WO2015127780A1

WO2015127780A1 - Otn system and method for supporting single-fiber bidirectional transmission of supervisory channel light

Info

Publication number: WO2015127780A1
Application number: PCT/CN2014/087159
Authority: WO
Inventors: 梅亮; 李健源; 曹云; 刘中华; 廖原; 柴焦
Original assignee: 烽火通信科技股份有限公司
Priority date: 2014-02-25
Filing date: 2014-09-23
Publication date: 2015-09-03
Also published as: CN103840906B; RU2642473C1; CN103840906A; MY176928A

Abstract

Disclosed are an OTN (Optical Transport Network) system and method for supporting single-fiber bidirectional transmission of supervisory channel light, which relate to the field of OTN networks. The system comprises an upstream site and a downstream site. Two optical amplification units and one optical supervisory channel unit are disposed in each site, each site further comprises a combining and splitting unit comprising an optical circulator and a combining and splitting device, an output of the optical supervisory channel unit is connected to an upper port light path of the optical circulator, and a common port of the optical circulator is connected to a light path of the combining and splitting device, and a lower port of the optical circulator is connected to an input light path of the optical supervisory channel unit; the combining and splitting devices of the two sites are connected through two optical fibers, wherein one of which comprises supervisory channel light and forward traffic light transmitted in a bidirectional way and the other comprises backward traffic light. In the present invention, an out-of-band mode is adopted for the transmission of IEEE1588V2 protocol messages to enable transmission and reception of light with the wavelength of the supervisory channel light in one optical fiber, thus avoiding the asymmetry between transmission and reception paths and guaranteeing the consistency of transmission and reception delays.

Description

OTN system and method for supporting monitoring channel optical single fiber bidirectional transmission

Technical field

The present invention relates to the field of OTN networks, and in particular to an OTN system and method for supporting bidirectional transmission of optical single-fiber transmission channels.

Background technique

As the modern mobile communication service bearer network, the optical network transmission equipment can also realize the ground transmission of time synchronization information through the bearer of the IEEE1588V2 protocol, and transmit the time synchronization information from the ground bearer equipment to each base station to achieve high-precision time synchronization. . With the popularity of mobile Internet applications, the demand for bandwidth has shown rapid growth. An OTN (Optical Transport Network) network with multiple wavelengths and large capacity and electrical cross-scheduling flexibility is gradually sinking to the aggregation or access level. The transmission of IEEE1588V2 in OTN networks is also increasingly used.

Because the IEEE1588V2 implements the mechanism of time synchronization, the delay of transmitting IEEE1588V2 packets on the transmission and reception path is symmetric. The traditional OTN network is generally a dual-fiber bidirectional network structure, and the service optical and monitoring channels in the same direction. In the same optical fiber, most bearer services are not symmetrically required for transmission and reception delay symmetry. Therefore, there may be an increase in the delay in the transmission and reception path between the OTM sites of the OTN network (there may be multiple simple optical amplification stations in the middle). Although the asymmetry difference can be compensated after being measured and set to the processing unit of IEEE1588V2, the extensive engineering and the complexity of the test make this method engineering difficult to promote.

The bearer mode of IEEE1588V2 in OTN network equipment mainly has in-band (service Optical transmission) and out-of-band (monitoring channel optical transmission). Since the in-band mode is carried by the service optical wavelength, and the service optical wavelength adopts different optical fibers on the transmission path, there is a problem that the transmission and reception delay is asymmetric, and it also appears in the process of mapping and multiplexing of services and joining FEC. Delayed changes.

Summary of the invention

In view of the deficiencies in the prior art, an object of the present invention is to provide an OTN system and method for supporting bidirectional transmission of a single optical fiber of a monitoring channel, which uses an outband transmission method to transmit the basis of the IEEE 1588 V2, so that the optical transmission and reception of the optical wavelength of the monitoring channel is performed. In an optical fiber, the asymmetry of the transmission and reception paths is avoided, and the delay of transmission and reception is ensured.

To achieve the above objective, the present invention provides an OTN system supporting bidirectional transmission of a single optical fiber of a monitoring channel, including an upstream station and a downstream station that mutually transmit service light, each of which is provided with two optical amplifying units and one optical monitoring unit. Channel unit, each station further comprises a multiplexer unit, the multiplexer unit comprises an optical circulator and a multiplexer, and the output of the optical monitoring channel unit is connected to the optical path of the optical circulator, and the optical circulator is common The port is connected to the optical path of the multiplexer, and the lower port of the optical circulator is connected to the input optical path of the optical monitoring channel unit; the multiplexer and the splitter of the two stations are connected by two optical fibers, and one optical fiber includes bidirectional transmission monitoring. Channel light and forward traffic light, and the other fiber contains reverse traffic light.

On the basis of the foregoing technical solutions, the two optical amplifying units of the upstream station are divided into a forward transmitting amplifying unit that transmits forward traffic light, and a reverse receiving amplifying unit that receives reverse traffic light, and a forward transmitting amplifying unit. Connected to the splitter optical path of the upstream site; the two optical amplifying units of the downstream site are divided into a forward receiving amplifying unit that receives forward traffic light, and a reverse transmitting amplifying unit that transmits reverse traffic light, The receiving amplifying unit is connected to the splitter optical path of the downstream station.

The present invention also provides a method for supporting bidirectional transmission of optical single-fiber transmission of a monitoring channel based on the above system, and the forward traffic light is amplified and then enters the upstream station and the split-wave unit, and passes through the station. The two-way monitoring channel of the point-light circulator is combined and transmitted to a downstream station through a fiber; the service light transmitted to the downstream station is separated by the multiplexer unit of the station, and output to the station and connected to the multiplexer and the splitter. An optical amplifying unit, the bidirectional monitoring channel light is separated by the optical circulator by two different directions of light, and the optical paths are respectively connected to the input port and the output port of the optical monitoring channel unit of the station; the upstream station receives the slave station from the downstream station in the same manner Business light.

On the basis of the foregoing technical solution, the reverse service light is amplified by an optical amplifying unit that is not connected to the multiplexer/demultiplexer in the downstream station, and then transmitted to an optical amplifying unit of the upstream station through a single optical fiber, and The optical amplifying unit is not connected to the combiner and the splitter of the station.

The present invention further provides an OTN system for supporting bi-directional transmission of optical single-fiber transmission of a channel, comprising an upstream station and a downstream station for transmitting service light to each other, each of which is provided with two optical amplifying units and one optical monitoring channel unit. Each station further includes an optical line protection unit, and the optical line protection unit is provided with a multiplexer unit, and the multiplexer unit includes an optical circulator and a multiplexer, an output of the optical monitoring channel unit and an optical path on the optical circulator. Connected, the common port of the optical circulator is connected to the optical path of the multiplexer, and the lower port of the optical circulator is connected to the input optical path of the optical monitoring channel unit; the multiplexer of the upstream station is connected to a coupler, the downstream station The multiplexer and splitter are connected to an optical switch, and the coupler and the optical switch are connected by a main line fiber and a spare line fiber.

On the basis of the foregoing technical solutions, the two optical amplifying units of the upstream station are divided into a forward transmitting amplifying unit that transmits forward traffic light, and a reverse receiving amplifying unit that receives reverse traffic light, and a forward transmitting amplifying unit. Connected to the optical splitter optical path of the station; the two optical amplifying units of the downstream station are divided into a forward receiving amplifying unit that receives forward traffic light, and a reverse transmitting amplifying unit that transmits reverse traffic light, The receiving amplifying unit is connected to the optical path of the multiplexer and the splitter of the station.

Based on the above technical solution, the upstream station further includes an optical switch, and the reverse receiving amplifying unit is connected to the optical switch optical path; the downstream station further includes a coupler, and the reverse transmitting amplifying unit of the downstream station The coupler optical path of the station is connected; the optical switch of the upstream station and the coupler of the downstream station are connected by the main and standby line fibers.

Based on the above technical solution, the optical switch is a 2×2 optical switch, the coupler is a 1:2 coupler, and the optical switch is further connected to an optical power detector.

The invention also provides a method for supporting bidirectional transmission of optical single-fiber transmission of a monitoring channel based on the system, wherein the forward service light is combined with the bidirectional monitoring channel light passing through the circulator through the multiplexer and the output is coupled to the optical coupling. The device is distributed to the forward main and standby line fibers; at the downstream station, the optical switch is connected to an optical power detector, and the main and standby line lights are selected by the optical switch, and then connected to the optical power detector and connected to the same. The splitter splits the service light from the monitor channel light, and the separated service light is output to the optical amplifying unit of the station, and the separated monitor channel light is connected to the optical monitoring channel unit of the station via the optical path of the circulator; The upstream site receives the traffic light from the downstream site in the same manner.

Based on the above technical solution, the upstream station further includes an optical switch, the reverse receiving amplifying unit is connected to the optical switch optical path, and the optical switch is further connected to an optical power detector; the downstream station further includes a coupler The reverse transmission amplifying unit of the downstream station is connected to the coupler optical path of the station; the optical switch of the upstream station and the coupler of the downstream station are connected by the main and standby line optical fibers, and the reverse direction service light is amplified. The optocoupler entering the downstream site is distributed to the main and standby fiber optic lines in the opposite direction. After reaching the upstream site, the optical switch is selected by the station, and one service light enters the optical power detector of the station, and the optical amplifying unit is output to the station. .

The invention has the beneficial effects that the IEEE1588V2 is transmitted by using the optical monitoring channel that does not carry the service signal, and there is no delay variation introduced in the bearer mode. Through the traditional The optical circulator is set up in the OTN network to make it a single-fiber bidirectional transmission mode, thereby avoiding the asymmetry of the service transmission and reception path and having no influence on the window wavelength of the bearer service.

DRAWINGS

1 is an optical path diagram of a single-fiber bidirectional OTN system with symmetric service transmission and reception paths according to a first embodiment of the present invention;

2 is a schematic diagram of a multiplexer unit of an upstream station in a first embodiment of the present invention;

3 is an optical path diagram of a single-fiber bidirectional OTN system with symmetric service transmission and reception paths according to a second embodiment of the present invention;

Figure 4 is a system light path diagram of the more detailed structure of Figure 3.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

First embodiment:

As shown in FIG. 1 and FIG. 2, an OTN system supporting monitoring channel optical single-fiber bidirectional transmission includes an upstream station and a downstream station that transmit service light to each other, and each station has two OAs (optical amplifiers). And an optical supervisory channel unit (OSC), each station further comprising a multiplexer unit (OSC AD), the multiplexer unit comprising an optical circulator and a multiplexer. The output of the optical monitoring channel unit is connected to the optical path of the optical port on the optical circulator. The common port of the optical circulator is connected to the optical path of the multiplexer, and the lower optical port of the optical circulator is connected to the input optical path of the optical monitoring channel unit. The two OAs of the upstream site are divided into a forward transmitting OA that transmits forward traffic light, and a reverse receiving OA that receives reverse traffic light, and the forward transmitting OA is connected to the optical splitter optical path of the upstream site. The two OAs of the downstream station are divided into a forward receiving OA that receives the forward traffic light, and a reverse transmitting OA that sends the reverse traffic light, and the forward receiving optical path of the OA and the downstream station. Connected. The multiplexer and splitter of the two stations are connected by two optical fibers, one of which contains bidirectionally transmitted monitoring channel light and forward traffic light, and the other fiber contains reverse traffic light. In this embodiment, the service light is 1550 nm window wavelength light, and the optical monitoring channel light of the optical monitoring channel unit is 1510 nm wavelength light.

The invention supports the method for monitoring the channel optical single-fiber bidirectional transmission. After the forward service light is amplified by the forward transmission OA, it enters the upstream site multiplexer unit, and merges with the bidirectional monitoring channel light passing through the optical circulator of the station. A fiber is sent to the downstream site. At the downstream site, the service light transmitted to the downstream site is separated by the multiplexing and splitting unit of the station, and is output to the forward receiving OA of the station, and the bidirectional monitoring channel light is separated by the optical circulator by two different directions of light. They are respectively connected to the input port and the output port of the optical monitoring channel unit of the station. Since the service light is transmitted in the same way between the upstream site and the downstream site, only in the opposite direction, the downstream site sends traffic light to the upstream site in the same manner, and the upstream site receives the service light from the downstream site in the same manner.

In this embodiment, the reception and transmission of the 1510nm wavelength service light are all in the same fiber, and the IEEE1588V2 is completely in the same path, so that there is no asymmetry in the transmission and transmission, and the upstream and downstream sites are ensured. Time synchronization between the two, can also have high precision without compensation.

Second embodiment:

As shown in FIG. 3 and FIG. 4, in the embodiment, the OTN system supporting the monitoring channel optical single-fiber bidirectional transmission adopts a 1+1 protection mode, that is, concurrent selection. This embodiment also includes an upstream station and a downstream station that transmit service light to each other. Each station is internally provided with two OAs and one optical monitoring channel unit, and each station further includes an optical line protection unit (OLP, Optical Fiber Line Auto). Switch Protection Equipment), the optical line protection unit is provided with an multiplexer unit (OSC AD), and the multiplexer unit includes an optical circulator and a multiplexer, and the output of the optical monitoring channel unit is connected to the optical path of the optical port on the optical circulator. Light circulator The port is connected to the optical path of the multiplexer, and the lower port of the optical circulator is connected to the input optical path of the optical monitoring channel unit; the multiplexer of the upstream station is connected to a coupler, and the multiplexer and the optical path of the downstream station are connected. An optical switch, the coupler and the optical switch are connected by a main line fiber and a spare line fiber.

The two optical OAs of the upstream station are divided into a forward transmission OA that transmits forward traffic light, and a reverse reception OA that receives reverse traffic light, and the forward transmission OA is connected to the optical splitter optical path of the station. The two OAs of the downstream station are divided into a forward receiving OA that receives forward traffic light and a reverse transmitting OA that transmits reverse traffic light, and the forward receiving OA is connected to the optical splitter optical path of the station.

The upstream site further includes an optical switch, the reverse receiving OA is connected to the optical switch optical path; the downstream station further includes a coupler, and the reverse transmitting OA of the downstream station is connected to the coupler optical path of the station; The optical switch of the upstream site and the coupler of the downstream site are connected by the main and standby line fibers. In this embodiment, the optical switch is a 2×2 optical switch controlled by a CPU (not shown) in the optical line protection unit, and each optical switch is connected to an optical power detector, and the coupler is 1: 2 Coupler, the service light is 1550 nm window wavelength light, and the light monitoring channel light is 1510 nm wavelength light.

In this embodiment, the method for supporting the monitoring channel optical fiber single-fiber bidirectional transmission is: after the forward service light is amplified by the forward transmission OA at the upstream station, and the bidirectional monitoring channel light passing through the station circulator is merged by the multiplexer and the splitter. Incorporate a fiber and output it to the optocoupler for 50:50 splitting and distribution to the forward main and standby line fibers. At the downstream site, after the primary and backup line lights are selected by the optical switch, the unselected one-way light is connected to the optical power detector; the selected one-way optical is connected to the combined splitter to separate the service light from the monitoring channel light, and separated. The business light is output to the optical amplifying unit of the station, and is amplified and output. After the separated monitoring channel lights are separated by the circulator, they are respectively sent to the light collecting port and the illuminating port of the optical monitoring channel unit of the station. Since the way to send service light between the upstream site and the downstream site is the same, it is only a square To the contrary, the downstream station sends traffic light to the upstream site in the same manner, and the upstream site receives traffic light from the downstream site in the same manner.

The reverse direction service light is amplified by the reverse transmission OA at the downstream station, and then enters the optical line protection unit of the downstream station, and after being split by the 50:50 optical coupler, it is sent to the upstream station through the primary and backup optical fiber lines. After reaching the upstream site, the optical switch is selected by the station, and one service light is selected to be amplified by the reverse receiving OA and output to other units, and the other service light enters the optical power detector of the station.

The primary and backup line fibers from the upstream site to the downstream site contain 1550 nm service light and 1510 nm monitoring channel light of the two-site protection method, and carry IEEE1588V2 on the 1510 nm wavelength monitoring channel. Among the primary and backup line fibers from the downstream site to the upstream site, only the 1550 nm wavelength optical optical line protection unit (OLP) determines the quality of the optical fiber line based on the optical power performance and completes the switching operation, and also ensures the transmission and reception of 1510 nm wavelength light. Performed in the same fiber.

The present invention is not limited to the above embodiments, and those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. These improvements and retouchings are also considered as protection of the present invention. Within the scope. The contents not described in detail in the present specification belong to the prior art well known to those skilled in the art.

Claims

An OTN system supporting monitoring channel optical single-fiber bidirectional transmission includes an upstream station and a downstream station that transmit service light to each other, and each station is provided with two optical amplifying units and one optical monitoring channel unit, which are characterized in that: The station further includes a multiplexer unit including an optical circulator and a multiplexer, the output of the optical monitoring channel unit being connected to the optical path of the optical circulator, the common port of the optical circulator and the The splitter optical path is connected, and the optical port of the optical circulator is connected to the input optical path of the optical monitoring channel unit; the multiplexer and the splitter of the two stations are connected by two optical fibers, and one optical fiber includes the bidirectional transmission of the monitoring channel light and the forward direction. Service light, another fiber contains reverse traffic light.
The OTN system for supporting monitoring channel optical single-fiber bidirectional transmission according to claim 1, wherein: the two optical amplifying units of the upstream station are divided into a forward transmission amplifying unit that transmits forward traffic light, and receives a reverse a reverse receiving amplifying unit to the service light, wherein the forward transmitting amplifying unit is connected to the optical splitter optical path of the upstream station; the two optical amplifying units of the downstream station are divided into a forward receiving amplifying unit that receives the forward service light, And a reverse transmission amplifying unit that transmits the reverse service light, and the forward receiving amplifying unit is connected to the optical path of the combining and splitting device of the downstream station.
A method for supporting monitoring channel optical single-fiber bidirectional transmission according to the system of claim 1 is characterized in that: the forward service light is amplified and then enters the upstream site multiplexer unit, and the two-way monitoring of the optical circulator through the station After the channel light is combined, it is sent to the downstream station through an optical fiber; the service light transmitted to the downstream site is separated by the multiplexer unit of the station, and output to an optical amplifying unit connected to the multiplexer and the splitter at the station, bidirectional The monitoring channel light is separated by the optical circulator by two different directions of light, and the optical paths are respectively connected to the input port and the output port of the optical monitoring channel unit of the station; the upstream station receives the service light from the downstream station in the same manner.
A method for supporting bidirectional transmission of optical single-fiber transmission of a monitoring channel according to claim 3. The method is characterized in that: the reverse service light is amplified by an optical amplifying unit that is not connected to the multiplexer/demultiplexer in a downstream station, and then transmitted to an optical amplifying unit of the upstream station through a single optical fiber, and the light is output. The amplification unit is not connected to the multiplexer and splitter of the station.
An OTN system supporting monitoring channel optical single-fiber bidirectional transmission includes an upstream station and a downstream station that transmit service light to each other, and each station is provided with two optical amplifying units and one optical monitoring channel unit, which are characterized in that: The stations further comprise an optical line protection unit, the optical line protection unit is provided with a multiplexer unit, and the multiplexer unit comprises an optical circulator and a multiplexer, and the output of the optical monitoring channel unit is connected to the optical path of the optical circulator. The common port of the optical circulator is connected to the optical path of the multiplexer, and the lower port of the optical circulator is connected to the input optical path of the optical monitoring channel unit; the multiplexer of the upstream station is connected to a coupler, the downstream station The combiner and splitter are connected to an optical switch, and the coupler and the optical switch are connected by a main line fiber and a spare line fiber.
The OTN system for supporting monitoring channel optical single-fiber bidirectional transmission according to claim 5, wherein: the two optical amplifying units of the upstream station are divided into a forward transmitting amplifying unit that transmits forward traffic light, and the receiving reverse a reverse receiving amplifying unit for the service light, the forward transmitting amplifying unit is connected to the multiplexer optical path of the station; the two optical amplifying units of the downstream station are divided into a forward receiving amplifying unit that receives the forward service light, And a reverse transmission amplifying unit that transmits the reverse service light, and the forward receiving amplifying unit is connected to the optical path of the combining and splitting device of the station.
The OTN system for supporting monitoring channel optical single-fiber bidirectional transmission according to claim 6, wherein the upstream station further comprises an optical switch, and the reverse receiving amplifying unit is connected to the optical switch optical path; the downstream station A coupler is further included, and the reverse transmission amplifying unit of the downstream station is connected to the coupler optical path of the station; the optical switch of the upstream station and the coupler of the downstream station are connected by the main and standby line fibers.
Supporting monitoring channel optical single-fiber bidirectional transmission according to claim 5, 6 or 7 The OTN system is characterized in that: the optical switch is a 2×2 optical switch, the coupler is a 1:2 coupler, and the optical switch is also connected to an optical power detector.
A method for supporting monitoring channel optical single-fiber bidirectional transmission according to the system of claim 5, characterized in that: after the forward service light is amplified, the bidirectional monitoring channel light passing through the circulator is combined by the multiplexer and the output, and then output To the optocoupler, distributed to the forward main and standby line fibers; at the downstream site, the optical switch is connected to an optical power detector, the main and standby line lights are selected by the optical switch, and all the way to the optical power detector, all the way Receiving the splitter and separating the service light from the monitoring channel light, the separated service light is output to the optical amplifying unit of the station, and the separated monitoring channel light is connected to the optical monitoring channel unit of the station through the optical path of the circulator The upstream site receives traffic light from the downstream site in the same manner.
A method for supporting bi-directional transmission of optical single-fiber in a monitoring channel according to claim 9, wherein the upstream station further comprises an optical switch, and the reverse receiving and amplifying unit is connected to the optical switch optical path, and the optical switch is further Connecting an optical power detector; the downstream station further includes a coupler, the reverse transmitting amplifying unit of the downstream station is connected to the coupler optical path of the station; and the optical switch of the upstream station and the coupler of the downstream station pass between The main and standby line fiber connections are connected, and the optocoupler that enters the downstream site is amplified and then distributed to the main and standby fiber optic lines in the opposite direction. After reaching the upstream site, the optical switch is selected by the station, and one service light enters. The site optical power detector is output to the optical amplifying unit of the station.