KR100768623B1 - Optical line obstacle recovery system using only one reserve optical signal in passive optic network - Google Patents

Abstract

A system for automatically recovering a fault of an optical line by using a reserved optical signal in a PON(Passive Optical Network) is provided to enhance utilization of resources, reduce an initial investment cost, and continuously provide a quality stable communication service. A reserved light generating unit(10) generates a reserved light signal, combines it with operation light signals and outputs them. A remote node(20) splits the combined reserved light signal and the operation light signals by wavelength and outputs them. A reserved light distributing unit(30) bypasses the wavelength-split optical light signals to a corresponding subscriber split operation optical line and sequentially distributes and outputs the wavelength-split reserved light signal to every subscriber split reserved optical line. A light signal switching unit(40) selectively switches a transmission line of the operation light signals and the reserved light signal according to a switching signal A reflection mirror(50) reflects an applied light signal and outputs it. A switching controller(60) measures the strength of the optical light signals and selectively activates the switching signal according to the size of the measured value.

Description

Optical line obstacle recovery system using only one reserve optical signal in passive optic network}

1 is a block diagram showing a configuration of a general wavelength division multiplexing passive optical subscriber network.

2 is a block diagram showing the configuration of a disaster recovery system according to the present invention.

FIG. 3 is a diagram illustrating in more detail the configuration of the optical signal rotating unit constituting the preliminary light distribution unit in FIG. 2. FIG.

4 is a configuration diagram showing in more detail the configuration of the optical signal switching unit in FIG.

FIG. 5 is a diagram illustrating the configuration of a transfer control unit in FIG. 2 in more detail. FIG.

* Explanation of symbols for the main parts of the drawings

10: reserve light generator 12: reserve light source

14: optical coupling unit 20: remote node

30: preliminary light distribution unit 40: optical signal switching unit

50: reflector 60: switching control

The present invention relates to a system for recovering the optical path failure in a wavelength division multiplexing passive optical subscriber network, and more particularly, by providing an optical switch and an optical reflector in the subscriber's premises, without having to secure an independent spare wavelength for each subscriber. The present invention relates to a system capable of automatically recovering from a failure of all subscriber branch lines with only one preliminary wavelength.

Due to the rapid development of optical communication technology, the fixed-line communication environment of subscribers is changing in two aspects.

First of all, FTTH (Fiber To The Home) based optical subscriber network is being constructed in which subscriber's home communication infrastructure connects optical cables from the telephone company to each home rather than the existing telephone line or coaxial cable.

Second, the wavelength division multiplexing technique used for long-distance high-capacity transmission has been gradually expanded to the subscriber network area, and a device and method for a wavelength division multiple passive optical subscriber network capable of supporting a bandwidth of 100 Mbps to Gbps per household were proposed and proposed. Commercially available devices using conventional techniques are also emerging.

1 is a block diagram showing the configuration of a general wavelength division multiplexing passive optical subscriber network.

1 is a remote node (RN) consisting of an optical line terminal (OLT) 1, an optical network unit (ONU) 2, a broadband light source 3, a wavelength branching / combining element ( 4) and subscriber branch optical path (5).

Wavelength Division Multiplexing Passive optical subscriber network has a 1: N structure in which one N-subscriber shares one optical fiber like other passive optical subscriber networks, but an independent wavelength (communication channel) between the OLT (1) and each ONU (2) ) Is allocated one by one, so it can logically establish 1: 1 communication and provide large bandwidth. In particular, a wavelength division multiplexing passive optical subscriber network using a shared light source is provided via a subscriber branch optical line (5) after an incoherent broadband light source (3) located at an OLT (1) is spectrally divided by a remote node (4). The wavelength of the upstream signal is injected into the light source of the ONU 2 located in the home, and is determined by the wavelength of the remote node 4. That is, since the wavelength of the ONU 2 is determined by the wavelength division multiplexing / demultiplexing element of the remote node 4, there is no need to manage the wavelength and a shared light source has the advantage of lowering the cost of the light source. It is becoming.

However, unlike coaxial, the optical cable installed to each home has a problem that is easily prone to failure such as optical loss and optical cable cutting due to physical bending.

In wavelength division multiplexing (WDM) -based passive optical subscriber networks, optical cables from the remote node (RN) to each home can be easily damaged by wire or subscriber premises by other operators or utilities. Immediate circuit changeover is required when this occurs. In particular, the speed of several Gbps per optical core is delivered directly to the subscriber terminal, and in order to deliver high-quality video services such as IP-TV without interruption, it is necessary to protect against failure. However, in the related art, there is a difficulty in utilizing limited resources by securing a separate spare wavelength for each subscriber for circuit switching.

In addition, when there is no guarantee of the survivability of passive optical subscriber network, if there is an optical cable accident from the optical distribution area to the subscriber's premises, an employee is dispatched to the site and one person goes directly to the periphery of the communication and the other is in the subscriber's premises. A visit should be made to mutually measure the optical power or use an Optical Time Domain Reflectometer (OTDR) to determine the safety of the optical cable. However, in this case, there may be a difficulty in setting an appointment with a customer and a safety problem.

Accordingly, an object of the present invention for solving the above problems is to improve the method of overcoming obstacles to optical paths to automatically detect failures and to automatically overcome failures without collision of field personnel by using only one spare optical signal when a failure occurs. To make it possible.

Automatic optical path failure recovery system using a preliminary optical signal of the present invention for achieving the above object is a preliminary light generating unit for generating a preliminary optical signal and combined with the operating optical signals; A remote node for dividing the preliminary optical signal and the operational optical signal by wavelength for output; A preliminary light distribution unit for bypassing the wavelength-divided operating optical signal to a corresponding subscriber branch operating optical path, and sequentially distributing the wavelength-divided preliminary optical signal to all subscriber-split spare optical paths; An optical signal switching unit for selectively switching a transmission path of an operational optical signal applied through the subscriber branch operating optical path and a spare optical signal applied through the subscriber branch auxiliary optical beam according to a switching signal; A reflector for reflecting and outputting an optical signal provided at an output terminal of the optical signal switching unit; And a switching control unit for measuring the intensity of the operational optical signal and selectively activating the switching signal according to the magnitude of the measured value.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a block diagram showing the configuration of a disaster recovery system according to the present invention.

The disaster recovery system of the present invention includes a preliminary light generator 10, a remote node 20, a preliminary light distributor 30, an optical signal switching unit 40, a reflector 50, and a switching controller 60. .

)과 서로 다른 파장(

)을 갖는 하나의 예비용 광신호를 발생시킨 후 이를 OLT(1)로부터 다중화되어 전송되는 운용 광신호들과 결합시켜 출력한다. 이러한 예비광 생성부(10)는 예비용 광신호를 생성하여 출력하는 예비광원(12) 및 예비광원(12)의 예비용 광신호를 운용 광신호와 결합시키는 광결합부(14)를 구비한다.The preliminary light generation unit 10 may use wavelengths of an operation optical signal for transmission of operation data.

) And different wavelengths (

After generating a spare optical signal having a) and outputs it combined with the operating optical signals that are multiplexed and transmitted from the OLT (1). The preliminary light generating unit 10 includes a preliminary light source 12 for generating and outputting a preliminary light signal and an optical coupling unit 14 for coupling the preliminary light signal of the preliminary light source 12 with the operational light signal. .

The remote node 20 is located above the communication room or telephone pole of the apartment, and splits the downlink signal in which wavelengths of the operational optical signal and the preliminary optical signal are multiplexed for each wavelength to output to the preliminary light distribution unit 30, and the preliminary light distribution unit. The upstream signal from 30 is multiplexed and transmitted to the OLT 1.

)은 대응되는 가입자 분기 운용 광선로(Lm)로 각각 바이패스시켜 출력하고, 예비용 광신호(

)는 순차적으로 회전시켜 각 가입자 댁내의 광신호 스위칭부(40)로 순차적으로 분배시켜 출력한다. 즉, 각 가입자 분기 운용 광선로(Lm)로는 일대일 대응되는 운용 광신호(

)가 전송되는 반면에, 모든 가입자 분기 예비 광선로(Ls)로는 예비광 분배부(30)에 의해 하나의 예비용 광신호(

)가 순차적으로 분배되어 전송된다. 이러한 예비광 분배부(30)는 각 가입자별로 일대일 대응되게 구비되며 인가되는 예비용 광신호(

)를 일정 방향으로 회전시켜 출력하는 N개(본 실시예에서는 32개)의 광신호 회전부(31 ∼ 34)를 구비한다.The preliminary light distribution unit 30 operates optical signals among the optical signals that are wavelength-differentiated at the remote node 20 (

) Are bypassed to the corresponding subscriber branch operating optical line Lm and outputted, respectively.

) Is sequentially rotated and distributed to the optical signal switching unit 40 in each subscriber's home and output. That is, each subscriber branch operation optical path Lm corresponds to a one-to-one operation optical signal (

On the other hand, all the subscriber branch reserve optical paths Ls are transmitted by the preliminary light distribution unit 30 to one spare optical signal (

) Are sequentially distributed and transmitted. The preliminary light distribution unit 30 is provided in a one-to-one correspondence for each subscriber and the preliminary optical signal (

) Are provided with N optical signal rotating parts 31 to 34 for outputting by rotating in a predetermined direction.

The optical signal switching unit 40 is a 2 × 2 optical switch provided in each subscriber's premises, and an operational optical signal and a spare optical signal respectively received through the subscriber branch operating light beam Lm and the subscriber branch spare optical beam Ls. Is selectively transmitted to the ONU 2 according to the switching signal Ssw. That is, when the switching signal Ssw is inactivated, the optical signal switching unit 40 transmits the operation optical signal received through the subscriber branch operating light path Lm to the ONU 2 and through the subscriber branch backup light path Ls. The preliminary optical signal received is transmitted to the reflector 50. On the other hand, when the switching signal Ssw is activated, the optical signal switching unit 40 switches the transmission path between the operational optical signal and the spare optical signal so that the spare optical signal is transmitted to the ONU 2.

The reflector 50 reflects the applied optical signal and outputs it.

The switching control unit 60 measures the intensity of the operational optical signal and selectively activates the switching signal Ssw according to the intensity.

FIG. 3 is a diagram illustrating in detail the configuration of any one optical signal rotating unit 31 constituting the preliminary light distribution unit 30 in FIG. 2.

Each optical signal rotating unit 31 (nth optical signal rotating unit) includes an optical circulator 35 having three input / output ports "0", "1", and "2". At this time, port "0" is connected to port "2" of the remote node 20 or the neighboring optical signal rotating unit (n-1th optical signal rotating unit), and port "1" is connected to the subscriber branch spare beam ( Ls), and a port "2" is connected to a port "0" of a neighboring optical signal rotating unit (n + 1 th optical signal resetting).

)는 광서큘레이터(35)에 의해 시계방향으로 회전되어 가입자 분기 예비 광선로(Ls)와 연결된 "1"번 포트로 출력된다. "1"번 포트로 출력된 예비용 광신호는 가입자 분기 예비 광선로(Ls)를 따라 진행하다 광신호 스위칭부(40)를 거쳐 반사경(50)에서 반사된 후 다시 "1"번 포트로 되돌아온다. "1"번 포트로 반사되어 되돌아온 예비용 광신호는 다시 광서큘레이터(35)에 의해 회전되어 광신호 회전부(31)의 "2"번 포트를 통해 이웃한 광신호 회전부(n+1 번째)의 "0"번 포트로 인가된다.The operation of the optical signal rotating unit 31 is briefly described as follows. A spare optical signal applied from the remote node 20 or the adjacent optical signal rotating unit (n-1 th optical signal rotating unit) through the port "0" (

) Is rotated clockwise by the optical circulator 35 and outputted to port "1" connected to the subscriber branch reserve optical path Ls. The preliminary optical signal outputted to the port "1" proceeds along the subscriber branch reserve optical path Ls, is reflected by the reflector 50 through the optical signal switching unit 40, and then returns to the port "1" again. come. The preliminary optical signal reflected back to the port "1" is rotated by the optical circulator 35 again and adjacent to the optical signal rotating unit (n + 1 th) through the port "2" of the optical signal rotating unit 31 Is applied to port "0".

4 is a diagram illustrating in detail the configuration of the optical signal switching unit 40 in FIG. 2.

The optical signal switching unit 40 is physically connected to the subscriber branch preliminary optical beam Ls and the subscriber branch operating optical beam Lm, which are physically introduced into the subscriber's premises, and the other is connected to the reflector 50 and the ONU 2. do. The optical signal switching unit 40 is electrically connected to the switching control unit 60 to receive the switching signal Ssw from the switching control unit 60.

In the state in which the switching signal Ssw is inactivated (normal state), the optical signal switching unit 40 divides the reflector 50 and the subscriber branch backup light beam Ls and the subscriber branch operation light beam Lm as shown in the solid line of FIG. 4, respectively. Connect to ONU (2). However, in the state in which the switching signal Ssw is activated (failure state), as shown in the dotted line of FIG. 4, the transmission path is crossed so that the subscriber branch reserve optical path Ls and the subscriber branch operation optical path Lm are ONU, respectively. 2) and the reflecting mirror 50 allow the preliminary optical signal to be applied to the ONU 2.

FIG. 5 is a configuration diagram illustrating the configuration of the transfer control unit 60 in FIG. 2 in more detail.

The transfer control unit 60 includes a light intensity distribution unit 61, a light intensity measurement unit 62, and a switching signal generator 63.

The light intensity distribution unit 61 branches a part of the operating optical signal applied through the corresponding subscriber branch operating light path Lm and outputs the light to the light intensity measuring unit 62.

The light intensity measuring unit 62 measures the intensity of the optical signal branched from the light intensity distribution unit 61 and outputs the measured value to the switching signal generator 63.

The switching signal generator 63 compares the measured value from the light intensity measuring unit 62 with a preset threshold and activates the switching signal Ssw when the measured value is lower than the threshold and outputs the converted signal to the optical signal switching unit 40.

Referring to the operation of the automatic optical path failure recovery system according to the present invention having the above-described configuration is as follows.

)는 광결합기(14)에 의해 OLT(1)로부터 파장분할다중화되어 출력되는 운용 광신호들(

)과 결합되어 원격노드(20)로 전송된다.In the steady state, the reserve optical signal generated by the reserve light source 12 (

) Are optical signals that are multiplexed and output from the OLT 1 by the optical coupler 14.

) Is transmitted to the remote node 20.

,

)을 파장별로 분기시켜 출력한다. 이때, 운용 데이터가 실린 운용 광신호(

)는 각각 일대일 대응되는 가입자 분기 운용 광선로(Lm)로 인가되어 광신호 스위칭부(40)로 전송된다. 반면에, 본원발명의 예비용 광신호(

)는 예비광 분배부(30)에서 첫번째 광신호 회전부(31)의 "0"번 포트로 인가된다. 첫번째 광신호 회전부(31)의 "0"번 포트로 인가된 예비용 광신호는 광서큘레이터(35)에 의해 시계방향으로 회전되어 "1"번 포트로 출력된다. "1"번 포트로 출력된 예비용 광신호는 대응되는 광신호 스위칭부(40)로 전송된다.Remote node 20 is applied to the optical signals (

,

) Is output by dividing by wavelength. At this time, the operation light signal containing the operation data (

) Is applied to the subscriber branch operation light beam Lm corresponding to each other one-to-one and transmitted to the optical signal switching unit 40. On the other hand, the spare optical signal of the present invention (

) Is applied from the preliminary light distribution unit 30 to the port "0" of the first optical signal rotating unit 31. The preliminary optical signal applied to the port "0" of the first optical signal rotating unit 31 is rotated clockwise by the optical circulator 35 and outputted to the port "1". The preliminary optical signal output to the port "1" is transmitted to the corresponding optical signal switching unit 40.

The operational optical signal and the spare optical signal applied to the optical signal switching unit 40 are applied to the ONU 2 and the reflecting mirror 50 by the optical signal switching unit 40, respectively. That is, since the switching signal Ssw is not activated in the normal state in which no obstacle occurs, the optical signal switching unit 40 switches the operational optical signal and the spare optical signal to the ONU 2 and the reflector 50 without switching the transmission paths, respectively. Bypass

At this time, the preliminary optical signal transmitted to the reflector 50 is reflected by the reflector 50 and then applied to the port "1" of the first optical signal rotating unit 31 via the optical signal switching unit 40 again. The preliminary optical signal applied to port "1" of the first optical signal rotating unit 31 is rotated by the optical circulator 35 and output to port "2" to "0" of the second optical signal rotating unit 32. To port 1 The preliminary optical signal is processed in the same manner as in the optical signal rotating unit 31 in the remaining optical signal rotating units 32 to 34. That is, the preliminary optical signal is sequentially rotated by the optical signal rotating units 32 to 34 and transmitted to the corresponding reflector 50 in the subscriber's home, and then reflected by the reflector 50 and returned.

However, if a failure such as an optical cable disconnection or a bad connector contact occurs in one subscriber branch operating optical line Lm, and the operating optical signal is not transmitted to the ONU 2 or the intensity of the operating optical signal falls below the threshold, the switching control unit The switching signal generator 63 of 60 detects this and activates the switching signal Ssw and outputs it to the optical signal switching unit 40.

)을 갖는 예비용 광신호를 이용하여 OLT(1)와 정상적으로 데이터 통신을 수행할 수 있게 된다.When the switching signal Ssw is activated, the optical signal switching unit 40 crosses the optical path as shown by the dotted line in FIG. 4 so that the spare optical signal is applied to the ONU 2. Therefore, the corresponding ONU 2 has a wavelength (

By using the spare optical signal having a) it is possible to perform normal data communication with the OLT (1).

After the obstacle is overcome and the operating optical signal is normally transmitted through the subscriber branch operating light line (Lm), the switching signal generator 63 detects this again and deactivates the switching signal Ssw. As a result, the optical signal switching unit 40 switches the optical path back to the original state, thereby preventing the preliminary optical signal applied through the subscriber branch reserve optical path Ls from being applied to the ONU 2, and again to the subscriber branch operation optical path ( The operational light signal applied through Lm) is applied to the ONU 2.

As described above, the automatic optical path failure recovery system of the present invention can quickly recover the failure of the optical path by using only one spare optical signal, thereby increasing resource utilization, reducing initial investment costs, and maintaining high quality and stable communication services without interruption. Can be provided continuously. In addition, the automatic optical path failure recovery system of the present invention can automatically recover the failure without the dispatch of the field personnel when the failure occurs, it is possible to shorten the failure recovery time and reduce the maintenance cost.

Claims (8)

A preliminary light generation unit generating a preliminary optical signal and outputting the preliminary optical signal in combination with the operational optical signals; A remote node for dividing the preliminary optical signal and the operational optical signal by wavelength for output; A preliminary light distribution unit for bypassing the wavelength-divided operating optical signal to a corresponding subscriber branch operating optical path, and sequentially distributing the wavelength-divided preliminary optical signal to all subscriber-split spare optical paths; An optical signal switching unit for selectively switching a transmission path of an operational optical signal applied through the subscriber branch operating optical path and a spare optical signal applied through the subscriber branch auxiliary optical beam according to a switching signal; A reflector for reflecting and outputting an optical signal provided at an output terminal of the optical signal switching unit; And And a switching control unit for measuring the intensity of the operational optical signal and selectively activating the switching signal according to the magnitude of the measured value. The method of claim 1, wherein the preliminary light generating unit A preliminary light source generating and outputting the preliminary optical signal; And And an optical coupling unit for coupling the preliminary optical signal output from the preliminary light source with the operational optical signals output from an optical line terminal (OLT: Optical Line Terminal). The method of claim 1, wherein the preliminary light distribution unit And a plurality of optical signal rotating parts which rotate the preliminary optical signal applied to one-to-one correspondence to each subscriber optical terminal in a predetermined direction and output the corresponding optical signal to the subscriber branch reserve optical beam. According to claim 3, The optical path rotating portion The optical path failure automatic recovery system characterized in that the optical circulator. The method of claim 1, wherein the optical signal switching unit And a 2x2 optical switch for selectively connecting the subscriber branch operating light path and the subscriber branch spare light path according to the switching signal to the reflector and the subscriber optical terminal. The method of claim 5, wherein the optical signal switching unit And when the switching signal is inactivated, transmitting the operating optical signal to a corresponding subscriber optical terminal and transmitting the preliminary optical signal to the reflector. The method of claim 6, wherein the optical signal switching unit And when the switching signal is activated, transmitting the preliminary optical signal to the subscriber optical terminal and transmitting the operating optical signal to the reflector. The method of claim 1, wherein the transfer control unit An optical intensity distribution unit for dividing an intensity of the operating optical signal transmitted through the subscriber branch operating optical path; An optical intensity measuring unit measuring an intensity of the branched optical signal; And And a switching signal generator for activating the switching signal when the measured value of the light intensity measuring unit is smaller than a preset threshold.

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