KR20050022034A - A protection structure for an optical module on passive optical network - Google Patents

Abstract

PURPOSE: A structure for protecting an optical module of a PON(Passive Optical Network) is provided to prevent suspension of a system when an optical module is failed and lengthen an available time of the system. CONSTITUTION: An optical module(201) performs communication with an adjacent node connected with an optical line. An optical signal distribution module(207) distributes an optical communication signal provided from the optical module(201) to a plurality of receiving side optical modules. A backup optical module(203) and the optical module(201) are connected in parallel with an optical signal switching module(205) and the backup optical module(203) substitutes a function of the optical module(201) when the optical module(201) is failed. The optical signal switching module(205) receives an optical signal from the optical module(201) or from the backup optical module(205) or transmits an optical signal to the optical module(201) or to the backup optical module(205).

Description

A PROTECTION STRUCTURE FOR AN OPTICAL MODULE ON PASSIVE OPTICAL NETWORK}

The present invention relates to a structure of a passive optical network, and more particularly, by adding a backup optical module and an optical signal switching module on a passive optical network so that the system does not stop even when an error occurs in the optical module. An optical module protection structure of a passive optical network.

Optical network technology is a technology for constructing a communication network system that can provide high-speed information and communication service to each subscriber more economically. Until now, it provides a direct optical path to a subscriber terminal or a combination of existing copper wire and optical path. By providing a communication network system in the form of a high speed service has been provided.

However, according to the method of directly providing the optical fiber to the subscriber terminal, the high price of the optical cable and the optical device brings economic difficulties in the current state.

Therefore, in order to implement an optical network more economically, a passive optical network (or passive optical network (PON)) system, in which several subscribers share one optical fiber as shown in FIG. 1, is widely introduced in recent years. As a signal transmission method using a passive optical network, a time division multiplex (TDM), a wavelength division multiplex (WDM), or a subcarrier multiplex (SCM) is used. Various techniques are used.

However, the passive optical network as described above has the advantage of economical in network configuration, while the serious problem that the service of the entire network should be stopped in case of an error in the central station optical module or an error in the optical path. There are disadvantages that can result.

In other words, the core of the network configuration according to the prior art is to form a network of optical signal through a passive optical splitter or, if necessary, an optical amplifier, a one-to-many corresponding structure. Since such a configuration has no backup of the optical module, the central station ( If an error occurs in the optical module in the center), the service of the entire network may be stopped.

Of course, as a method to solve the above problems, a system that can maintain the service by changing the line when an error occurs in the optical module by installing a double line, but this method is a service cost due to the huge increase in facility costs Increasingly, it is not a desirable alternative from the user's point of view.

The present invention was created in order to solve the above problems, by adding a backup optical module and an optical signal switching module on the passive optical network, so that the system does not stop even when an error occurs in the optical module. It is an object to provide an optical module protection structure of an optical network.

An optical module protection structure of a passive optical network according to the present invention for achieving the above object, in the passive optical network consisting of an optical module and an optical signal distribution module, the passive optical network is a backup optical module and An optical signal switching module is further included, wherein the backup optical module is connected in parallel with the optical module to act as an optical module when a failure occurs in the optical module, and the optical signal switching module divides the optical module and the optical signal. Located between the modules, and receives the optical signal of any one of the optical module or the backup optical module and transmits to the optical signal distribution module.

In addition, in the optical module protection structure of the passive optical network according to the present invention for achieving the above object, the optical signal switching module selectively converts the optical signal provided from the optical module or the backup optical module to the optical signal distribution module. An actuator for flow control of said plurality of mirrors, including a plurality of mirrors for reflecting; An optical coupler for distributing a part of the optical signal provided from the optical module; An optical detector for determining whether an optical signal level of the optical signal detected by the optical coupler is within a reference value, and outputting the determination result as an electrical signal; And a driver for operating the actuator according to the determination result of the photo detector.

In the optical signal switching module according to the present invention, the optical module and the backup optical module use different wavelengths, and the optical signal switching module outputs the optical signal output from the optical module when the optical module is in a normal state. A wavelength that is connected to a signal distribution module, and when an error of the optical module occurs, an output optical signal of the optical module is turned off, an output optical signal of the backup optical module is turned on, and an output optical signal of the backup optical module is provided to the optical signal distribution module. The optical transmission system has a wavelength division multiplexing (WDM) optical switching structure.

In addition, the optical signal switching module according to the present invention, the first optical coupler for distributing a part of the optical signal provided from the optical module, the first optical detector for converting the optical signal distributed from the first optical coupler into an electrical signal A second optical coupler for distributing a portion of the optical signal provided from the backup optical module, a second photodetector, a first photodetector and a second photodetector for converting the optical signal distributed from the second optical coupler into an electrical signal A signal processor for detecting a level of a signal provided from the signal and determining whether the detected signal is a reference value and generating a corresponding switching signal and an error alarm signal, and an optical signal of an optical module or a backup optical module according to the switching signal of the signal processor. Characterized in that consists of a wavelength multiplexer for switching.

In addition, the optical signal switching module according to the invention is characterized in that the optical 2xN coupler integrally formed with the optical signal distribution module.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

2 is an optical protection structure of a passive optical network showing a technical spirit of the present invention. As shown, the optical connection structure according to the present invention further includes a backup optical module 203 and an optical signal switching module 205 in addition to the optical module 201 and the optical signal distribution module 207 included in the prior art. . Here, the optical module 201 is connected on the optical path to perform a communication function with adjacent nodes, the optical signal distribution module 207 is a plurality of optical communication signals provided from the optical module 201 It serves to distribute to the receiving optical module 208.

In addition, the backup optical module 203 is connected in parallel to the optical module 201 and the optical signal switching module 205 serves to replace the function of the optical module 201 when a failure of the optical module 201 occurs. The optical signal switching module 205 is responsible for receiving or transmitting an optical signal to any one of the optical module 201 or the backup optical module 203.

FIG. 3 is an embodiment in which the optical signal switching module 205 of FIG. 2 is configured as an optical switch. As shown, the first optical fiber 301 for transmitting the optical signal provided from the optical module 201 to the optical signal switching module 205, and the backup light at the input and output terminals of the optical signal switching module 205, A second optical fiber 303 for transmitting the optical signal provided from the module 203 to the optical signal switching module 205 and an optical signal transferred from the optical signal switching module 205 to the optical signal distribution module 207. Is connected to a third optical fiber 309 for transmission.

The optical signal switching module 205 includes an optical coupler 311, a photodetector 305, and a driver 307, including a first lens 315, a second lens 313, a first mirror 319, and a first lens. It consists of two mirrors 321. When the optical module 201 operates normally, the driver 307 transmits an optical signal provided from the first optical fiber 301 to the third optical fiber 309 through the optical coupler 311 and the first lens 315. The actuator 317 is operated upward so as to be able to do so. That is, when the system is in a normal state, the actuator 317 is operated upward in the drawing under the control of the driver 307, whereby the optical signal provided through the first lens 315 is transferred to the third optical fiber 309. Is sent straight to. At this time, the optical signal of the backup optical module 203 provided through the second lens 313 is caused by the third optical fiber 309 due to the upward movement of the second mirror 321 in association with the first mirror 319. Does not provide an optical signal.

The optical coupler 311 is an element for providing an optical signal provided from the first optical fiber 301 to the first lens 315 and the photodetector 305, and the photodetector 305 is an optical coupler 311. The level of the optical signal provided from the first optical fiber 301 is detected through. The photodetector 305 includes a photodiode (not shown) for converting the optical signal reflected from the optical coupler 311 into an electrical signal, and an amplifier for amplifying the electrical signal detected through the photodiode with a predetermined gain. (Not shown) and comparator (not shown) for determining the level of the amplified signal. The comparator determines that the optical module 201 is in an error state when the input electrical signal deviates from the reference value, and provides a corresponding signal to the driver 307.

That is, when the optical signal is not transmitted due to an error of the optical module 201, the optical module 201 rapidly decreases the level of the light source as the optical module 201 provides a light source having no signal, and the optical detector 305 ) Detects it through the amplifier and the comparator. Accordingly, the photo detector 305 determines the error state of the optical module 201 based on the optical signal provided from the optical module 201, and provides the determined result signal to the driver 307.

The driver 307 determines whether to operate the actuator 317 in response to a result signal provided from the photo detector 305. This is when the optical module 201 is in a normal state, the photo detector 305 notifies the driver 307, the driver 307 maintains the operating state of the actuator 317 to the initial state. That is, the actuator 317 is moved so that the first mirror 319 is deviated from the trajectory of the optical signal so that the optical signal provided from the optical module 201 is provided to the third optical fiber 309 via the first lens 315. To control.

On the other hand, when it is determined by the photodetector 305 that the optical signal below the reference level is determined as abnormal, the optical module 201 has occurred. Therefore, the driver 307 drives the actuator 317, The optical signal provided from the second lens 313 is controlled to be supplied to the third optical fiber 309. This is because the optical signal provided from the backup optical module 203 is provided to the second lens 313 through the second optical fiber 303, and then the second mirror 321 and the first mirror 319 of the actuator 317 are closed. It is supplied to the third optical fiber 309 via. As a result, even when an error occurs in the optical module 201, the optical signal is smoothly transmitted through the backup optical module 203.

In addition, the optical network protection structure according to the present invention receives the optical signal through the third optical fiber 309 in the initial state of the actuator 317 through the first lens 315 and the optical coupler 311 through the first It can transmit to the optical fiber 301 can also be used for two-way optical communication. At this time, by receiving an abnormal signal generated at the receiver abnormality of the optical module to drive the actuator to lead the receiving path to the backup optical module can have a protection function in the bidirectional communication.

4 is a configuration diagram showing a second embodiment of the optical signal switching module 205 according to the present invention. In the present embodiment, an optical signal switching module using a wavelength division multiplexing (WDM) is shown. The multiplexing is performed by different wavelengths by using different wavelengths of the optical module 201 and the backup optical module 203. When the optical module 201 is in a normal state, the optical module 201 is connected to the optical signal distribution module 207. When an error of 201 occurs, the optical output of the optical module 201 is turned off, and the optical output of the backup optical module 203 is turned on to provide optical signals of different wavelengths to the optical signal distribution module 207.

A first optical coupler 401 for distributing a part of the optical signal provided from the optical module 201, and a first optical detector for converting the optical signal distributed from the first optical coupler 401 into an electrical signal ( 405, a second optical coupler 403 for distributing a part of the optical signal provided from the backup optical module 203, and a second optical coupler 403 for converting the optical signal distributed from the second optical coupler 403 into an electrical signal. Detects the level of the signal provided from the second photodetector 407, the first photodetector 405, and the second photodetector 407, determines whether the detected signal is a reference value, and transfers the corresponding switching signal and the error alarm signal. And a wavelength multiplexer 411 for switching the optical signal of the optical module 201 or the backup optical module 203 according to the switching signal of the signal processor 409. .

Therefore, the optical signals provided from the optical module 201 and the backup optical module 203 having different wavelengths are respectively distributed through the first optical coupler 401 and the second optical coupler 403. And are supplied to the first photodetector 405 and the second photodetector 407. The first photodetector 405 and the second photodetector 407 each generate an electrical signal corresponding to the level of the divided optical signal and transmit it to the signal processor 409.

The signal processor 409 detects a signal provided from the first photodetector 405 and, when determining that the signal level is equal to or less than a reference value, disables the optical module 201 and simultaneously turns off the backup optical module 203. Enable to allow the optical signal provided from the backup optical module 203 to be transmitted to the optical distribution module 207 via the wavelength multiplexer 411 to be switched without additional loss.

In addition, when it is determined by the signal processor 409 that the level of the signals provided by the first photodetector 405 and the second photodetector 407 is below a reference value, that is, the optical module 201 and the backup If all of the optical modules 203 are in an abnormal state, a predetermined error alarm is operated.

5 is a configuration diagram showing an optical signal switching module using an optical coupler as a third embodiment of the optical signal switching module 205 according to the present invention. The optical coupler uses a laser diode, and the optical signal provided through the light receiving unit is a structure in which the optical signal is generated in the light emitting unit. There is no optical loss, and the optical loss between the optical module 201 and the optical switching module 205 is provided. It includes a function to compensate. In addition, the wavelength used in the optical module 201 and the backup optical module 203 does not have to be different.

As shown first, the optical signal switching module 205 includes an optical coupler 505, a photodetector 511, a controller 513, a first light receiver 507, a second light receiver 501, and a first light emitter ( 509 and a second light emitting portion 503, denoted by '515'.

The optical coupler 505 receives a portion of the optical signal incident from the optical module 201 and supplies the optical signal to the photodetector 511. The photodetector 511 measures the level of the optical signal supplied from the optical coupler 505 and generates a result signal according to whether or not the reference value is greater than or equal to the reference value. The controller 513 selectively controls the first light emitting part 509 or the second light emitting part 503 based on the result signal provided from the photodetector 511.

The first light receiver 507 receives a signal of the optical module 201 incident through the optical coupler 505, and the second light receiver 501 receives an optical signal provided from the backup optical module 203. Each of the received optical signals is provided to the first light emitting unit 509 and the second light emitting unit 503 which act as respective couplers to perform amplification output of the optical signal. Any one of the output optical signals of the first light emitting unit 509 and the second light emitting unit 503 is supplied to the optical signal distribution module 207 through the connector 515 or the coupler.

In the embodiment of the present invention according to the above configuration, the optical signal provided from the optical module 201 is a part of the optical signal is branched through the optical coupler 505, the first light receiving unit 507 consisting of an optical coupler And the first light emitting unit 509. At this time, the optical signal provided through the first light emitting unit 509 is supplied to the optical signal distribution module 207 to maintain the normal flow of the optical signal. This is because the controller 513 enables the first light emitter 509 as the level of the optical signal detected through the optical coupler 505 and the photodetector 511 is in the normal range.

On the other hand, when the optical signal of the optical module 201 detected through the optical coupler 505 and the photodetector 511 does not exist within the reference value range, that is, the optical level is abruptly lowered due to an abnormal occurrence of the optical module 201. When detecting, the photodetector 511 notifies the controller 513, and the controller 513 disables the first light emitter 509 and then enables the second light emitter 503. Therefore, the optical signal provided from the backup optical module 203 is received through the second light receiving unit 501 and then supplied to the second light emitting unit 503. The second light emitting unit 503 amplifies the optical signal to a predetermined level and supplies it to the optical signal distribution module 207 through the connector 515. Therefore, when an abnormality occurs in the optical module 201, the optical module 201 switches to the optical signal supplied from the backup optical module 203.

Meanwhile, FIG. 6 shows a structure in which the optical signal switching module 205 and the optical signal distribution module 207 are integrated as another embodiment of the present invention.

That is, in FIG. 6, when the optical signal switching module 205 receives one of the signals of the two optical modules 201 and 203 and transmits it to the optical signal distribution module 207, the optical signal distribution module 207 again returns it. Although there is a complicated structure of distributing to a plurality of receiving side optical modules, in this embodiment, the input / output signal of the optical module 201 is directly received through the optical 2 × N coupler 600 in the normal state. When the error occurs in the optical module 201, the output of the backup optical module 203 is turned on and connected to the receiving optical module (not shown) via the optical 2 × N coupler 600. It has a structure.

In particular, when the optical signal switching module 205 using the optical coupler of FIG. 5 is integrated with the optical signal distribution module 207, each of the N light emitting units for the first light receiving unit 507 and the second light receiving unit 501 is provided. By placing it, the optical 2xN coupler 600 can be comprised easily. That is, as shown in FIG. 7, the optical switching module 205 is integrally formed with the optical distribution module 207, and includes the 2 × N coupler 701 and the optical module 201 and the backup optical module 203. And an optocoupler, a photodetector, and a signal processor. Since the operation of the optocoupler, photodetector, and signal processor has the same operation as described above, redundant description is omitted. Therefore, the signal of the optical module 201 or the backup optical module 203 input to the 2 × N coupler 701 is distributed to a plurality of lower optical modules.

As described above, the configuration in which the optical signal switching module and the optical signal distribution module are integrated is not applicable to the conventional optical fiber double ring structure, and is applicable only to the passive optical network for the subscriber network. In addition to simplifying the system, passive switching devices can be used to combine the optical transfer function and the optical distribution function without additional failure points without additional optical loss or cost.

The optical module protection structure of the passive optical network according to the present invention described above is just one embodiment, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, the gist of the present invention. Without departing from the technical spirit of the present invention to the extent that any person of ordinary skill in the art to which the present invention pertains various modifications can be made.

As described above, the optical module protection structure of the passive optical network according to the present invention includes a backup optical module for backing up the optical signal provided from the optical module and an optical signal for switching the output optical signal of the optical module and the backup optical module. With a switching module, it is possible to replace the backup optical module when an abnormal signal of the optical module occurs, so that the problem that the service of the entire system is interrupted even in the event of a failure of the optical module can be eliminated in advance, as well as the available time of the system. There is an excellent effect to increase.

In addition, by implementing the optical signal switching module with optical switch, optical splitting function using wavelength division multiplexing (WDM) and optical coupler, it can be utilized in bidirectional optical path as well as unidirectional, reducing the development and maintenance cost of system. Get

In addition, by combining the optical signal switching module and the optical signal distribution module integrally, it is possible to implement the optical switching function and the optical distribution function as one without using additional passive points without additional optical loss or cost burden. have.

1 is a block diagram of a passive optical network according to the prior art.

2 is a configuration diagram illustrating the technical idea of the present invention.

3 is a configuration diagram according to a first embodiment in which the optical signal switching module of FIG. 2 is implemented as an optical switch.

FIG. 4 is a diagram illustrating a second embodiment in which the optical signal switching module of FIG. 2 is implemented by wavelength division multiplexing (WDM).

FIG. 5 is a diagram illustrating a third embodiment in which the optical signal switching module of FIG. 2 is implemented as an optical coupler.

6 is a configuration diagram according to another embodiment of the optical signal switching module of FIG. 2.

FIG. 7 is a block diagram illustrating an integrated optical signal switching module embodying FIG. 6.

<Explanation of symbols for main drawings>

101: optical module 103: backup optical module

105: optical signal switching module 107: optical signal distribution module

205: photodetector 207: driver

211: optocoupler 217: actuator

301: branch coupler 303: wavelength selective filter

305: first photodetector 307: second photodetector

309 signal processor 413 controller

Claims (5)

In a passive optical network consisting of an optical module and an optical signal distribution module, The passive optical network further includes a backup optical module and an optical signal switching module, The backup optical module is connected in parallel with the optical module to act as an optical module when a failure occurs in the optical module, The optical signal switching module is located between the optical module and the optical signal distribution module and receives the optical signal of any one of the optical module or the backup optical module and transmits to the optical signal distribution module. Optical module protection structure. The optical signal switching module of claim 1, wherein the optical signal switching module includes a plurality of mirrors for selectively reflecting an optical signal provided from the optical module or the backup optical module to the optical signal distribution module. An actuator for controlling; An optical coupler for distributing a part of the optical signal provided from the optical module; An optical detector for determining whether an optical signal level of the optical signal detected by the optical coupler is within a reference value, and outputting the determination result as an electrical signal; And a driver for operating the actuator according to the determination result of the optical detector. The optical module of claim 1, wherein the optical module and the backup optical module use different wavelengths, and the optical signal switching module outputs an optical signal of the optical module to be turned off when an error of the optical module occurs. And a wavelength division multiplexing (WDM) optical transmission system in which a call is turned on and an output optical signal of the backup optical module is provided to the optical signal distribution module. The optical signal switching module of claim 1, further comprising: a first optical coupler for providing an optical signal provided from the optical module to the optical signal distribution module; A second optical coupler for providing an optical signal provided from the backup optical module to the optical signal distribution module; An optical coupler for branching a part of the optical signal incident from the optical module; An optical detector for determining an optical signal level of the optical signal detected by the optical coupler and generating a control signal corresponding to the determination result; And a controller for enabling the first optocoupler or the second optocoupler based on the control signal of the photodetector. The optical module protection structure as claimed in any one of claims 1 to 4, wherein the optical signal switching module is an optical 2xN coupler integrally formed with the optical signal distribution module.