WO2012097554A1 - Optical line terminal, passive optical network system and optical signal transmission method - Google Patents

Optical line terminal, passive optical network system and optical signal transmission method Download PDF

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Publication number
WO2012097554A1
WO2012097554A1 PCT/CN2011/073785 CN2011073785W WO2012097554A1 WO 2012097554 A1 WO2012097554 A1 WO 2012097554A1 CN 2011073785 W CN2011073785 W CN 2011073785W WO 2012097554 A1 WO2012097554 A1 WO 2012097554A1
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WO
WIPO (PCT)
Prior art keywords
optical
fiber
module
wavelength
beam splitter
Prior art date
Application number
PCT/CN2011/073785
Other languages
French (fr)
Chinese (zh)
Inventor
黄茜
陆建鑫
Original Assignee
中兴通讯股份有限公司
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Publication of WO2012097554A1 publication Critical patent/WO2012097554A1/en

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Classifications

    • 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
    • H04B10/25—Arrangements specific to fibre transmission
    • H04B10/2589—Bidirectional transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
    • H04J14/0242—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths in WDM-PON
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0282—WDM tree architectures

Definitions

  • the present invention relates to the field of communications, and in particular, to an Optical Line Terminal (OLT), and a Passive Optical Network (referred to as a Passive Optical Network).
  • OLT Optical Line Terminal
  • Passive Optical Network referred to as a Passive Optical Network
  • PON is a new type of fiber access network technology that uses point-to-multipoint architecture and passive optical fiber transmission to provide multiple services over Ethernet.
  • the PON is composed of an optical line terminal on the central office side, an optical network unit (ONU) on the user side, and an optical distribution network (ODN).
  • the optical signal is transmitted between the OLT and the ONU.
  • the internal components include: optical fiber, passive combiner, passive optical coupler/splitter.
  • PON technology has been widely used, and PON networks have been widely distributed all over the world.
  • 1 is a schematic diagram of a PON system according to the related art. As shown in FIG.
  • an optical module is an indispensable device in a PON system, which is connected to a communication device and an optical fiber to perform optical/electrical/electrical/optical conversion functions.
  • 2 is a schematic diagram of an optical module in a PON system according to the related art. As shown in FIG. 2, the optical modules in the PON system are single-fiber bidirectional structures, and the receiving/transmitting is distinguished by different wavelengths.
  • the optical module in the PON system can be realized by the method of "Bidirectional Optical Subassembly" (BOS A) + circuit board, or can be realized by Planar Lighwave Circuit (PLC).
  • BOS A Beidirectional Optical Subassembly
  • PLC Planar Lighwave Circuit
  • the optical module in the mainstream PON system is usually the former implementation.
  • FIG 3 is a schematic diagram of the internal structure of the optical module in the PON system according to the related art.
  • BOSA will The optical signal sent by the optical fiber is converted into an analog electrical signal, and is connected to the circuit board through a pin.
  • the circuit board converts the analog electrical signal into a digital signal conforming to the standard, and sends it to a subsequent circuit other than the optical module to continue processing; at the transmitting end, the circuit
  • the board converts the standard digital signal into an analog electrical signal and sends it to BOSA through the pin.
  • BOSA converts the analog electrical signal into an optical signal and sends it to the fiber.
  • BOSA is a very important device, which is connected. Light and electricity are the most expensive devices in the entire optical module.
  • FIG. 4 is a schematic diagram of the internal structure of the BOSA according to the related art.
  • the BOSA can be a Receiver Optical Subassembly (ROSA), a Transmitter Optical Subassembly (TOSA), a beam splitter, and a lens. And so on.
  • the function of the beam splitter is to separate the transmitted and received light according to the wavelength. For example, at the receiving end, the light sent from the optical fiber is reflected by the beam splitter and sent to the ROSA. At the transmitting end, the light emitted by the TOSA passes through the beam splitter. Send to the fiber; the role of the lens is to focus.
  • Optical Time Domain Reflectometer is a precision optoelectronic integrated instrument made by Rayleigh scattering and backscattering caused by the transmission of light in an optical fiber. It is widely used in the maintenance and construction of optical cable lines, and can measure the length of fiber, transmission attenuation of optical fiber, joint attenuation and fault location. Simply put, the OTDR works like a radar. It first sends a signal to the fiber and then observes what information is returned from a certain point. In a specific application, the OTDR is performed by transmitting a light pulse into the fiber and then receiving the returned information at the OTDR port.
  • 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, connectors, joints, bends, or other similar events, some of which will return to the OTDR.
  • FIG. 5 is a schematic diagram of a method for using an OTDR according to the related art. As shown in FIG. 5, it is assumed that a primary kilo fiber needs to be detected, and a total of n paths are used.
  • the OTDR is connected to 1: n switch; the wave splitter is connected in series between the OLT and the main kilo-fiber, and the detection light of the OTDR through the multiplexer/demultiplexer and the normal service light of the OLT are integrated into the main kilo-fiber.
  • the main kilofiber 1 is detected first, and the l: n switch is turned on the first path, and the OTDR sends a detection signal (light pulse), and then receives the returned optical signal, and analyzes the detection result; repeat the above steps until the The n-way detection is completed.
  • this method has a drawback: If there is a problem with the fiber between the OLT and the multiplexer (fiber 1 to fiber n in Figure 5), the OTDR will not detect the returned optical signal.
  • a primary object of the present invention is to provide an optical signal transmission scheme to at least solve the above-mentioned related art that an OTDR cannot detect a return optical signal due to an easy failure of an optical fiber between an OLT and a multiplexer/demultiplexer. problem.
  • an OLT is provided.
  • the optical module includes: a transmitting optical module, a receiving optical module, and a multiplexed wave splitting module, wherein the multiplexed wave splitting module is connected to the multiplexed port through the first single-fiber bidirectional optical fiber, and passes through the second single fiber
  • the bidirectional optical fiber is connected to the service port, and is configured to combine the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module and then send the optical signal to the second single-fiber bidirectional optical fiber; and the optical signal from the second single-fiber bidirectional optical fiber according to the wavelength thereof And respectively sent to the corresponding receiving optical module or the first single-fiber bidirectional optical fiber.
  • the multiplex port is an access end of the OTDR, and the service port is a service port of the PON.
  • the multiplex port is a GPON access end, and the service port is a service port of the XGPON.
  • the optical module further comprises a BOSA, and the multiplexed wave splitting module is included in the BOSA.
  • the multiplexer/demultiplexer module comprises a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of: a transmission wavelength of the multiplexer port, a reception wavelength of the multiplexer port, a wavelength of the optical signal transmitted by the transmitting optical module, and a reception.
  • the optical module receives the wavelength of the optical signal.
  • the beam splitter comprises a first beam splitter and a second beam splitter, wherein the first beam splitter is arranged to totally reflect the light signal from the first single-fiber bidirectional fiber to the second beam splitter, and the received light from The optical signal of the second beam splitter is totally reflected to the first single-fiber bidirectional optical fiber; the second splitter is configured to transparently transmit the optical signal from the transmitting optical module to the second single-fiber bidirectional optical fiber, and the second single-fiber bidirectional optical fiber The optical signal matched with the wavelength of the optical signal received by the receiving optical module is transparently transmitted to the receiving optical module; and the received optical signal from the first optical splitter is totally reflected to the second single-fiber bidirectional optical fiber, and the second The optical signal of the single-fiber bidirectional optical fiber that is matched with the receiving wavelength of the combining port is totally reflected to the first beam splitter.
  • the second single-fiber bidirectional optical fiber is a primary optical fiber.
  • a PON includes an OTDR and an OLT, wherein the optical module of the OLT includes: a transmitting optical module, a receiving optical module, and a multiplexed wave splitting module, wherein the multiplexed wave splitting module passes the first single fiber
  • the bidirectional optical fiber is connected to the access end of the OTDR, and is connected to the service port of the PON through the second single-fiber bidirectional optical fiber, and is configured to combine the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module to be sent to the second single-fiber bidirectional And the optical signal from the second single-fiber bidirectional optical fiber is respectively sent to the corresponding receiving optical module or the first single-fiber bidirectional optical fiber according to the wavelength thereof.
  • a method of transmitting an optical signal includes the following steps:
  • the multiplexed wave splitting module in the optical module of the OLT combines the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module in the optical module, and sends the optical signal to the second single
  • the optical fiber signal from the second single-fiber bidirectional optical fiber is respectively sent to the receiving optical module or the first single-fiber bidirectional optical fiber in the corresponding optical module according to the wavelength thereof; wherein the multiplexed wave splitting module passes the first single
  • the fiber bidirectional fiber is connected to the multiplex port, and is connected to the service port through the second single fiber bidirectional fiber.
  • the multiplexed wave splitting module is included in the BOSA of the optical module, wherein the multiplexed wave splitting module comprises a lens and a beam splitter, and the wavelength selection of the splitter depends on at least one of: a transmitting wavelength of the merging port, a multiplexed wave The receiving wavelength of the port, the wavelength at which the transmitting optical module transmits the optical signal, and the wavelength at which the receiving optical module receives the optical signal.
  • the invention solves the problem that the optical fiber between the OLT and the multiplexed wave splitter is prone to failure in the related art by adding a single-fiber two-way multiplexer port and a multiplexed wave splitting module in the optical module of the OLT.
  • FIG. 1 is a schematic diagram of a PON system according to the related art
  • FIG. 2 is a schematic diagram of an optical module in a PON system according to the related art
  • FIG. 10 is a schematic diagram of an OTDR application of an optical module device according to Embodiment 1 of the present invention
  • 11 is a schematic diagram of an optical module device XGPON application according to Embodiment 1 of the present invention
  • FIG. 12 is a schematic diagram of an optical module device according to Embodiment 2 of the present invention
  • FIG. 13 is an optical module device according to Embodiment 2 of the present invention
  • FIG. 14 is a schematic diagram of an XGPON application of an optical module device according to Embodiment 2 of the present invention.
  • FIG. 6 is a structural block diagram of an OLT according to an embodiment of the present invention.
  • the optical module 60 of the OLT includes: a transmitting optical module 62, a receiving optical module 64, and a multiplexing and demultiplexing module 66, where The wave module 66 is connected to the multiplex port through the first single-fiber bidirectional fiber, and is connected to the service port through the second single-fiber bidirectional fiber, and is configured to combine and transmit the optical signals from the first single-fiber bidirectional fiber and the transmitting optical module 62.
  • the OLT is used to add a single-fiber bidirectional (ie, the first single-fiber bidirectional optical fiber) multiplexer and a multiplexed wave splitting module 66 to the optical module 60, thereby solving the related art due to multiplexed wave splitting.
  • the device is set outside the OLT, and the optical fiber between the OLT and the multiplexed wave splitter is prone to failure, which causes the OTDR to detect the problem of the returned optical signal, saves the network device and maintenance cost, and improves the performance of the system.
  • the multiplex port is an access end of the OTDR, and the service port is a service port of the PON of the passive optical network.
  • This method enables the OTDR to perform measurements using the OLT, improving the success rate of OTDR measurements.
  • the multiplex port is a GPON access end, and the service port is a service port of the XGPON.
  • the optical module 60 further includes a BOSA, and the multiplexed wave splitting module 66 is included in the BOSA. The method is simple and practical, and has high operability.
  • the multiplexer/demultiplexing module 66 may include a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of: a transmitting wavelength of the multiplexer port, a receiving wavelength of the multiplexer port, and a transmitting optical module 62 transmitting the optical signal.
  • the wavelength the wavelength at which the receiving optical module 64 receives the optical signal. For example, first, determining a transmission wavelength and a reception wavelength of the multiplex port connected to the first single-fiber bidirectional optical fiber, and a wavelength at which the transmitting optical module 62 transmits the optical signal and a wavelength at which the receiving optical module 64 receives the optical signal;
  • the wavelength is chosen to select the appropriate beam splitter. This method can improve the effectiveness and accuracy of the system.
  • the beam splitter may include a first beam splitter and a second beam splitter, wherein the first beam splitter is configured to totally reflect the optical signal from the first single-fiber bidirectional optical fiber to the second splitter, and to receive the The optical signal from the second beam splitter is totally reflected to the first single-fiber bidirectional optical fiber; the second splitter is configured to transparently transmit the optical signal from the transmitting optical module 62 to the second single-fiber bidirectional optical fiber, which will be from the second single fiber The optical signal of the optical signal of the bidirectional optical fiber and the wavelength of the optical signal received by the receiving optical module 64 are transparently transmitted to the receiving optical module 64; and the received optical signal from the first optical splitter is totally reflected to the second single-fiber bidirectional optical fiber.
  • the method is simple and practical, and has high operability.
  • the transmission wavelength and the reception wavelength of the multiplexer may be the same.
  • the second single-fiber bidirectional optical fiber is a primary optical fiber.
  • the multiplexed wave splitting module 66 is connected to the service port through the main kilofiber. When transmitting, the optical signal transmitted in the main tens of optical fiber is synthesized by the multiplexed wave splitting module 66, including the optical signal in the transmitting optical module 62 and passed through.
  • the first single-fiber bidirectional optical fiber is connected to the optical signal of the multiplexed port; when receiving, the multiplexed wave splitting module 66 transmits the optical signal transmitted in the primary optical fiber to the corresponding receiving optical module 64 according to the wavelength thereof.
  • the multiplexer port of the first single-fiber bidirectional fiber connection According to an embodiment of the present invention, a PON is also provided.
  • FIG. 7 is a structural block diagram of a PON according to an embodiment of the present invention. As shown in FIG.
  • the PON includes an OTDR 72 and the foregoing OLT
  • the optical module 60 includes: a transmitting optical module 62, a receiving optical module 64, and a multiplexed wave splitting module 66, wherein the multiplexed wave splitting module 66 is connected to the access end of the OTDR 72 through the first single-fiber bidirectional optical fiber (ie, The multiplex port is the access end of the OTDR 72;), and is connected to the service port of the PON through the second single-fiber bidirectional optical fiber, and is configured to combine the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module 62 to be sent to the first Two single-fiber bidirectional optical fibers; and optical signals from the second single-fiber bidirectional optical fibers are respectively transmitted according to their wavelengths to corresponding receiving optical modules 64 or first single-fiber bidirectional optical fibers.
  • FIG. 8 is a flowchart of a method for transmitting an optical signal according to an embodiment of the present invention.
  • the method includes the following steps: Step S802, a block of a multiplexed wave splitting mode 66 in an optical module 60 of an OLT will be from a first single-fiber bidirectional optical fiber and light.
  • the optical signals of the transmitting optical module 62 in the module are combined and sent to the second single-fiber bidirectional optical fiber; and in step S804, the multiplexed-wavelength separating module 66 transmits the optical signals from the second single-fiber bidirectional optical fiber to their respective wavelengths.
  • the multiplexer/demultiplexing module 66 is included in the single-fiber bidirectional optical component BOSA of the optical module 60, wherein the multiplexed-wavelength-dividing module 66 includes a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of the following: The transmission wavelength of the wave port (that is, the first single-fiber bidirectional optical fiber is connected to the multiplexed wave splitting module 66), the receiving wavelength of the multiplexing port, the wavelength of the transmitting optical module 62 for transmitting the optical signal, and the receiving optical module 64 for receiving the optical signal.
  • the beam splitter may include a first beam splitter and a second beam splitter.
  • the first beam splitter may totally reflect the light signal from the first single-fiber bidirectional fiber to the second beam splitter, and second The optical splitter can totally reflect the received optical signal from the first splitter to the second single-fiber bidirectional optical fiber; and the second splitter can transparently transmit the optical signal sent by the transmit optical module 62 to the second single-fiber bidirectional optical fiber.
  • the second beam splitter may transparently transmit the optical signal from the optical signal of the second single-fiber bidirectional optical fiber to the wavelength of the optical signal received by the receiving optical module 64 to the receiving optical module 64.
  • Embodiment 1 This embodiment provides an optical module device with a multiplexer port, which can provide an additional optical interface (hereinafter referred to as a multiplex port), and integrate multiple pairs of optical signals into one optical fiber inside the module. OTDR or other services are convenient.
  • the PON optical module can only process a pair of transmitting and receiving optical signals.
  • FIG. 9 is a schematic diagram of an optical module device according to Embodiment 1 of the present invention.
  • a fiber optical port is added to the PON optical module as a multiplexer port; and a multiplexer/demultiplexer module is added inside the optical module.
  • the optical multiplexing/demultiplexing of the light of the module 4 and the service port enables the OTDR or other services to be directly connected to the service port inside the optical module, eliminating external optical fibers, optical switches, multiplexer beamsplitters, etc. .
  • the optical fiber to be detected is the optical fiber of the service port
  • the OTDR uses the wavelength ⁇
  • the upstream wavelength of the PON service (the OLT receiving wavelength) is ⁇ 2
  • the downstream wavelength (the OLT transmission wavelength) is ⁇ 3 .
  • 10 is a schematic diagram of an OTDR application of an optical module device according to the first embodiment of the present invention. As shown in FIG. 10, an OTDR is connected to a multiplex port. When detecting, the OTDR emits an optical signal of a wavelength, such as inside the optical module (for example, The transmitting optical module sends a light signal of wavelength ⁇ 3 to the TOSA.
  • the optical signals of the two wavelengths are combined by the multiplex/split module and sent to the optical fiber of the service port, and the optical signal of the wavelength is the optical fiber of the service port.
  • the transmitted, reflected, and returned optical signals enter the optical module from the service port together with the optical signal of wavelength ⁇ 2 , and are separated from the optical signals of ⁇ 2 by the combining/demultiplexing module, and sent to the OTDR and the optical module respectively.
  • the receiving optical module is ROSA.
  • the downlink wavelength of the 10G GPON is ⁇ 4
  • the upstream wavelength is ⁇ 5
  • the downstream wavelength of the GPON is ⁇ 6
  • the upstream wavelength is ⁇ 7 .
  • FIG. 11 is a schematic diagram of an XGPON application of an optical module device according to Embodiment 1 of the present invention.
  • the GPON service when a GPON service is connected to a multiplex port, when transmitting, the GPON service emits an optical signal having a wavelength of ⁇ 6 , and the optical module internally (For example, TOSA) emits an optical signal of wavelength ⁇ 4 , and the optical signals of the two wavelengths are combined by the combining/demultiplexing module and sent to the optical fiber of the XGPON service port; when receiving, the optical signal with the wavelength of ⁇ 5 is The optical signals with the wavelength ⁇ 7 enter the optical module from the XGPON service port, and the optical signals of the two wavelengths are separated by the multiplex/split module and sent to the GPON service port and the optical module (for example, ROSA).
  • the optical module device in this embodiment provides additional service access by adding a single-fiber bidirectional optical interface (ie, a multiplex port;) and adding a multiplexer/demultiplexer module inside the optical module, for example, additional
  • the service can be OTDR access or PON system service.
  • the l:n switch and the multiplexer/demultiplexer can be omitted, and the problem that the optical fiber between the OLT and the multiplexer/demultiplexer (the optical fiber 1 to the optical fiber n in FIG.
  • the GPON service can be directly integrated into the 10G GPON service to form the XGPON hybrid service, which makes the peripheral optical interface cabling of the OLT device simple and convenient, and saves maintenance costs.
  • the PON optical module implemented in the "BOS A+ circuit board" mode is taken as an example.
  • the multiplexer/demultiplexer module can be encapsulated in the BOSA. That is, the existing BOSA structure is improved by adding one lens and two beamsplitters.
  • 12 is a schematic diagram of an optical module device according to a second embodiment of the present invention. As shown in FIG.
  • FIG. 13 is a schematic diagram of an OTDR application of an optical module device according to Embodiment 2 of the present invention. As shown in FIG. 13, an OTDR is taken as an example to connect an OTDR to a multiplex port, thereby eliminating the 1: switching in the related art. Wave splitter (shown in Figure 5).
  • the beam splitter a is actually a reflective sheet.
  • the operating wavelength of the OTDR is 1625 nm
  • the transmission wavelength of the service port is 1490 nm
  • the receiving wavelength is 1310 nm.
  • the OTDR emits an optical signal of 1625 nm wavelength
  • enters the BOSA through the lens and the reflection sheet a totally reflects it to the beam splitter b.
  • the beam splitter b transmits the light of the wavelengths of 1490 nm and 1310 nm, and totally reflects the light of the wavelength of 1625 nm.
  • FIG. 14 is a schematic diagram of an XGPON application of an optical module device according to Embodiment 2 of the present invention. As shown in FIG. 14, the XGPON is taken as an example to connect a GPON service to a multiplex port.
  • the operating wavelength of the 10G GPON OLT is: transmission wavelength 1577nm, reception wavelength 1270nm; GPON OLT operating wavelength is: transmission wavelength 1490nm, reception wavelength 1310nm.
  • the GPON transmits an optical signal of 1490 nm wavelength through the lens, enters the BOSA through the lens, and the spectroscopic sheet a totally reflects it to the beam splitter b.
  • the beam splitter b transmits the light of 1577 nm and 1270 nm wavelength.
  • the signal is totally reflected and sent to the optical fiber (XGPON access terminal); at the receiving end, the optical signal of 1310 nm wavelength in the optical fiber (XGPON access terminal) is sent to the beam splitter b through the lens, and the beam splitter b totally reflects it to the beam splitter a.
  • the beam splitter a sends it again to the optical fiber (GPON access terminal).
  • the GPON and 10G GPON services can be mixedly connected in the optical module, and the peripheral multiplexer/demultiplexer and the like are omitted, and the use is convenient.
  • the GPON access terminal can be sealed with a fiber plug, and the XGPON can be used as a general 10G GPON service application.
  • the ideas of the embodiments of the present invention are only described herein from two applications. Of course, other similar applications are also within the scope of the present invention.
  • a method of adding a single-fiber bidirectional multiplexer port and a multiplexed wave splitting module in an optical module is used, and the related art is solved between the OLT and the multiplexed demultiplexer.
  • the fiber is prone to failure and the OTDR does not detect the returned optical signal, which saves network equipment and maintenance costs and improves system performance.
  • modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein.
  • the steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module.
  • the invention is not limited to any specific combination of hardware and software.
  • the above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

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Abstract

An optical line terminal, a passive optical network system and an optical signal transmission method are disclosed by the present invention, and the optical modules of the optical line terminal include an optical transmission module, an optical receiving module and a wavelength combination/separation module, wherein the wavelength combination/separation module, which is connected to a wavelength combination interface through a first bi-directional single fiber and connected to a service interface through a second bi-directional single fiber, is used for combining the optical signals from the first bi-directional single fiber and that from the optical transmission module, sending the combined signals to the second bi-directional single fiber, and transmitting the optical signals from the second bi-directional single fiber to the corresponding optical receiving module or the first bi-directional single fiber according to their wavelengths respectively. Thus the present invention saves the network apparatus and the maintenance cost, and improves the system performance.

Description

光线路终端、 无源光网络***及光信号的传输方法 技术领域 本发明涉及通信领域， 尤其涉及一种光线路终端 （Optical Line Terminal, 简称为 OLT ), 无源光网络 （ Passive Optical Network , 简称为 PON ) ***及光 信号的传输方法。 背景技术  TECHNICAL FIELD The present invention relates to the field of communications, and in particular, to an Optical Line Terminal (OLT), and a Passive Optical Network (referred to as a Passive Optical Network). For PON) systems and methods of transmitting optical signals. Background technique
PON是一种新型的光纤接入网技术， 釆用点到多点结构、 无源光纤传输， 在以太网之上提供多种业务。 PON由局端侧的光线路终端、 用户侧的光网络单 元（ Optical Network Unit, 简称为 ONU ) 以及光分配网络 ( Optical Distribution Network, 简称为 ODN )组成。 光信号在 OLT和 ONU之间传送， 信号通道上 没有有源器件， 其内部元件包括： 光纤、 无源组合器、 无源光耦合器 /切分器。 如今， PON技术得到了极其广泛的应用， PON网络已经大规模遍布世界各地。 图 1是根据相关技术的 PON***的示意图， 如图 1所示， 光模块是 PON ***中不可或缺的器件， 它连接着通讯设备和光纤， 完成光 /电、 电 /光转换的 功能。 图 2是根据相关技术的 PON***中光模块的示意图， 如图 2所示， PON ***中的光模块是单纤双向结构， 接收 /发送通过不同的波长来区分。 PON 系 统中的光模块可以用 "单纤双向光组件 （Bidirectional Optical Subassembly, 简 称为 BOS A ) +电路板，，的方式实现， 也可以用平面光波导 （Planar Lighwave Circuit , 简称为 PLC ) 方式实现。 业界主流的 PON ***中的光模块通常釆用的是前一种实现方式。 图 3是 根据相关技术的 PON ***中光模块的内部结构示意图， 如图 3所示， 在接收 端， BOSA将光纤送来的光信号转换成模拟电信号， 通过管脚连接到电路板， 电路板将模拟电信号转换成符合标准的数字信号， 送给光模块以外的后续电路 继续处理； 在发送端， 电路板将符合标准的数字信号转换成模拟电信号， 通过 管脚送给 BOSA, BOSA将模拟电信号转换成光信号， 发送至光纤中。 在光模块中， BOSA是非常重要的器件， 它联系着光与电， 是整个光模块 中成本最高的器件。 图 4是根据相关技术的 BOSA的内部结构示意图， 如图 4 所示， BOSA可以由接收光组件（ Receiver Optical Subassembly,简称为 ROSA ), 发送光组件 （ Transmitter Optical Subassembly, 简称为 TOSA )、 分光片、 透镜 等组成。 其中， 分光片的作用是按波长把发送、 接收的光分开， 例如， 在接收 端， 光纤中发过来的光经分光片反射后送给 ROSA, 在发送端， TOSA发出的 光透过分光片送给光纤； 透镜的作用是聚焦。 即相关技术中， PON BOSA只处 理一对光信号 （两种波长） 的收发。 光时 i或反射仪 （ Optical Time Domain Reflectometer, 简称为 OTDR ) 是利 用光在光纤中传输时的瑞利散射和菲淫尔反射所产生的背向散射而制成的精 密的光电一体化仪表， 它被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。 简单的说， OTDR的工作原理类似于一个雷达。它先对光纤发出一个信号， 然后观察从某一点上返回来的是什么信息。 具体应用中， OTDR是通过发射光 脉冲到光纤内， 然后在 OTDR端口接收返回的信息来进行。 当光脉冲在光纤内 传输时， 会由于光纤本身的性质、 连接器、 接合点、 弯曲或其它类似的事件而 产生散射和反射， 其中一部分的散射和反射就会返回到 OTDR中。 返回的有用 信息由 OTDR的探测器来测量，它们就作为光纤内不同位置上的时间或曲线片 断。 从发射信号到返回信号所用的时间， 再确定光在玻璃物质中的速度就可以 计算出距离。 以下的公式说明了 OTDR是如何测量距离的。 d = (c t ) / 2 ( IOR ) 上述公式中： d 距离， c 光在真空中的速度， t一信号发射后到接收到信 号 （双程） 的总时间， IOR 被测光纤的折射率。 目前， PON技术得到了极其广泛的应用， PON 网络已经大规模遍布世界 各地， 光缆线路的维护、 施工非常需要 OTDR技术。 图 5 是根据相关技术的 OTDR的使用方法示意图， 如图 5所示， 假设需要检测的是主千光纤， 共有 n 路。 OTDR接 1: n开关； 在 OLT和主千光纤之间串接合波分波器， 通过合波分 波器 4巴 OTDR的检测光和 OLT的正常业务光合入主千光纤。 检测时， 先检测 主千光纤 1 , 将 l : n开关接通第 1路， OTDR发出检测信号（光脉冲）， 之后接 收返回来的光信号， 分析得出检测结果； 重复上述步骤， 直至第 n路检测完成。 但是， 此方法有一个缺陷： 如果 OLT与合波分波器之间的光纤（图 5中的光纤 1〜光纤 n ) 出现问题， 则 OTDR将检测不到返回的光信号。 发明内容 本发明的主要目的在于提供一种光信号的传输方案， 以至少解决上述相关 技术中由于 OLT与合波分波器之间的光纤容易出现故障而导致 OTDR检测不 到返回的光信号的问题。 为了实现上述目的， 才艮据本发明的一个方面， 提供了一种 OLT。 根据本发明的 OLT, 其光模块包括： 发送光模块、 接收光模块和合波分波 模块， 其中， 合波分波模块， 通过第一单纤双向光纤与合波口相连， 通过第二 单纤双向光纤与业务口相连， 设置为将来自第一单纤双向光纤和发送光模块的 光信号合并后发送至第二单纤双向光纤； 以及将来自第二单纤双向光纤的光信 号根据其波长分别发送至对应的接收光模块或第一单纤双向光纤。 优选地， 合波口为 OTDR的接入端， 业务口为 PON的业务口。 优选地， 合波口为 GPON接入端， 业务口为 XGPON的业务口。 优选地， 光模块还包括 BOSA, 合波分波模块包含于 BOSA。 优选地， 合波分波模块包括透镜和分光片， 分光片的波长选择依赖于以下 至少之一： 合波口的发送波长、 合波口的接收波长、 发送光模块发送光信号的 波长、 接收光模块接收光信号的波长。 优选地， 分光片包括第一分光片和第二分光片， 其中， 第一分光片， 设置 为将来自第一单纤双向光纤的光信号全反射至第二分光片， 以及将接收到的来 自第二分光片的光信号全反射至第一单纤双向光纤； 第二分光片， 设置为将来 自发送光模块的光信号透传至第二单纤双向光纤， 将来自第二单纤双向光纤的 光信号中与接收光模块接收光信号的波长匹配的光信号透传至接收光模块； 以 及将接收到的来自第一分光片的光信号全反射至第二单纤双向光纤， 将第二单 纤双向光纤的光信号中与合波口的接收波长匹配的光信号全反射至第一分光 片。 优选地， 第二单纤双向光纤为主千光纤。 为了实现上述目的， 根据本发明的另一方面， 提供了一种 PON。 根据本发明的 PON, 包括 OTDR和 OLT, 其中， OLT的光模块包括： 发 送光模块、 接收光模块和合波分波模块， 其中， 合波分波模块， 通过第一单纤 双向光纤与 OTDR的接入端相连， 通过第二单纤双向光纤与 PON的业务口相 连， 设置为将来自第一单纤双向光纤和发送光模块的光信号合并后发送至第二 单纤双向光纤； 以及将来自第二单纤双向光纤的光信号才艮据其波长分别发送至 对应的接收光模块或第一单纤双向光纤。 为了实现上述目的， 根据本发明的又一方面， 还提供了一种光信号的传输 方法。 根据本发明的光信号的传输方法， 包括以下步骤： OLT的光模块中的合波 分波模块将来自第一单纤双向光纤和光模块中的发送光模块的光信号合并后 发送至第二单纤双向光纤； 以及将来自第二单纤双向光纤的光信号根据其波长 分别发送至对应的光模块中的接收光模块或第一单纤双向光纤； 其中， 合波分 波模块通过第一单纤双向光纤与合波口相连， 通过第二单纤双向光纤与业务口 相连。 优选地， 合波分波模块包含于光模块的 BOSA中， 其中， 合波分波模块包 括透镜和分光片，分光片的波长选择依赖于以下至少之一：合波口的发送波长、 合波口的接收波长、 发送光模块发送光信号的波长、 接收光模块接收光信号的 波长。 通过本发明 ,釆用在 OLT的光模块中增加一个单纤双向合波口和一个合波 分波模块的方式，解决了相关技术中由于 OLT与合波分波器之间的光纤容易出 现故障而导致 OTDR检测不到返回的光信号的问题， 节省了器件和维护成本， 提高了***的性能。 附图说明 此处所说明的附图用来提供对本发明的进一步理解， 构成本申请的一部 分， 本发明的示意性实施例及其说明用于解释本发明， 并不构成对本发明的不 当限定。 在附图中： 图 1是根据相关技术的 PON***的示意图； 图 2是根据相关技术的 PON***中光模块的示意图； 图 3是根据相关技术的 PON***中光模块的内部结构示意图； 图 4是根据相关技术的 PON BOSA的内部结构示意图； 图 5是根据相关技术的 OTDR的使用方法示意图； 图 6是才艮据本发明实施例的 OLT的结构框图； 图 7是才艮据本发明实施例的 PON的结构框图； 图 8是根据本发明实施例的光信号的传输方法的流程图； 图 9是 居本发明实施例一的光模块装置的示意图； 图 10是才艮据本发明实施例一的光模块装置 OTDR应用的示意图； 图 11是才艮据本发明实施例一的光模块装置 XGPON应用的示意图； 图 12是根据本发明实施例二的光模块装置的示意图； 图 13是才艮据本发明实施例二的光模块装置 OTDR应用的示意图； 图 14是才艮据本发明实施例二的光模块装置 XGPON应用的示意图。 具体实施方式 下文中将参考附图并结合实施例来详细说明本发明。 需要说明的是， 在不 冲突的情况下， 本申请中的实施例及实施例中的特征可以相互组合。 才艮据本发明实施例， 提供了一种 OLT。 图 6是才艮据本发明实施例的 OLT 的结构框图， 如图 6所示， OLT的光模块 60包括： 发送光模块 62、 接收光模 块 64和合波分波模块 66 , 其中， 合波分波模块 66 , 通过第一单纤双向光纤与 合波口相连， 通过第二单纤双向光纤与业务口相连， 设置为将来自第一单纤双 向光纤和发送光模块 62 的光信号合并后发送至第二单纤双向光纤； 以及将来 自第二单纤双向光纤的光信号根据其波长分别发送至对应的接收光模块 64 或 第一单纤双向光纤。 通过上述 OLT, 釆用在光模块 60 中增加一个单纤双向 （即， 第一单纤双 向光纤）合波口和一个合波分波模块 66 的方式， 解决了相关技术中由于合波 分波器设置在 OLT之外， OLT与合波分波器之间的光纤容易出现故障而导致 OTDR检测不到返回的光信号的问题， 节省了网络器件和维护成本， 提高了系 统的性能。 优选地， 合波口为 OTDR的接入端， 业务口为无源光网络 PON的业务口。 该方法使得 OTDR可以利用该 OLT进行测量， 提高了 OTDR测量的成功率。 优选地， 合波口为 GPON接入端， 业务口为 XGPON的业务口。 该方法可 以提高***的兼容性和灵活性。 优选地， 光模块 60还包括 BOSA, 合波分波模块 66包含于 BOSA。 该方 法简单实用、 可操作性强。 优选地， 合波分波模块 66 可以包括透镜和分光片， 分光片的波长选择依 赖于以下至少之一： 合波口的发送波长、 合波口的接收波长、 发送光模块 62 发送光信号的波长、 接收光模块 64接收光信号的波长。 例如， 首先确定与第 一单纤双向光纤相连的合波口的发送波长和接收波长， 以及发送光模块 62 发 送光信号的波长和接收光模块 64接收光信号的波长； 然后再根据确定的上述 波长来选择合适的分光片。 该方法可以提高***的有效性和准确性。 优选地， 分光片可以包括第一分光片和第二分光片， 其中， 第一分光片， 设置为将来自第一单纤双向光纤的光信号全反射至第二分光片， 以及将接收到 的来自第二分光片的光信号全反射至第一单纤双向光纤； 第二分光片， 设置为 将来自发送光模块 62 的光信号透传至第二单纤双向光纤， 将来自第二单纤双 向光纤的光信号中与接收光模块 64接收光信号的波长匹配的光信号透传至接 收光模块 64; 以及将接收到的来自第一分光片的光信号全反射至第二单纤双向 光纤， 将第二单纤双向光纤的光信号中与合波口的接收波长匹配的光信号全反 射至第一分光片。 该方法简单实用、 可操作性强。 需要说明的是， 在合波口为 OTDR的接入端的情况下， 所述合波口的发送 波长和接收波长可以是相同的。 优选地， 第二单纤双向光纤为主千光纤。 例如， 合波分波模块 66 通过主 千光纤与业务口相连， 发送时， 主千光纤中传输的光信号是经过合波分波模块 66合成的、 包括发送光模块 62中的光信号和通过第一单纤双向光纤从合波口 接入的光信号； 接收时， 合波分波模块 66 是将主千光纤中传输的光信号根据 其波长情况分别发送至对应的接收光模块 64 或通过第一单纤双向光纤连接的 合波口。 才艮据本发明实施例，还提供了一种 PON。 图 7是根据本发明实施例的 PON 的结构框图， 如图 7所示， 该PON包括OTDR 72和上述OLT, 其中， OLT的 光模块 60包括： 发送光模块 62、 接收光模块 64和合波分波模块 66 , 其中， 合波分波模块 66 , 通过第一单纤双向光纤与 OTDR 72的接入端相连 （即， 此 时合波口为 OTDR 72的接入端；)， 通过第二单纤双向光纤与 PON的业务口相 连， 设置为将来自第一单纤双向光纤和发送光模块 62 的光信号合并后发送至 第二单纤双向光纤； 以及将来自第二单纤双向光纤的光信号根据其波长分别发 送至对应的接收光模块 64或第一单纤双向光纤。 对应于上述 OLT, 本发明实施还提供了一种光信号的传输方法。 图 8是根 据本发明实施例的光信号的传输方法的流程图， 该方法包括以下步骤： 步骤 S802, OLT的光模块 60中的合波分波模 66块将来自第一单纤双向 光纤和光模块中的发送光模块 62 的光信号合并后发送至第二单纤双向光纤； 以及 步骤 S804, 合波分波模块 66将来自第二单纤双向光纤的光信号 居其波 长分别发送至对应的光模块中的接收光模块 64或第一单纤双向光纤； 其中， 合波分波模块 66 通过第一单纤双向光纤与合波口相连， 通过第二 单纤双向光纤与业务口相连。 通过上述步 4聚， 釆用在 OLT的光模块 60中增加一个单纤双向合波口和一 个合波分波模块 66的方式， 解决了相关技术中由于合波分波器设置在 OLT之 夕卜， OLT与合波分波器之间的光纤容易出现故障而导致 OTDR检测不到返回的 光信号的问题， 节省了网络器件和维护成本， 提高了***的性能。 优选地， 合波分波模块 66包含于光模块 60的单纤双向光组件 BOSA中， 其中， 合波分波模块 66 包括透镜和分光片， 分光片的波长选择依赖于以下至 少之一： 合波口 （即， 通过第一单纤双向光纤与合波分波模块 66 相连） 的发 送波长、 合波口的接收波长、 发送光模块 62 发送光信号的波长、 接收光模块 64接收光信号的波长。 在实施过程中， 分光片可以包括第一分光片和第二分光片， 在步骤 S802 中， 第一分光片可以将来自第一单纤双向光纤的光信号全反射至第二分光片， 第二分光片可以将接收到的来自第一分光片的光信号全反射至第二单纤双向 光纤； 以及第二分光片可以将发送光模块 62 发送的光信号透传至第二单纤双 向光纤。 在步骤 S804 中， 第二分光片可以将来自第二单纤双向光纤的光信号 中与接收光模块 64接收光信号的波长匹配的光信号透传至接收光模块 64 , 可 以将第二单纤双向光纤的光信号中与合波口的接收波长匹配的光信号全反射 至第一分光片； 以及第一分光片可以将接收到的来自第二分光片的光信号全反 射至第一单纤双向光纤。 下面结合优选实施例和附图对上述实施例的实现过程进行详细说明。 实施例一 本实施例提供了一种带有合波口的光模块装置， 能够提供额外的光接口 (下称合波口）， 在模块内部将多对光信号合入一根光纤中， 为 OTDR或其它 业务提供方便。 而相关技术中 PON光模块只能处理一对发送、 接收光信号。 图 9是 居本发明实施例一的光模块装置的示意图， 如图 9所示， 在 PON 光模块上增加一个光纤接入口作为合波口； 在光模块内部增加合波 /分波模块， 通过该模块 4巴合波口的光与业务口的光合波 /分波， 使得 OTDR或其他业务在 光模块内部直接接入到业务口， 省去外部的光纤、 光开关、合波分光器等器件。 以 OTDR应用为例， 假设需要检测的光纤为业务口的光纤， OTDR使用波 长 λι , PON业务上行波长 ( OLT接收波长 ) 为 λ2, 下行波长 ( OLT发送波长 ) 为 λ3。 图 10是才艮据本发明实施例一的光模块装置 OTDR应用的示意图， 如图 10所示， 将 OTDR接入合波口， 检测时， OTDR发出波长为 的光信号， 光 模块内部 （例如， 发送光模块为 TOSA )发出波长为 λ3的光信号， 这两种波长 的光信号经合波 /分波模块合并后发送至业务口的光纤中， 波长为 的光信号 在业务口的光纤中传输、 反射， 返回来的光信号与波长为 λ2的光信号一起从业 务口进入光模块，再由合波 /分波模块将 和 λ2的光信号分开，分别送至 OTDR 和光模块内部 （例如， 接收光模块为 ROSA )。 以 XGPON应用为例， 個―设 10G GPON下行波长为 λ4, 上行波长为 λ5, GPON下行波长为 λ6, 上行波长为 λ7。 图 11是根据本发明实施例一的光模块 装置 XGPON应用的示意图， 如图 11所示， 将 GPON业务接入合波口， 发送 时， GPON业务发出波长为 λ6的光信号， 光模块内部 （例如， TOSA )发出波 长为 λ4的光信号，这两种波长的光信号经合波 /分波模块合并后发送至 XGPON 业务口的光纤中； 接收时， 波长为 λ5的光信号与波长为 λ7的光信号一起从 XGPON业务口进入光模块， 再由合波 /分波模块将这两种波长的光信号分开， 分别送至 GPON业务口和光模块内部 （例如， ROSA )。 可见， 本实施例中的光模块装置通过增加一个单纤双向光接口 （即， 合波 口；)、 在光模块内部增加一个合波 /分波模块， 提供了额外业务接入， 例如， 额 外的业务可以是 OTDR接入， 也可以是 PON***的业务。 应用于 OTDR时， 可以省去 l: n开关、 合波分波器， 也解决了 OLT与合波分波器之间的光纤（图 5中的光纤 1〜光纤 n )检测不到的问题；应用于 XGPON***时，可以将 GPON 业务直接合入到 10G GPON业务， 组成 XGPON混合业务， 使得 OLT设备外 围光接口布线简单方便， 节省了维护的成本。 实施例二 以 "BOS A+电路板"方式实现的 PON光模块为例， 在实施过程中， 可以将 上述合波 /分波模块封装在 BOSA内。 即， 改进现有的 BOSA结构， 增加一个 透镜和两个分光片。 图 12是才艮据本发明实施例二的光模块装置的示意图， 如图 12所示， 分光 片 a把合波口的光全反射至分光片 b; 分光片 b可根据波长选择， 对于业务口 的光， 分光片 b相当于透明， 让业务口的光透过， 对于合波口的光， 分光片 b 全反射， 让合波口的光合入正常业务端的光纤内。 图 13是根据本发明实施例二的光模块装置 OTDR应用的示意图， 如图 13 所示， 以 OTDR为例， 将 OTDR接入合波口， 从而省去相关技术中的 1： n开 关、 合波分波器 （图 5 中所示）。 在这种应用中， 分光片 a实际上是反射片。 £设 OTDR的工作波长是 1625nm, 业务口的发送波长是 1490nm, 接收波长是 1310nm。 检测时， OTDR发出 1625nm波长的光信号， 经透镜进入 BOSA内， 反射片 a将其全反射至分光片 b, 分光片 b将 1490nm、 1310nm波长的光透传， 将 1625nm波长的光全反射， 送入业务口的光纤 （待检测的光纤） 中， 1625nm 波长的光信号在光纤中传输， 返回来的光信号经透镜后送至分光片 b, 全反射 至反射片 a, 再次全反射至 OTDR中分析， 从而完成一次检测。 不检测时， 合 波口可以用光纤堵头封上， 与普通 PON模块应用无区别。 图 14是才艮据本发明实施例二的光模块装置 XGPON应用的示意图， 如图 14所示， 以 XGPON为例， 将 GPON业务接入合波口。 10G GPON OLT的工 作波长是： 发送波长 1577nm, 接收波长 1270nm; GPON OLT的工作波长是： 发送波长 1490nm, 接收波长 1310nm。 将 GPON业务接入时， 发送端， GPON 发送 1490nm波长的光信号， 经过透镜进入 BOSA内， 分光片 a将其全反射至 分光片 b, 分光片 b将 1577nm、 1270nm波长的光透传， 将 1490nm波长的光 信号全反射， 送入光纤 （ XGPON接入端）； 接收端， 光纤 （XGPON接入端） 中 1310nm波长的光信号经透镜送至分光片 b,分光片 b将其全反射至分光片 a, 分光片 a将其再次全反射送入光纤 （ GPON接入端）。 这样， 可实现在光模块 内将 GPON、 10G GPON业务混合接入， 省去了***的合波分波器等器件， 且 使用方便。在不需 GPON业务时， GPON接入端可以用光纤堵头封上， XGPON 可用作普通 10G GPON业务应用。 需要说明的是， 这里只从两个应用阐述了本发明实施例的思想， 当然， 其 它相似的应用也在本发明保护范围之内。 综上所述， 通过本发明实施例， 釆用在光模块中增加一个单纤双向合波口 和一个合波分波模块的方式，解决了相关技术中由于 OLT与合波分波器之间的 光纤容易出现故障而导致 OTDR检测不到返回的光信号的问题，节省了网络器 件和维护成本， 提高了***的性能。 显然， 本领域的技术人员应该明白， 上述的本发明的各模块或各步骤可以 用通用的计算装置来实现， 它们可以集中在单个的计算装置上， 或者分布在多 个计算装置所组成的网络上， 可选地， 它们可以用计算装置可执行的程序代码 来实现， 从而， 可以将它们存储在存储装置中由计算装置来执行， 并且在某些 情况下， 可以以不同于此处的顺序执行所示出或描述的步骤， 或者将它们分别 制作成各个集成电路模块， 或者将它们中的多个模块或步骤制作成单个集成电 路模块来实现。 这样， 本发明不限制于任何特定的硬件和软件结合。 以上所述仅为本发明的优选实施例而已， 并不用于限制本发明， 对于本领 域的技术人员来说， 本发明可以有各种更改和变化。 凡在本发明的 ^"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。 PON is a new type of fiber access network technology that uses point-to-multipoint architecture and passive optical fiber transmission to provide multiple services over Ethernet. The PON is composed of an optical line terminal on the central office side, an optical network unit (ONU) on the user side, and an optical distribution network (ODN). The optical signal is transmitted between the OLT and the ONU. There are no active devices on the signal path. The internal components include: optical fiber, passive combiner, passive optical coupler/splitter. Nowadays, PON technology has been widely used, and PON networks have been widely distributed all over the world. 1 is a schematic diagram of a PON system according to the related art. As shown in FIG. 1, an optical module is an indispensable device in a PON system, which is connected to a communication device and an optical fiber to perform optical/electrical/electrical/optical conversion functions. 2 is a schematic diagram of an optical module in a PON system according to the related art. As shown in FIG. 2, the optical modules in the PON system are single-fiber bidirectional structures, and the receiving/transmitting is distinguished by different wavelengths. The optical module in the PON system can be realized by the method of "Bidirectional Optical Subassembly" (BOS A) + circuit board, or can be realized by Planar Lighwave Circuit (PLC). The optical module in the mainstream PON system is usually the former implementation. Figure 3 is a schematic diagram of the internal structure of the optical module in the PON system according to the related art. As shown in Figure 3, at the receiving end, BOSA will The optical signal sent by the optical fiber is converted into an analog electrical signal, and is connected to the circuit board through a pin. The circuit board converts the analog electrical signal into a digital signal conforming to the standard, and sends it to a subsequent circuit other than the optical module to continue processing; at the transmitting end, the circuit The board converts the standard digital signal into an analog electrical signal and sends it to BOSA through the pin. BOSA converts the analog electrical signal into an optical signal and sends it to the fiber. In the optical module, BOSA is a very important device, which is connected. Light and electricity are the most expensive devices in the entire optical module. Figure 4 is a schematic diagram of the internal structure of the BOSA according to the related art. As shown in FIG. 4, the BOSA can be a Receiver Optical Subassembly (ROSA), a Transmitter Optical Subassembly (TOSA), a beam splitter, and a lens. And so on. The function of the beam splitter is to separate the transmitted and received light according to the wavelength. For example, at the receiving end, the light sent from the optical fiber is reflected by the beam splitter and sent to the ROSA. At the transmitting end, the light emitted by the TOSA passes through the beam splitter. Send to the fiber; the role of the lens is to focus. That is, in the related art, the PON BOSA processes only one pair of optical signals (two wavelengths) for transmission and reception. Optical Time Domain Reflectometer (OTDR) is a precision optoelectronic integrated instrument made by Rayleigh scattering and backscattering caused by the transmission of light in an optical fiber. It is widely used in the maintenance and construction of optical cable lines, and can measure the length of fiber, transmission attenuation of optical fiber, joint attenuation and fault location. Simply put, the OTDR works like a radar. It first sends a signal to the fiber and then observes what information is returned from a certain point. In a specific application, the OTDR is performed by transmitting a light pulse into the fiber and then receiving the returned information at the OTDR port. When a light pulse is transmitted within an optical fiber, it will scatter and reflect due to the nature of the fiber itself, connectors, joints, bends, or other similar events, some of which will return to the OTDR. The useful information returned is measured by the OTDR detectors as a time or curve segment at different locations within the fiber. The distance can be calculated from the time it takes to transmit the signal to the return signal, and then determine the speed of the light in the glass material. The following formula shows how the OTDR measures distance. d = (ct ) / 2 ( IOR ) In the above formula: d distance, the speed of c light in vacuum, the total time after t-signal transmission to the received signal (two-way), IOR the refractive index of the fiber under test. At present, PON technology has been widely used. The PON network has been widely distributed all over the world. The maintenance and construction of optical cable lines require OTDR technology. FIG. 5 is a schematic diagram of a method for using an OTDR according to the related art. As shown in FIG. 5, it is assumed that a primary kilo fiber needs to be detected, and a total of n paths are used. The OTDR is connected to 1: n switch; the wave splitter is connected in series between the OLT and the main kilo-fiber, and the detection light of the OTDR through the multiplexer/demultiplexer and the normal service light of the OLT are integrated into the main kilo-fiber. During the detection, the main kilofiber 1 is detected first, and the l: n switch is turned on the first path, and the OTDR sends a detection signal (light pulse), and then receives the returned optical signal, and analyzes the detection result; repeat the above steps until the The n-way detection is completed. However, this method has a drawback: If there is a problem with the fiber between the OLT and the multiplexer (fiber 1 to fiber n in Figure 5), the OTDR will not detect the returned optical signal. SUMMARY OF THE INVENTION A primary object of the present invention is to provide an optical signal transmission scheme to at least solve the above-mentioned related art that an OTDR cannot detect a return optical signal due to an easy failure of an optical fiber between an OLT and a multiplexer/demultiplexer. problem. In order to achieve the above object, according to an aspect of the present invention, an OLT is provided. According to the OLT of the present invention, the optical module includes: a transmitting optical module, a receiving optical module, and a multiplexed wave splitting module, wherein the multiplexed wave splitting module is connected to the multiplexed port through the first single-fiber bidirectional optical fiber, and passes through the second single fiber The bidirectional optical fiber is connected to the service port, and is configured to combine the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module and then send the optical signal to the second single-fiber bidirectional optical fiber; and the optical signal from the second single-fiber bidirectional optical fiber according to the wavelength thereof And respectively sent to the corresponding receiving optical module or the first single-fiber bidirectional optical fiber. Preferably, the multiplex port is an access end of the OTDR, and the service port is a service port of the PON. Preferably, the multiplex port is a GPON access end, and the service port is a service port of the XGPON. Preferably, the optical module further comprises a BOSA, and the multiplexed wave splitting module is included in the BOSA. Preferably, the multiplexer/demultiplexer module comprises a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of: a transmission wavelength of the multiplexer port, a reception wavelength of the multiplexer port, a wavelength of the optical signal transmitted by the transmitting optical module, and a reception. The optical module receives the wavelength of the optical signal. Preferably, the beam splitter comprises a first beam splitter and a second beam splitter, wherein the first beam splitter is arranged to totally reflect the light signal from the first single-fiber bidirectional fiber to the second beam splitter, and the received light from The optical signal of the second beam splitter is totally reflected to the first single-fiber bidirectional optical fiber; the second splitter is configured to transparently transmit the optical signal from the transmitting optical module to the second single-fiber bidirectional optical fiber, and the second single-fiber bidirectional optical fiber The optical signal matched with the wavelength of the optical signal received by the receiving optical module is transparently transmitted to the receiving optical module; and the received optical signal from the first optical splitter is totally reflected to the second single-fiber bidirectional optical fiber, and the second The optical signal of the single-fiber bidirectional optical fiber that is matched with the receiving wavelength of the combining port is totally reflected to the first beam splitter. Preferably, the second single-fiber bidirectional optical fiber is a primary optical fiber. In order to achieve the above object, according to another aspect of the present invention, a PON is provided. The PON according to the present invention includes an OTDR and an OLT, wherein the optical module of the OLT includes: a transmitting optical module, a receiving optical module, and a multiplexed wave splitting module, wherein the multiplexed wave splitting module passes the first single fiber The bidirectional optical fiber is connected to the access end of the OTDR, and is connected to the service port of the PON through the second single-fiber bidirectional optical fiber, and is configured to combine the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module to be sent to the second single-fiber bidirectional And the optical signal from the second single-fiber bidirectional optical fiber is respectively sent to the corresponding receiving optical module or the first single-fiber bidirectional optical fiber according to the wavelength thereof. In order to achieve the above object, according to still another aspect of the present invention, a method of transmitting an optical signal is also provided. The method for transmitting an optical signal according to the present invention includes the following steps: The multiplexed wave splitting module in the optical module of the OLT combines the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module in the optical module, and sends the optical signal to the second single And the optical fiber signal from the second single-fiber bidirectional optical fiber is respectively sent to the receiving optical module or the first single-fiber bidirectional optical fiber in the corresponding optical module according to the wavelength thereof; wherein the multiplexed wave splitting module passes the first single The fiber bidirectional fiber is connected to the multiplex port, and is connected to the service port through the second single fiber bidirectional fiber. Preferably, the multiplexed wave splitting module is included in the BOSA of the optical module, wherein the multiplexed wave splitting module comprises a lens and a beam splitter, and the wavelength selection of the splitter depends on at least one of: a transmitting wavelength of the merging port, a multiplexed wave The receiving wavelength of the port, the wavelength at which the transmitting optical module transmits the optical signal, and the wavelength at which the receiving optical module receives the optical signal. The invention solves the problem that the optical fiber between the OLT and the multiplexed wave splitter is prone to failure in the related art by adding a single-fiber two-way multiplexer port and a multiplexed wave splitting module in the optical module of the OLT. The problem that the OTDR does not detect the returned optical signal saves device and maintenance costs and improves system performance. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic diagram of a PON system according to the related art; FIG. 2 is a schematic diagram of an optical module in a PON system according to the related art; FIG. 3 is a schematic diagram of an internal structure of an optical module in a PON system according to the related art; 4 is a schematic diagram of the internal structure of the PON BOSA according to the related art; 5 is a schematic structural diagram of a OLT according to an embodiment of the present invention; FIG. 7 is a structural block diagram of a PON according to an embodiment of the present invention; FIG. 7 is a structural block diagram of a PON according to an embodiment of the present invention; FIG. 9 is a schematic diagram of an optical module device according to Embodiment 1 of the present invention; FIG. 10 is a schematic diagram of an OTDR application of an optical module device according to Embodiment 1 of the present invention; 11 is a schematic diagram of an optical module device XGPON application according to Embodiment 1 of the present invention; FIG. 12 is a schematic diagram of an optical module device according to Embodiment 2 of the present invention; FIG. 13 is an optical module device according to Embodiment 2 of the present invention; FIG. 14 is a schematic diagram of an XGPON application of an optical module device according to Embodiment 2 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. According to an embodiment of the present invention, an OLT is provided. FIG. 6 is a structural block diagram of an OLT according to an embodiment of the present invention. As shown in FIG. 6, the optical module 60 of the OLT includes: a transmitting optical module 62, a receiving optical module 64, and a multiplexing and demultiplexing module 66, where The wave module 66 is connected to the multiplex port through the first single-fiber bidirectional fiber, and is connected to the service port through the second single-fiber bidirectional fiber, and is configured to combine and transmit the optical signals from the first single-fiber bidirectional fiber and the transmitting optical module 62. Up to the second single-fiber bidirectional optical fiber; and transmitting the optical signal from the second single-fiber bidirectional optical fiber to the corresponding receiving optical module 64 or the first single-fiber bidirectional optical fiber according to the wavelength thereof. The OLT is used to add a single-fiber bidirectional (ie, the first single-fiber bidirectional optical fiber) multiplexer and a multiplexed wave splitting module 66 to the optical module 60, thereby solving the related art due to multiplexed wave splitting. The device is set outside the OLT, and the optical fiber between the OLT and the multiplexed wave splitter is prone to failure, which causes the OTDR to detect the problem of the returned optical signal, saves the network device and maintenance cost, and improves the performance of the system. Preferably, the multiplex port is an access end of the OTDR, and the service port is a service port of the PON of the passive optical network. This method enables the OTDR to perform measurements using the OLT, improving the success rate of OTDR measurements. Preferably, the multiplex port is a GPON access end, and the service port is a service port of the XGPON. This approach can increase system compatibility and flexibility. Preferably, the optical module 60 further includes a BOSA, and the multiplexed wave splitting module 66 is included in the BOSA. The method is simple and practical, and has high operability. Preferably, the multiplexer/demultiplexing module 66 may include a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of: a transmitting wavelength of the multiplexer port, a receiving wavelength of the multiplexer port, and a transmitting optical module 62 transmitting the optical signal. The wavelength, the wavelength at which the receiving optical module 64 receives the optical signal. For example, first, determining a transmission wavelength and a reception wavelength of the multiplex port connected to the first single-fiber bidirectional optical fiber, and a wavelength at which the transmitting optical module 62 transmits the optical signal and a wavelength at which the receiving optical module 64 receives the optical signal; The wavelength is chosen to select the appropriate beam splitter. This method can improve the effectiveness and accuracy of the system. Preferably, the beam splitter may include a first beam splitter and a second beam splitter, wherein the first beam splitter is configured to totally reflect the optical signal from the first single-fiber bidirectional optical fiber to the second splitter, and to receive the The optical signal from the second beam splitter is totally reflected to the first single-fiber bidirectional optical fiber; the second splitter is configured to transparently transmit the optical signal from the transmitting optical module 62 to the second single-fiber bidirectional optical fiber, which will be from the second single fiber The optical signal of the optical signal of the bidirectional optical fiber and the wavelength of the optical signal received by the receiving optical module 64 are transparently transmitted to the receiving optical module 64; and the received optical signal from the first optical splitter is totally reflected to the second single-fiber bidirectional optical fiber. And optically reflecting the optical signal of the optical signal of the second single-fiber bidirectional optical fiber and the receiving wavelength of the combining port to the first beam splitter. The method is simple and practical, and has high operability. It should be noted that, when the multiplex port is the access end of the OTDR, the transmission wavelength and the reception wavelength of the multiplexer may be the same. Preferably, the second single-fiber bidirectional optical fiber is a primary optical fiber. For example, the multiplexed wave splitting module 66 is connected to the service port through the main kilofiber. When transmitting, the optical signal transmitted in the main tens of optical fiber is synthesized by the multiplexed wave splitting module 66, including the optical signal in the transmitting optical module 62 and passed through. The first single-fiber bidirectional optical fiber is connected to the optical signal of the multiplexed port; when receiving, the multiplexed wave splitting module 66 transmits the optical signal transmitted in the primary optical fiber to the corresponding receiving optical module 64 according to the wavelength thereof. The multiplexer port of the first single-fiber bidirectional fiber connection. According to an embodiment of the present invention, a PON is also provided. FIG. 7 is a structural block diagram of a PON according to an embodiment of the present invention. As shown in FIG. 7, the PON includes an OTDR 72 and the foregoing OLT, where The optical module 60 includes: a transmitting optical module 62, a receiving optical module 64, and a multiplexed wave splitting module 66, wherein the multiplexed wave splitting module 66 is connected to the access end of the OTDR 72 through the first single-fiber bidirectional optical fiber (ie, The multiplex port is the access end of the OTDR 72;), and is connected to the service port of the PON through the second single-fiber bidirectional optical fiber, and is configured to combine the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module 62 to be sent to the first Two single-fiber bidirectional optical fibers; and optical signals from the second single-fiber bidirectional optical fibers are respectively transmitted according to their wavelengths to corresponding receiving optical modules 64 or first single-fiber bidirectional optical fibers. Corresponding to the above OLT, the implementation of the present invention also provides a method for transmitting an optical signal. FIG. 8 is a flowchart of a method for transmitting an optical signal according to an embodiment of the present invention. The method includes the following steps: Step S802, a block of a multiplexed wave splitting mode 66 in an optical module 60 of an OLT will be from a first single-fiber bidirectional optical fiber and light. The optical signals of the transmitting optical module 62 in the module are combined and sent to the second single-fiber bidirectional optical fiber; and in step S804, the multiplexed-wavelength separating module 66 transmits the optical signals from the second single-fiber bidirectional optical fiber to their respective wavelengths. The receiving optical module 64 or the first single-fiber bidirectional optical fiber in the optical module; wherein the multiplexed wave splitting module 66 is connected to the multiplexed port through the first single-fiber bidirectional optical fiber, and is connected to the service port through the second single-fiber bidirectional optical fiber. Through the above steps, the method of adding a single-fiber bidirectional multiplexer port and a multiplexed wave splitting module 66 in the optical module 60 of the OLT solves the related art in that the multiplexed demultiplexer is set on the OLT. Therefore, the optical fiber between the OLT and the multiplexed wave splitter is prone to failure, which causes the OTDR to detect the problem of the returned optical signal, which saves the network device and maintenance cost, and improves the performance of the system. Preferably, the multiplexer/demultiplexing module 66 is included in the single-fiber bidirectional optical component BOSA of the optical module 60, wherein the multiplexed-wavelength-dividing module 66 includes a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of the following: The transmission wavelength of the wave port (that is, the first single-fiber bidirectional optical fiber is connected to the multiplexed wave splitting module 66), the receiving wavelength of the multiplexing port, the wavelength of the transmitting optical module 62 for transmitting the optical signal, and the receiving optical module 64 for receiving the optical signal. wavelength. In the implementation, the beam splitter may include a first beam splitter and a second beam splitter. In step S802, the first beam splitter may totally reflect the light signal from the first single-fiber bidirectional fiber to the second beam splitter, and second The optical splitter can totally reflect the received optical signal from the first splitter to the second single-fiber bidirectional optical fiber; and the second splitter can transparently transmit the optical signal sent by the transmit optical module 62 to the second single-fiber bidirectional optical fiber. In step S804, the second beam splitter may transparently transmit the optical signal from the optical signal of the second single-fiber bidirectional optical fiber to the wavelength of the optical signal received by the receiving optical module 64 to the receiving optical module 64. The optical signal matching the receiving wavelength of the multiplex port in the optical signal of the second single-fiber bidirectional optical fiber is totally reflected to the first beam splitter; and the first optical splitter can receive the received optical signal from the second splitter Reflected to the first single-fiber bidirectional fiber. The implementation process of the above embodiment will be described in detail below in conjunction with the preferred embodiments and the accompanying drawings. Embodiment 1 This embodiment provides an optical module device with a multiplexer port, which can provide an additional optical interface (hereinafter referred to as a multiplex port), and integrate multiple pairs of optical signals into one optical fiber inside the module. OTDR or other services are convenient. In the related art, the PON optical module can only process a pair of transmitting and receiving optical signals. FIG. 9 is a schematic diagram of an optical module device according to Embodiment 1 of the present invention. As shown in FIG. 9, a fiber optical port is added to the PON optical module as a multiplexer port; and a multiplexer/demultiplexer module is added inside the optical module. The optical multiplexing/demultiplexing of the light of the module 4 and the service port enables the OTDR or other services to be directly connected to the service port inside the optical module, eliminating external optical fibers, optical switches, multiplexer beamsplitters, etc. . Taking the OTDR application as an example, it is assumed that the optical fiber to be detected is the optical fiber of the service port, the OTDR uses the wavelength λι , the upstream wavelength of the PON service (the OLT receiving wavelength) is λ 2 , and the downstream wavelength (the OLT transmission wavelength) is λ 3 . 10 is a schematic diagram of an OTDR application of an optical module device according to the first embodiment of the present invention. As shown in FIG. 10, an OTDR is connected to a multiplex port. When detecting, the OTDR emits an optical signal of a wavelength, such as inside the optical module (for example, The transmitting optical module sends a light signal of wavelength λ 3 to the TOSA. The optical signals of the two wavelengths are combined by the multiplex/split module and sent to the optical fiber of the service port, and the optical signal of the wavelength is the optical fiber of the service port. The transmitted, reflected, and returned optical signals enter the optical module from the service port together with the optical signal of wavelength λ 2 , and are separated from the optical signals of λ 2 by the combining/demultiplexing module, and sent to the OTDR and the optical module respectively. (For example, the receiving optical module is ROSA). Taking the XGPON application as an example, the downlink wavelength of the 10G GPON is λ 4 , the upstream wavelength is λ 5 , the downstream wavelength of the GPON is λ 6 , and the upstream wavelength is λ 7 . 11 is a schematic diagram of an XGPON application of an optical module device according to Embodiment 1 of the present invention. As shown in FIG. 11, when a GPON service is connected to a multiplex port, when transmitting, the GPON service emits an optical signal having a wavelength of λ 6 , and the optical module internally (For example, TOSA) emits an optical signal of wavelength λ 4 , and the optical signals of the two wavelengths are combined by the combining/demultiplexing module and sent to the optical fiber of the XGPON service port; when receiving, the optical signal with the wavelength of λ 5 is The optical signals with the wavelength λ 7 enter the optical module from the XGPON service port, and the optical signals of the two wavelengths are separated by the multiplex/split module and sent to the GPON service port and the optical module (for example, ROSA). It can be seen that the optical module device in this embodiment provides additional service access by adding a single-fiber bidirectional optical interface (ie, a multiplex port;) and adding a multiplexer/demultiplexer module inside the optical module, for example, additional The service can be OTDR access or PON system service. When applied to an OTDR, the l:n switch and the multiplexer/demultiplexer can be omitted, and the problem that the optical fiber between the OLT and the multiplexer/demultiplexer (the optical fiber 1 to the optical fiber n in FIG. 5) cannot be detected is also solved; When applied to the XGPON system, the GPON service can be directly integrated into the 10G GPON service to form the XGPON hybrid service, which makes the peripheral optical interface cabling of the OLT device simple and convenient, and saves maintenance costs. The PON optical module implemented in the "BOS A+ circuit board" mode is taken as an example. In the implementation process, the multiplexer/demultiplexer module can be encapsulated in the BOSA. That is, the existing BOSA structure is improved by adding one lens and two beamsplitters. 12 is a schematic diagram of an optical module device according to a second embodiment of the present invention. As shown in FIG. 12, the beam splitter a totally reflects the light of the multiplexer port to the beam splitter b; the beam splitter b can be selected according to the wavelength, for the service The light of the mouth, the beam splitter b is equivalent to transparency, and the light of the service port is transmitted. For the light of the multiplexer port, the beam splitter b is totally reflected, and the light of the multiplex port is integrated into the optical fiber of the normal service end. FIG. 13 is a schematic diagram of an OTDR application of an optical module device according to Embodiment 2 of the present invention. As shown in FIG. 13, an OTDR is taken as an example to connect an OTDR to a multiplex port, thereby eliminating the 1: switching in the related art. Wave splitter (shown in Figure 5). In this application, the beam splitter a is actually a reflective sheet. The operating wavelength of the OTDR is 1625 nm, the transmission wavelength of the service port is 1490 nm, and the receiving wavelength is 1310 nm. During the detection, the OTDR emits an optical signal of 1625 nm wavelength, enters the BOSA through the lens, and the reflection sheet a totally reflects it to the beam splitter b. The beam splitter b transmits the light of the wavelengths of 1490 nm and 1310 nm, and totally reflects the light of the wavelength of 1625 nm. In the optical fiber (the fiber to be detected) that is sent to the service port, the optical signal of 1625 nm wavelength is transmitted in the optical fiber, and the returned optical signal is sent to the beam splitter b through the lens, totally reflected to the reflection sheet a, and totally reflected to the OTDR again. The analysis is performed to complete a test. When not detecting, the multiplex port can be sealed with a fiber plug, which is no different from the ordinary PON module application. FIG. 14 is a schematic diagram of an XGPON application of an optical module device according to Embodiment 2 of the present invention. As shown in FIG. 14, the XGPON is taken as an example to connect a GPON service to a multiplex port. The operating wavelength of the 10G GPON OLT is: transmission wavelength 1577nm, reception wavelength 1270nm; GPON OLT operating wavelength is: transmission wavelength 1490nm, reception wavelength 1310nm. When the GPON service is connected, the GPON transmits an optical signal of 1490 nm wavelength through the lens, enters the BOSA through the lens, and the spectroscopic sheet a totally reflects it to the beam splitter b. The beam splitter b transmits the light of 1577 nm and 1270 nm wavelength. 1490nm wavelength light The signal is totally reflected and sent to the optical fiber (XGPON access terminal); at the receiving end, the optical signal of 1310 nm wavelength in the optical fiber (XGPON access terminal) is sent to the beam splitter b through the lens, and the beam splitter b totally reflects it to the beam splitter a. The beam splitter a sends it again to the optical fiber (GPON access terminal). In this way, the GPON and 10G GPON services can be mixedly connected in the optical module, and the peripheral multiplexer/demultiplexer and the like are omitted, and the use is convenient. When no GPON service is required, the GPON access terminal can be sealed with a fiber plug, and the XGPON can be used as a general 10G GPON service application. It should be noted that the ideas of the embodiments of the present invention are only described herein from two applications. Of course, other similar applications are also within the scope of the present invention. In summary, according to the embodiment of the present invention, a method of adding a single-fiber bidirectional multiplexer port and a multiplexed wave splitting module in an optical module is used, and the related art is solved between the OLT and the multiplexed demultiplexer. The fiber is prone to failure and the OTDR does not detect the returned optical signal, which saves network equipment and maintenance costs and improves system performance. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

权 利 要 求 书 Claim
1. 一种光线路终端 OLT, 所述 OLT的光模块包括： 发送光模块、 接收光模 块和合波分波模块， 其中， An optical line terminal OLT, the optical module of the OLT includes: a transmitting optical module, a receiving optical module, and a multiplexing and demultiplexing module, where
所述合波分波模块， 通过第一单纤双向光纤与合波口相连， 通过第 二单纤双向光纤与业务口相连， 设置为将来自所述第一单纤双向光纤和 所述发送光模块的光信号合并后发送至所述第二单纤双向光纤； 以及将 来自所述第二单纤双向光纤的光信号 居其波长分别发送至对应的所述 接收光模块或所述第一单纤双向光纤。  The multiplexed wave splitting module is connected to the multiplexer port through the first single-fiber bidirectional optical fiber, and is connected to the service port through the second single-fiber bidirectional optical fiber, and is configured to be from the first single-fiber bidirectional optical fiber and the transmitting light. The optical signals of the module are combined and sent to the second single-fiber bidirectional optical fiber; and the optical signals from the second single-fiber bidirectional optical fiber are respectively sent to the corresponding receiving optical module or the first single Fiber bidirectional fiber.
2. 根据权利要求 1所述的 OLT, 其中， 所述合波口为光时域反射仪 OTDR 的接入端， 所述业务口为无源光网络 PON的业务口。 The OLT according to claim 1, wherein the multiplex port is an access end of an optical time domain reflectometer OTDR, and the service port is a service port of a passive optical network PON.
3. 根据权利要求 1所述的 OLT, 其中， 所述合波口为 GPON接入端， 所述 业务口为 XGPON的业务口。 The OLT according to claim 1, wherein the multiplex port is a GPON access end, and the service port is a service port of the XGPON.
4. 才艮据权利要求 1所述的 OLT, 其中， 所述光模块还包括单纤双向光组件 BOSA, 所述合波分波模块包含于所述 BOSA。 4. The OLT according to claim 1, wherein the optical module further comprises a single-fiber bidirectional optical component BOSA, and the multiplexed wave splitting module is included in the BOSA.
5. 根据权利要求 1所述的 OLT, 其中， 所述合波分波模块包括透镜和分光 片， 所述分光片的波长选择依赖于以下至少之一： 所述合波口的发送波 长、 所述合波口的接收波长、 所述发送光模块发送光信号的波长、 所述 接收光模块接收光信号的波长。 The OLT according to claim 1, wherein the multiplexed wave splitting module comprises a lens and a beam splitter, and the wavelength selection of the beam splitter depends on at least one of: a transmission wavelength of the multiplexer port, The receiving wavelength of the combining port, the wavelength of the optical signal transmitted by the transmitting optical module, and the wavelength of the optical signal received by the receiving optical module.
6. 根据权利要求 5所述的 OLT, 其中， 所述分光片包括第一分光片和第二 分光片， 其中， The OLT according to claim 5, wherein the beam splitter comprises a first beam splitter and a second beam splitter, wherein
所述第一分光片， 设置为将来自所述第一单纤双向光纤的光信号全 反射至所述第二分光片， 以及将接收到的来自所述第二分光片的光信号 全反射至所述第一单纤双向光纤；  The first beam splitter is configured to totally reflect an optical signal from the first single-fiber bidirectional optical fiber to the second beam splitter, and to totally reflect the received optical signal from the second beam splitter to The first single-fiber bidirectional optical fiber;
所述第二分光片， 设置为将来自所述发送光模块的光信号透传至所 述第二单纤双向光纤， 将来自所述第二单纤双向光纤的光信号中与所述 接收光模块接收光信号的波长匹配的光信号透传至所述接收光模块； 以 及将接收到的来自所述第一分光片的光信号全反射至所述第二单纤双向 光纤， 将所述第二单纤双向光纤的光信号中与所述合波口的接收波长匹 配的光信号全反射至所述第一分光片。 The second beam splitter is configured to transparently transmit an optical signal from the transmitting optical module to the second single-fiber bidirectional optical fiber, and to receive the optical signal from the second single-fiber bidirectional optical fiber Transmitting, by the module, a wavelength-matched optical signal of the optical signal to the receiving optical module; and totally reflecting the received optical signal from the first optical splitter to the second single-fiber bidirectional And an optical fiber that totally reflects the optical signal of the optical signal of the second single-fiber bidirectional optical fiber and the receiving wavelength of the combining port to the first beam splitter.
7. 根据权利要求 1至 6中任一项所述的 OLT, 其中， 所述第二单纤双向光 纤为主千光纤。 The OLT according to any one of claims 1 to 6, wherein the second single-fiber bidirectional optical fiber is a primary optical fiber.
8. —种无源光网络*** PON,包括光时域反射仪 OTDR和光线路终端 OLT, 其中， 所述 OLT的光模块包括： 发送光模块、 接收光模块和合波分波模 块， 其中， 8. A passive optical network system PON, comprising an optical time domain reflectometer OTDR and an optical line terminal OLT, wherein the optical module of the OLT comprises: a transmitting optical module, a receiving optical module, and a multiplexed wave splitting module, wherein
所述合波分波模块， 通过第一单纤双向光纤与所述 OTDR的接入端 相连， 通过第二单纤双向光纤与所述 PON的业务口相连，设置为将来自 所述第一单纤双向光纤和所述发送光模块的光信号合并后发送至所述第 二单纤双向光纤； 以及将来自所述第二单纤双向光纤的光信号才艮据其波 长分别发送至对应的所述接收光模块或所述第一单纤双向光纤。  The multiplexed wave splitting module is connected to the access end of the OTDR through the first single-fiber bidirectional optical fiber, and is connected to the service port of the PON through the second single-fiber bidirectional optical fiber, and is configured to be from the first single And combining the optical signals of the fiber bidirectional optical fiber and the transmitting optical module to the second single-fiber bidirectional optical fiber; and transmitting the optical signals from the second single-fiber bidirectional optical fiber to the corresponding one according to the wavelength thereof The receiving optical module or the first single-fiber bidirectional optical fiber.
9. 一种光信号的传输方法， 包括以下步骤： 9. A method of transmitting an optical signal, comprising the steps of:
光线路终端 OLT 的光模块中的合波分波模块将来自第一单纤双向 光纤和所述光模块中的发送光模块的光信号合并后发送至第二单纤双向 光纤； 以及将来自所述第二单纤双向光纤的光信号根据其波长分别发送 至对应的所述光模块中的接收光模块或所述第一单纤双向光纤；  The multiplexed wave splitting module in the optical module of the optical line terminal OLT combines the optical signals from the first single-fiber bidirectional optical fiber and the transmitting optical module in the optical module, and sends the optical signal to the second single-fiber bidirectional optical fiber; The optical signals of the second single-fiber bidirectional optical fiber are respectively sent to the receiving optical module or the first single-fiber bidirectional optical fiber in the corresponding optical module according to the wavelength thereof;
其中 ,所述合波分波模块通过所述第一单纤双向光纤与合波口相连， 通过所述第二单纤双向光纤与业务口相连。  The multiplexed wave splitting module is connected to the multiplex port through the first single-fiber bidirectional optical fiber, and is connected to the service port by the second single-fiber bidirectional optical fiber.
10. 根据权利要求 9所述的方法， 其中， 所述合波分波模块包含于所述光模 块的单纤双向光组件 BOSA中， 其中， 所述合波分波模块包括透镜和分 光片， 所述分光片的波长选择依赖于以下至少之一： 所述合波口的发送 波长、 所述合波口的接收波长、 所述发送光模块发送光信号的波长、 所 述接收光模块接收光信号的波长。 The method according to claim 9, wherein the multiplexed wave splitting module is included in a single-fiber bidirectional optical component BOSA of the optical module, wherein the multiplexed wave splitting module comprises a lens and a beam splitter. The wavelength selection of the beam splitter depends on at least one of: a transmission wavelength of the multiplexer port, a reception wavelength of the multiplexer port, a wavelength of the optical signal transmitted by the transmitting optical module, and a light received by the receiving optical module. The wavelength of the signal.
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