 化为电流信号， 进而经过跨阻抗放大器 （TIA, Transimpedance Amplifier ) 的转化和运放的处理， 输入给 ADC 电路， 将模拟信号转化成数字信号之 后输送给 FPGA, FPGA对接收的数字信号进行分析和计算， 确定断点位 置。
实际应用中， 光时域检测仪光模块 303的电接口可以采用联合测试行 动小组（ JTAG, Joint Test Action Group )接口的 lOpin结构， 其中 4pin分 别为用于 I2C数据的 SDA、 I2C时钟的 SCL、 用于接地线的 GND和用于提 供电源的 VCC, 另外 6pin为调试电路用，通过 JTAG接口与外部系统分析 设备通信， 系统通过 I2C总线通讯方式读取 FPGA的数据， 从而确定光纤 断点位置。
具体来说：
在 GPON系统中， 位于 GPON OLT中 1490nm的 DFB激光器作为下 行链路的光源使用， 发送连续 2.488Gbps 的信号， 位于 GPON OLT 中 1310nm的 APD探测器接收由 ONU发送来的上行突发光包， 进行数据接 收。
当将 OTDR光模块（光时域检测仪光模块）串入系统时，内置的 1625nm 的 DFB激光器发送一系列突发激光， 经过光纤链路中的断点时， 由于瑞利 散射和菲涅尔反射， 会有一部分回损光反射回光纤， 进而返回光时域检测 仪光模块中内置的 1625nm的 APD探测器。 1625nm的 APD探测器收到反 射回来的光， 经过光电转化， 形成电流信号， 然后经过运放处理和 ADC 采样， 作为数字信号传递给 FPGA。 FPGA将接收到的信号与 Flash存放的 正常情况下的信号进行比较， 找到发生断点的位置， 即相对于正常信号下 多出的信号峰值，该峰值对应的位置为断点的位置，通过 I2C总线读取 FPGA 的数据， 得知断点发生的位置。
由上述可见， 本发明实施例的吉比特无源光网络断点检测系统， 通过 将光时域检测仪光模块串联进吉比特无源光网络断点检测系统中的 OLT 与分光器之间， 而光时域检测仪光模块可以透射通信光信号 （第一波长的 光信号以及第二波长的光信号） ， 并且发射断点检测光信号 （第三波长的 光信号） ， 根据反射的第三波长的光信号进行断点检测， 确定断点位置。 使得在进行断点检测时， 无需断开现有 GPON系统中的 OLT, 从而不会影 响无源光网络中的正常通信信号， 筒化了断点检测流程， 保障了系统网络信 号的正常传输； 进一步， 光时域检测仪光模块在断点分析中， 可以省掉光 时域反射仪的设备， 电路成本较低， 与传统的光时域反射仪相比， 具有价 格低廉、 操作筒单、 易维护等优点， 从而以低成本实现了无源光网络系统 的断点检测； 而且， 由于无需频繁进行断开 OLT与插接 OLT的操作， 减少 了 0LT频繁的插接， 提高了 OLT的工作可靠性。
本领域普通技术人员可以理解实现上述实施例方法中的全部或部分步 骤是可以通过程序来指令相关的硬件来完成， 该程序可以存储于一计算机 可读取存储介质中， 如： ROM/RAM、 磁碟、 光盘等。
以上所述仅是本发明的优选实施方式， 应当指出， 对于本技术领域的普 通技术人员来说， 在不脱离本发明原理的前提下， 还可以作出若干改进和润 饰， 这些改进和润饰也应视为本发明的保护范围。

Claims

权 利 要 求 书
1. 一种光时域检测仪光模块， 其特征在于， 该光时域检测仪光模块包括: 光路组件、 激光发射器、 激光探测器、 断点检测模块以及电信号采样电路， 其中，
光路组件，用于通过内置的上行光纤接口与外部光线路终端 OLT相连 的光纤相连， 通过内置的下行光纤接口与外部分光器相连的光纤相连， 通 过内置的激光发射接口与激光发射器相连， 通过内置的激光接收接口与激 光探测器相连；
激光发射器， 用于在进行断点检测时， 生成用于检测断点的第三波长 的光信号， 输出至光路组件的激光发射接口；
激光探测器， 用于接收从光路组件的激光接收接口输出的第三波长的 光信号， 将接收的第三波长的光信号转换为相应的电信号输出；
电信号采样电路， 用于与激光探测器相连， 对激光探测器输出的电信 号进行采样， 得到数字信号， 并发送给断点检测模块；
断点检测模块， 用于接收电信号采样电路发送的数字信号， 进行分析， 将分析结果与预先得到的无断点时采样进行分析得到的结果进行比较， 获 取断点或故障点位置。
2. 如权利要求 1所述的光时域检测仪光模块， 其特征在于，
所述光路组件通过上行光纤接口接收外部 OLT通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至外部分光器； 通过下行光 纤接口接收外部光网络单元 ONU通过光纤输出的第二波长的光信号，通过上 行光纤接口透射至光纤并传输至所述 OLT;
通过激光发射接口接收激光发射器发射的第三波长的光信号， 输出至下 行光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波 长的光信号， 输出至激光接收接口， 并由激光接收接口输出至激光探测器。
3. 如权利要求 2所述的光时域检测仪光模块， 其特征在于， 所述电信号 采样电路在接收到激光探测器输出的电信号后， 进一步用于对接收的电信号 进行放大及滤波处理。
4. 如权利要求 1至 3任一项所述的光时域检测仪光模块， 其特征在于， 所述光路组件包括： 波分复用器以及环形器， 其中，
WDM, 通过内置的上行光纤接口接收 OLT通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至分光器； 通过下行光纤 接口接收 ONU通过光纤输出的第二波长的光信号， 通过上行光纤接口透 射至光纤并传输至 OLT;
通过内置的反射接口接收环形器输出的第三波长的光信号， 输出至下行 光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波长 的光信号， 输出至反射接口， 并由反射接口输出至环形器；
环形器， 用于通过内置的第一接口接收激光发射器发射的第三波长的光 信号， 通过内置的第二接口输出至 WDM 的反射接口； 通过第二接口接收 WDM的反射接口输出的反射的第三波长的光信号，并通过内置的激光接收接 口输出至激光探测器。
5. 如权利要求 4所述的光时域检测仪光模块， 其特征在于， 所述光路组 件进一步包括设置于环形器的激光接收接口与激光探测器之间的滤光片， 所 述滤光片用于增透从环形器的激光接收接口输出的第三波长的光信号。
6. 如权利要求 5所述的光时域检测仪光模块， 其特征在于， 所述激光发 射器包括： 激光发射单元以及驱动电路单元， 其中，
驱动电路单元， 用于在启动进行断点检测时， 驱动激光发射单元发射第 三波长的激光， 输出至环形器的第一接口。
7. 如权利要求 6所述的光时域检测仪光模块， 其特征在于， 所述激光发 射器进一步包括：
控制单元， 用于在接收到外部设备的断点检测指令后， 生成断点检测电 信号， 并输出至驱动电路单元， 以使驱动电路单元根据接收的断点检测电信 号， 驱动激光发射单元发射第三波长的激光。
8. 如权利要求 6所述的光时域检测仪光模块， 其特征在于， 所述激光发 射单元为 1625nm的分布反馈式激光器发射光源。
9. 如权利要求 8所述的光时域检测仪光模块， 其特征在于， 所述激光探 测器包括： 光电二极管以及跨阻放大器 TIA, 其中，
光电二极管， 用于接收从激光接收接口输出的光信号后， 向 TIA输出相 应的响应电流；
TIA, 用于接收响应电流， 根据接收的响应电流向电信号采样电路输出相 应的差分电信号。
10. 如权利要求 9所述的光时域检测仪光模块， 其特征在于， 所述光电 二极管为雪崩光电二极管。
11. 如权利要求 9所述的光时域检测仪光模块， 其特征在于， 所述电信 号采样电路包括：
模拟数字转换 ADC电路， 用于对激光探测器输出的电信号进行采样， 并 将采样得到的数字信号发送给断点检测模块进行存储。
12. 如权利要求 11所述的光时域检测仪光模块， 其特征在于， 所述电信 号采样电路进一步包括放大电路,放大电路置于激光探测器与 ADC电路之间， 对激光探测器输出的电信号进行放大。
13. 如权利要求 4所述的光时域检测仪光模块， 其特征在于， 所述断点 检测模块包括： 检测信号存储单元、 比较单元、 正常运行信号存储单元以及 断点位置确定单元， 其中，
检测信号存储单元， 用于存储 ADC电路在检测状态时输出的数字信号； 正常运行信号存储单元， 用于存储吉比特无源光网络断点检测系统在正 常运行状态时得到的数字信号；
比较单元， 用于比较检测信号存储单元存储的数字信号以及正常运行信 号存储单元存储的数字信号， 输出比较结果；
断点位置确定单元， 用于对比较单元输出的比较结果进行分析， 获取断 点或故障点的位置。
14. 如权利要求 13所述的光时域检测仪光模块， 其特征在于， 所述断点 检测模块为现场可编程门阵列、 可编程阵列逻辑、 单片机、 处理器或微控器。
15.一种吉比特无源光网络断点检测系统，该系统包括：光线路终端 OLT、 分光器以及光网络单元 ONU, 其中， 所述 OLT发射第一波长的光信号， 并接 收所述 ONU发射的第二波长的光信号； 其特征在于， 所述吉比特无源光网络 断点检测系统还包括： 光时域检测仪光模块，
OLT与光时域检测仪光模块相连， 光时域检测仪光模块与分光器相连； 光时域检测仪光模块， 用于接收 OLT输出的第一波长的光信号， 透射至 分光器； 接收 ONU输出的第二波长的光信号， 透射至 OLT; 生成第三波长的 光信号， 进行输出， 接收瑞利散射和菲涅尔反射返回的第三波长的光信号， 进行信号处理， 根据信号处理结果获取断点信息。
16. 如权利要求 15所述的系统， 其特征在于， 所述光时域检测仪光模块 包括： 光路组件、 激光发射器、 激光探测器、 断点检测模块以及电信号采样 电路， 其中，
光路组件， 用于通过内置的上行光纤接口与 OLT相连的光纤相连， 通 过内置的下行光纤接口与分光器相连的光纤相连， 通过内置的激光发射接 口与激光发射器相连， 通过内置的激光接收接口与激光探测器相连；
激光发射器， 用于在进行断点检测时， 生成用于检测断点的第三波长 的光信号， 输出至光路组件的激光发射接口；
激光探测器， 用于接收从光路组件的激光接收接口输出的第三波长的 光信号， 将接收的第三波长的光信号转换为相应的电信号输出；
电信号采样电路， 用于与激光探测器相连， 对激光探测器输出的电信 号进行采样， 得到数字信号， 并发送给断点检测模块；
断点检测模块， 用于接收电信号采样电路发送的数字信号， 进行分析， 将分析结果与预先得到的无断点时采样进行分析得到的结果进行比较， 获 取断点或故障点位置。
17. 如权利要求 16所述的系统， 其特征在于，
所述光路组件通过上行光纤接口接收 OLT通过光纤输出的第一波长的光 信号， 通过下行光纤接口透射至光纤并传输至分光器； 通过下行光纤接口接 收 ONU通过光纤输出的第二波长的光信号，通过上行光纤接口透射至光纤并 传输至所述 OLT; 通过激光发射接口接收激光发射器发射的第三波长的光信号， 输出至下 行光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波 长的光信号， 输出至激光接收接口， 并由激光接收接口输出至激光探测器。
18. 如权利要求 15至 17任一项所述的系统， 其特征在于， 所述光路组 件包括： 波分复用器以及环形器， 其中，
WDM, 通过内置的上行光纤接口接收 OLT通过光纤输出的第一波长 的光信号， 通过下行光纤接口透射至光纤并传输至分光器； 通过下行光纤 接口接收 ONU通过光纤输出的第二波长的光信号， 通过上行光纤接口透 射至光纤并传输至 OLT;
通过内置的反射接口接收环形器输出的第三波长的光信号， 输出至下行 光纤接口， 并由下行光纤接口输出； 通过下行光纤接口接收反射的第三波长 的光信号， 输出至反射接口， 并由反射接口输出至环形器；
环形器， 用于通过内置的第一接口接收激光发射器发射的第三波长的光 信号， 通过内置的第二接口输出至 WDM 的反射接口； 通过第二接口接收 WDM的反射接口输出的反射的第三波长的光信号，并通过内置的激光接收接 口输出至激光探测器。
19. 如权利要求 18所述的系统， 其特征在于， 所述光路组件进一步包括 设置于环形器的激光接收接口与激光探测器之间的滤光片， 所述滤光片用于 增透从环形器的激光接收接口输出的第三波长的光信号。
20. 如权利要求 19所述的系统， 其特征在于， 所述激光发射器包括： 激 光发射单元以及驱动电路单元， 其中，
驱动电路单元， 用于在启动进行断点检测时， 驱动激光发射单元发射第 三波长的激光， 输出至环形器的第一接口。
21. 如权利要求 20所述的系统， 其特征在于， 所述激光发射器进一步包 括：
控制单元， 用于在接收到外部设备的断点检测指令后， 生成断点检测电 信号， 并输出至驱动电路单元， 以使驱动电路单元根据接收的断点检测电信 号， 驱动激光发射单元发射第三波长的激光。
22. 如权利要求 21所述的系统， 其特征在于， 所述激光探测器包括： 光 电二极管以及跨阻放大器 TIA, 其中，
光电二极管， 用于接收从激光接收接口输出的光信号后， 向 TIA输出相 应的响应电流；
TIA, 用于接收响应电流， 根据接收的响应电流向电信号采样电路输出相 应的差分电信号。
23. 如权利要求 22所述的系统， 其特征在于，所述电信号采样电路包括： 模拟数字转换 ADC电路， 用于对激光探测器输出的电信号进行采样， 并 将采样得到的数字信号发送给断点检测模块进行存储；
放大电路， 放大电路置于激光探测器与 ADC电路之间， 对激光探测器输 出的电信号进行放大。
24. 如权利要求 23所述的系统， 其特征在于， 所述断点检测模块包括： 检测信号存储单元、 比较单元、 正常运行信号存储单元以及断点位置确定单 元， 其中，
检测信号存储单元， 用于存储 ADC电路在检测状态时输出的数字信号； 正常运行信号存储单元， 用于存储吉比特无源光网络断点检测系统在正 常运行状态时得到的数字信号；
比较单元， 用于比较检测信号存储单元存储的数字信号以及正常运行信 号存储单元存储的数字信号， 输出比较结果；
断点位置确定单元， 用于对比较单元输出的比较结果进行分析， 获取断 点或故障点的位置。
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