CN202488457U - Optical Fiber Automatic Switching Device in DWDM System - Google Patents

Abstract

The present utility model relates to a switching device for a dense wavelength division multiplexing system, especially to an optical fiber automatic switching device of a dense wavelength division multiplexing system. The device is characterized in that the device comprises a standby optical fiber, a first optical branching device, a first optical power monitoring module, an optical path automatic protection module and a first optical switch module, the first optical branching device and the first optical switch module are successively connected in series in an active optical fiber line, an optical signal output end of the first optical branching device is connected with the optical path automatic protection module through the first optical power monitoring module, and the standby optical fiber is connected with a switch end of the first optical switch module. By adopting the device, optical path switching can be realized rapidly, stability and safety of communication can be guaranteed, safety hidden troubles of node failure can be eliminated, a loop network self-healing system can be prevented from collapsing, a business channel can be prevented from being blocked, influences on users can be reduced, and data guarantee can be provided for electric power safety production.

Description

Optical Fiber Automatic Switching Device in DWDM System

technical field

The utility model relates to a switching device for a dense wavelength division multiplexing system, in particular to an optical fiber automatic switching device in a dense wavelength division multiplexing system. the

Background technique

The transmission network is the most important basic network in the communication network. The focus of the transmission network is to develop the optical fiber communication network, and the construction of the optical cable is the foundation of the optical fiber communication network. At present, in the construction of the provincial network and the regional backbone optical cable circuit, the main construction has The overhead ground wire composite optical cable (OPGW) or metal-free self-supporting optical cable (ADSS) featured in the power system forms the backbone DWDM+SDH optical fiber ring network communication network of Fujian Electric Power. the

Among them, the construction of OPGW and ADSS is limited by the construction of power lines. There is generally only one optical cable in one direction, while the ordinary optical cable going to the city is the opposite. Due to the small investment, there are generally multiple optical cables with different routes in one direction. The DWDM+SDH optical fiber ring network communication network of the provincial network is based on the ring optical cable to form a ring network structure, and the SDH system carried by it forms an optical fiber self-healing ring network. the

However, the shortcomings of the above-mentioned optical cable construction and the provincial network DWDM+SDH optical fiber ring network communication network are:

1. The DWDM+SDH optical fiber ring network communication network of the provincial network is affected by the technical characteristics of the wavelength splitting optical link itself that can only use 2-core optical cables and the long length of the optical cable line, which makes it concentrated on the weakness of resisting N-2 faults. This weak problem is mainly manifested in: A. The backup communication systems (mainly 2M channels provided by 34M PDH digital microwave and 155M regional optical network interconnection) cannot fully provide sufficient bandwidth; B. The current network cannot resist two interruptions, There is a potential safety hazard of WDM node failure. Once the WDM node fails, the important business (power production and management business) information of these sites will not be delivered to the provincial company, which will bring serious consequences.

2. Due to the development needs of the power network, these OPGWs are often interrupted in the face of power line maintenance, and sometimes need to be added or reconnected to a new substation with the power line being disconnected, which will inevitably cause a certain wavelength division link (a multiplex section, namely OTM segment (or Link, Span) is interrupted, causing the self-healing system of the SDH ring network carried by it to collapse and become a chain structure. For example, this state occurred most seriously in a certain province from November 17 to December 28, 2007. Within 40 days, OPGW and ordinary optical cables were planned to be disconnected as many as 11 times, and the cumulative time was close to 100 hours. According to the operating records of the whole year in 2007, such OPGW planned interruptions occurred 18 times in total, and the accumulated time was close to 127 hours. the

3. Due to the current period of rapid urban development, overhead optical cables often need to be changed to buried methods, and the optical cables are also temporarily cut off. At the same time, unexpected optical cable interruptions (such as being hung up by super-high vehicles, being stolen, cables explosion, etc.). the

4. In the case of the interruption of the WDM ring network optical cable, the interruption of the OPGW is planned, while the interruption of the urban optical cable is mostly uncertain. Once there are two interruptions in the ring network optical cable, there will inevitably be two interruption points far away from the province. The company's communication node lost contact with the provincial company, causing a large number of business channels to be interrupted, affecting power safety production and enterprise management. the

The reason for the above problems is that there are two directions for the urban optical cables from the dense wavelength division system to the various ground adjustments, and only ordinary optical cables in these two directions can be used. Connect 2-core pigtail. In addition, ordinary optical cables entering the city have the characteristics of multi-directional and multi-routing, but they cannot be used effectively by the WDM system at the same time. the

Utility model content

The purpose of the utility model is to provide an optical fiber automatic switching device in a dense wavelength division multiplexing system with safe information transmission, no interruption or reduced interruption time according to the deficiencies of the prior art. the

The purpose of this utility model is achieved by the following approaches:

The key point of the structure of the optical fiber automatic switching device in the dense wavelength division multiplexing system is that it includes a spare optical fiber, a first optical splitter, a first optical power monitoring module, an optical path automatic protection module and a first optical switch module. An optical splitter and the first optical switch module are serially connected in the main optical fiber line, the optical signal output end of the first optical splitter is connected to the optical path automatic protection module through the first optical power monitoring module, and the backup optical fiber is connected to To the switch end of the first optical switch module; wherein: the optical path automatic protection module includes a comparison processing unit and a reference unit connected thereto, the input end of the comparison processing unit is connected to the first optical power monitoring module, and the trigger output end is connected to the first optical power monitoring module. The switch module is connected, and the set switching optical power value is stored in the reference unit.

The first optical splitter separates a part of the optical signal from the main optical fiber line, the optical signal is sent to the first optical power monitoring module, and the optical power monitoring module measures the optical power data of the main optical fiber line through calculation and processing, And sent to the optical path automatic protection module, the comparison processing unit in the optical path automatic protection module compares the measured optical power data with the switching optical power value stored in the reference unit, if the measured optical power value is within the reference range, then Indicates that the communication of the current active optical fiber line is normal, and no optical path switching is required; if the measured optical power value deviates from the reference value range, it indicates that the communication of the current active optical fiber line is faulty. At this time, the comparison processing unit generates a trigger command and passes the trigger The terminal is sent to the first optical switch module, and the switch terminal is switched to the standby optical fiber line by the first optical switch module. the

The spare optical fiber can be various ordinary optical cables distributed in the same direction as the main optical fiber line, so as to make full use of optical cable resources. In this way, through the real-time monitoring and measurement of the optical power of the main optical fiber line, the optical power value is obtained, and based on this, it is judged whether to switch the optical path, which realizes the rapid switching of the optical path, ensures the stability and safety of communication, and eliminates the potential safety hazard of node failure , avoiding the disintegration of the self-healing system of the ring network, ensuring the smooth flow of business channels, reducing the impact on users, and providing data guarantee for power safety production. the

The utility model can be further specifically described as:

It also includes a second optical splitter and a second optical power monitoring module, the second optical splitter is connected in series in the standby optical fiber line, its main branching path is connected to the switch end of the first switch module, and the other branching path is connected to the switch end of the first switch module. The second optical power monitoring module is connected, and the data output end of the second optical power monitoring module is connected to the receiving end of the comparison processing unit in the optical path automatic protection module.

When the main optical fiber line fails and the first optical switch module switches to the backup fiber, the optical path automatic protection module will monitor the backup fiber through the second optical power monitoring module, obtain the optical power value of the backup fiber, and judge the communication of the backup fiber When the main optical fiber line is maintained and connected, the optical fiber line can be switched again according to the monitoring data. the

The optical power monitoring module includes sequentially connected PIN photodetectors, chopper-stabilized zero program-controlled amplifiers, program-controlled filters, A/D converters and microprocessors. the

The PIN refers to a silicon surface junction diode, a crystal diode constructed by sandwiching a layer of intrinsic semiconductor (or semiconductor with low concentration of impurities) between the P region and the N region. In the optical power monitoring module, part of the optical power separated by the optical fiber line through the optical splitter is detected by the PIN photodetector and converted into a photocurrent, and the current signal is converted into a voltage signal by the subsequent chopper-stabilized zero-stabilized program-controlled amplifier, which realizes I/V is converted and amplified, and then sent to the A/D converter to become a digital signal corresponding to the input optical power level after being filtered by the program-controlled filter to filter out the additional component of chopping and the interference signal, which is controlled by the microprocessor (CPU) Perform data processing. The CPU can automatically set the range state and filter state according to the injected optical power, and at the same time accept input instructions to complete the specified work. the

The PIN photodetector can be a new generation of high-speed PIN photodetector, such as the photodetector model OPD-P-3-A-85-FP. The new generation of high-speed PIN optical detectors can cover the power range from +23dBm to -50dBm, the effective detection wavelength can reach 850nm to 1700nm, and the sampling speed can reach 1ms, which can quickly determine the link status, and then quickly issue control commands to achieve fast optical The effect of link switching minimizes the impact on users and achieves the purpose of uninterrupted services. the

In the optical fiber communication system, there are mainly two types of optical path models, which are described according to the technical solution of the utility model:

The first is the 1:1 optical path model:

It includes a second optical switch module whose control end is connected to the trigger end of the optical path automatic protection module. The second optical switch module has one input optical path and two output optical paths, that is, the main output optical path and the standby output optical path.

In the DWDM+SDH optical fiber ring network communication network of the provincial network, since the two devices of the dense wavelength division system are connected through optical amplifiers, only 2-core pigtails can be connected, so they are all optical path modes of one receiving and one sending. On the receiving link, when the main optical fiber line fails, after switching to the backup fiber through the optical fiber automatic switching device, the sending link should also be switched to the backup fiber for transmission, so the second optical switch module realizes the transmission link. switching, the switching trigger signal is provided by the optical fiber automatic protection module. the

In this way, in the 1:1 optical path model, the optical fiber automatic switching device is used at the transmitting end to route the transmitting optical channel, and the protected optical signal can only be along the main optical fiber (also called the working optical fiber) or the standby optical fiber (or called To protect the optical fiber) transmission (selection). At the receiving end, the optical fiber automatic switching device is also used to selectively receive (selectively receive) the optical signals of the main optical fiber and the standby optical fiber. In order to ensure that the receiving channel and the sending channel can be consistent, when the working optical fiber fails, the sending end and the receiving The end should be switched to the main optical fiber (backup optical fiber) at the same time. That is to say, the working mode of the 1:1 optical fiber automatic switching technology is the selective transmission and selective reception mode, and the reception and transmission are switched together when either end of the reception and transmission is disconnected. the

The second is the 1+1 optical path mode:

It includes a third optical splitter, the input end of which is connected to the sending end of the optical path, and the separated optical signals are respectively connected to the main optical fiber and the standby optical fiber.

Since the sending end of the 1+1 optical path mode uses an optical splitter (Splitter) to separate the optical signal, usually a 50:50 optical splitter is used (in practical applications, due to the different routing of the main fiber and the backup fiber, you can use Optical splitters with different splitting ratios), the split optical signals are transmitted (concurrently) in the main optical fiber and the backup optical fiber respectively. The optical channel selection device is used in the optical fiber at the receiving end to select (receive) the optical signals of the main optical fiber and the standby optical fiber. When the main route fails, the receiving end automatically selects to receive from the backup fiber. That is to say, the working mode of the 1+1 optical fiber automatic switching technology is the concurrent selective reception mode (dual transmission and selective reception). When switching, 1+1 means that the sending end is disconnected and only the sending end is switched. the

The switching time of the 1+1 optical path model is faster than that of the 1:1 optical path model, but both meet <50ms (ITU-T standard); the difference is: 1. The main disadvantage of 1+1 is that the insertion loss is larger than that of 1:1. The power redundancy of the original optical link is greatly reduced. In engineering design, the redundancy of the general optical path is 3dB to 5dB, so the scope of application is narrow. And 1:1 can ensure that the optical link always works on the same optical cable (transmitting and receiving on the same cable), which is especially suitable for some special users, such as current differential protection information in the power system. 2. The 1:1 optical link automatic switching system can conveniently transmit network management information through the backup optical path, but 1+1 cannot be realized, and only an external independent channel can be used for network management communication transmission. 3. At the same time, it is difficult to ensure that the receiving and receiving optical paths of the 1+1 optical fiber automatic switching equipment are on the same optical cable route, which has a great impact on the design model of the system. Therefore, the 1:1 optical path model is the preferred technical solution. the

In summary, the utility model provides an optical fiber automatic switching device in a dense wavelength division multiplexing system. According to the optical power monitoring data provided by the optical power monitoring module as the basis for judging the switch, a spare optical fiber is provided. When an optical fiber fails, it can automatically switch to the backup optical fiber, realizing fast switching of optical paths, ensuring the stability and safety of communication, eliminating the potential safety hazard of node failure, avoiding the collapse of the self-healing system of the ring network, ensuring the smooth flow of business channels, reducing The impact on users is minimized, and data guarantee is provided for the safe production of electric power. the

Description of drawings

Figure 1 is a schematic diagram of the optical path structure of the optical fiber automatic switching device in the 1:1 dense wavelength division multiplexing system described in the present invention, R1 and T1 are respectively the main optical fiber transceiver lines, and R2 and T2 are respectively the spare optical fibers Send and receive lines. the

Figure 2 is a schematic diagram of the optical path structure of the optical fiber automatic switching device in the 1+1 dense wavelength division multiplexing system described in the present invention, R1 and T1 are respectively the main optical fiber transceiver lines, and R2 and T2 are respectively the standby optical fiber transceivers line. the

Fig. 3 is a schematic structural diagram of the working principle of the optical fiber automatic switching device in the dense wavelength division multiplexing system of the present invention, taking the 1:1 type as an example. the

Below in conjunction with embodiment the utility model is described further. the

specific embodiment

Best practice:

With reference to accompanying drawing 1 and accompanying drawing 2, the optical fiber automatic switching device in dense wavelength division multiplexing system includes main optical fiber, spare optical fiber, first optical splitter, second optical splitter, first optical power monitoring module, the second optical power monitoring module, the optical path automatic protection module and the first optical switch module. Wherein: the first optical splitter and the first optical switch module are serially connected in the main optical fiber line, and the optical signal output end of the first optical splitter is connected to the optical path automatic protection module through the first optical power monitoring module; The second optical splitter is connected in series in the standby optical fiber line, its main split optical path is connected to the switch end of the first switch module, and the other split optical path is connected to the second optical power monitoring module, the first optical power monitoring module and the second optical power monitoring module The optical power monitoring modules are respectively connected to the first optical switch module through the optical path automatic protection module.

Referring to accompanying drawing 1, in 1:1 type optical path model, also comprise the second optical switch module, its control end is connected with the trigger end of optical path automatic protection module, the input optical path of the second optical switch module is one way, the output optical path is Two paths, the main output optical path and the backup output optical path. the

Referring to accompanying drawing 2, in the 1+1 type optical path model, also includes the 3rd optical splitter, is a kind of splitter of 50:50, its input end is connected with optical path sending end, and the optical signal after splitting is respectively connected Primary fiber and backup fiber. the

In Figure 1 and Figure 2, the thick line is the optical path, and the thin line is the circuit. the

Referring to accompanying drawing 3, the optical power monitoring module includes sequentially connected PIN photodetectors, chopper-stabilized zero program-controlled amplifiers, program-controlled filters, A/D converters and microprocessors. The optical path automatic protection module includes a comparison processing unit and a reference unit connected thereto. The input end of the comparison processing unit is connected to the first optical power monitoring module, and the trigger output end is connected to the first optical switch module. Switch the optical power value. the

Each of the above modules can use a commercially available circuit module or optical path module, especially the PIN photodetector, which requires a new generation of high-speed PIN photodetector. For the working principle, refer to the content of the utility model. the

The optical fiber automatic switching device in the dense wavelength division multiplexing system described in the utility model also has the following auxiliary modules (not shown in the drawings):

1. Power failure protection module. When the optical fiber automatic switching device is powered off (referring to the partial power failure of the circuit), the system will not disconnect the communication and keep working on the original route. When the device is powered on, the circuit will not change its original route and continue to work.

2. Panel control and indication part. The user can select the mode of manual optical path switching and automatic optical path switching through the buttons on the panel. The indication part displays the working mode status, monitoring optical power indication status, alarm status, switching prompt and optical path connection. the

3. Serial port and network port control part. The user can set the switching optical power value through the serial port and the network port, and monitor the online optical power on the main and standby channels. You can also set whether the protection system works in manual switching mode or automatic switching mode through the serial port and network port, and can use real-time display to monitor the optical power status of the equipment channel in real time, and display the current working status of the main and standby channels. the

4. Optical communication module. For equipment with 1:1 automatic optical switching technology, the in-band mode can be used to transmit network management information, and the real-time monitoring of the main and standby optical cables can be realized through the spare fiber core resources. the

The analysis of the impact of the optical fiber automatic switching device on the dense wavelength division system, that is, the technical difficulties to be solved when the optical fiber automatic switching device is applied in the dense wavelength division multiplexing system also includes:

1. The addition of an optical fiber automatic switching system on the optical link has a certain impact on the original system, which is mainly reflected in the inherent insertion attenuation of the equipment, which increases the total link attenuation of the original link, thus reducing the receiving Signal redundancy, resulting in the decline of the original receiving power. In the 5-year test analysis, it is found that as long as the link attenuation is still within the design model, the original design model can be directly used. Once the light receiving power at the receiving end is too low, EDFA should be used to amplify the signal to meet the power requirement.

2. Since the WDM system uses single-mode optical fiber transmission as the transmission medium, the dispersion of single-mode optical fiber is mainly material dispersion, waveguide dispersion and refraction profile dispersion. In the design of dense wavelength division system model, material dispersion is the most important factor. When the optical link of 10Gbps and above exceeds 60 kilometers, the dispersion compensation module is used. For the communication system with large capacity, consider using the dispersion compensation module with slope function modules. After the automatic fiber switching equipment is added to the wavelength division link, because of its transparent transmission characteristics, it does not increase the material dispersion, which shows that it has the conditions to apply the automatic fiber switching technology. For waveguide dispersion, since there is actually only one mode (fundamental mode LP01) in engineering, it is only necessary to consider the phenomenon of pulse broadening caused by the difference in group velocity caused by the change of propagation constant. After the automatic fiber switching equipment is added to the WDM link, due to its transparent transmission characteristics, the propagation constant is not affected, so the waveguide dispersion is the same as the original model, making the WDM link eligible for the application of fiber automatic switching technology. the

The undescribed part of the utility model is the same as the prior art. the

Claims (5)

1. The optical fiber automatic switching device in the dense wavelength division multiplexing system is characterized in that it includes a spare optical fiber, the first optical splitter, the first optical power monitoring module, the optical path automatic protection module and the first optical switch module, The first optical splitter and the first optical switch module are sequentially connected in the main optical fiber line, the optical signal output end of the first optical splitter is connected to the optical path automatic protection module through the first optical power monitoring module, and the backup optical fiber Connected to the switch end of the first optical switch module; wherein: the optical path automatic protection module includes a comparison processing unit and a reference unit connected thereto, the input end of the comparison processing unit is connected to the first optical power monitoring module, and the trigger output end is connected to the first optical power monitoring module. The optical switch module is connected, and the set switching optical power value is stored in the reference unit. 2. The optical fiber automatic switching device in the dense wavelength division multiplexing system according to claim 1, further comprising a second optical splitter and a second optical power monitoring module, the second optical splitter string Connected to the standby optical fiber line, the main sub-optical path is connected to the switch end of the first switch module, the other sub-optical path is connected to the second optical power monitoring module, and the data output end of the second optical power monitoring module is connected to the optical path automatic protection module. The receiving end of the comparison processing unit is connected. 3. according to claim 1 and the described optical fiber automatic switching device in the dense wavelength division multiplexing system of claim 2, it is characterized in that, described optical power monitoring module comprises the PIN photodetector that connects in sequence, chopper stabilizing zero Programmable amplifier, programmable filter, A/D converter and microprocessor. 4. the optical fiber automatic switching device in the dense wavelength division multiplexing system according to claim 1, is characterized in that, comprises the second optical switch module, and its control end is connected with the trigger end of optical path automatic protection module, and the second optical switch module The switch module has one input optical path and two output optical paths, that is, the main output optical path and the standby output optical path. 5. the optical fiber automatic switching device in the dense wavelength division multiplexing system according to claim 1, is characterized in that, comprises the 3rd optical splitter, its input end connects optical path sending end, the optical signal after separation connects respectively Primary fiber and backup fiber.

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