CN104796191B - A kind of transmitting device - Google Patents

Abstract

The present invention provides a transmission device, including: a line unit for generating signal light for carrying service signals; wherein, the transmission device further includes a monitoring light generating unit, a coupling unit and a signal processing unit, the monitoring light generating unit, Used to generate monitoring light for detecting the optical transmission medium; the coupling unit is used to couple the signal light and the monitoring light and send them to the optical transmission medium, and send the reflected monitoring light received from the optical transmission medium to the signal processing unit; The signal processing unit is configured to perform signal processing and analysis on the monitoring light returned by the coupling unit, and obtain the breakpoint position of the optical transmission medium. The above-mentioned transmission device works by coupling the signal light and the monitoring light on the same optical transmission medium, the detection of the optical transmission medium will not affect the existing services of the transmission network, and can realize the breakpoint of the optical transmission medium of the transmission network Or the fault point with large loss can be accurately and quickly located online in real time.

Description

a transmission device

technical field

The present invention relates to the technical field of communications, in particular to a transmission device.

Background technique

As a transmission tool, optical cable has penetrated into all areas of people's work and life, and has become the cornerstone of today's information superhighway. When the optical cable is damaged, communication will be interrupted, such as computer users cannot access the Internet, and various information cannot be transmitted. The damage to the optical cable not only brings huge economic losses to the telecommunications sector, but also brings a lot of inconvenience to the masses due to poor communication.

However, the existing transmission equipment and system network management cannot automatically monitor the optical cable alarm, and can only manually judge whether there is an optical cable interruption, and then carry out the fault point test with an OTDR instrument on site, and manually calculate the breakpoint position according to the test results, so as to perform repair work.

In the prior art, the fault and location method of the power optical cable network can be used to give early warning information to the potential hidden trouble of the optical cable; but this method needs to start the optical time domain reflectometer OTDR to detect the specified optical cable link when the optical cable is in normal state. Carry out the test, obtain the test data of the optical cable, and then draw the OTDR curve of the optical time domain reflectometer, and finally analyze and give the potential early warning information of the optical cable network. That is to say, this method must obtain accurate optical cable data information in advance, which reflects that this method cannot achieve real-time online monitoring of optical cables. In addition, if no accurate data is obtained beforehand, this method cannot give accurate information.

On the other hand, based on the relationship between existing equipment alarms and pipelines in the prior art, probabilistic calculations are used to analyze and locate optical cable faults, and end-to-end optical cable faults can be judged by this method; however, this method and its system are based on For the corresponding relationship between equipment and pipelines, using the optical cable fault analysis rules based on the algorithm of probability theory can only analyze and locate the faults of optical cable sections, such as 10KM or 5KM long optical cable sections. This undoubtedly shows that the positioning accuracy is insufficient, and it also causes the physical location of the cable fault that the maintenance personnel cannot quickly find.

Further, in the prior art, it is possible to determine whether to enable the OTDR module to test the optical cable by judging the power value of received light. Compared with the traditional hand-held OTDR instrument to test the fault point of the optical cable, this method realizes the detection from the manual on-site detection to the automatic start of the OTDR; For the test of optical cables, it is impossible to monitor the optical cables online 24 hours a day, and it is necessary to switch the optical switch to monitor the fiber core when driving the optical time domain reflectometer, which will affect the business of the normal fiber core. When an optical cable with a large number of cores is completely broken, such as a 48-core or 96-core optical cable, it is necessary to switch one by one to detect each optical transmission medium, the complexity will increase, and the detection time will also increase with the number of cores. Large and increasing, it is impossible to achieve real-time detection.

Contents of the invention

The purpose of the present invention is to provide a transmission device, which can accurately and quickly locate the fault point of the optical transmission medium online in real time without affecting the existing services of the transmission network, facilitate timely and accurate maintenance, and reduce the damage caused by the long-term damage of the optical transmission medium. economic loss to come.

In order to achieve the above object, an embodiment of the present invention provides a transmission device, including: a line unit for generating signal light for carrying service signals; wherein, the transmission device also includes a monitoring light generation unit, a coupling unit and a signal processing unit unit,

The monitoring light generating unit is used to generate monitoring light for detecting the optical transmission medium;

The coupling unit is configured to couple the signal light and the monitoring light and send them to an optical transmission medium, and send the reflected monitoring light received from the optical transmission medium to the signal processing unit;

The signal processing unit is configured to perform signal processing and analysis on the monitoring light returned by the coupling unit, and obtain the breakpoint position of the optical transmission medium.

Wherein, the coupling unit includes a coupler and a directional coupler for coupling the signal light and monitoring light and sending them to the optical transmission medium, and the directional coupler has three ports, wherein the monitoring light generation unit and The first port of the directional coupler is connected, the coupler is connected to the second port of the directional coupler, the signal processing unit is connected to the third port of the coupler, and from the first port The input optical signal is output from the second port, and the optical signal input from the second port is output from the third port.

Wherein, the transmission device also includes:

The branch unit is used for uplink transmission or downlink transmission of the service signal carried by the signal light.

The main control cross-connect unit is configured to dispatch the service signal obtained through the branch unit to the line unit, and the main control cross-connect unit is respectively connected to the branch unit and the line unit.

Wherein, the line unit includes:

A signal optical module connected to the main control cross-connect unit, configured to receive a service signal scheduled by the main control cross-connect unit, and generate signal light carrying the service signal;

The isolator connected with the signal light module is used to block the reflected signal light so that the signal light can be transmitted in one direction.

Further, the monitor light generating unit is a fiber pulse laser.

Wherein, the signal processing unit includes:

a photodetector, connected to the third port of the directional coupler, for receiving the monitoring light reflected from the optical transmission medium, and performing photoelectric conversion on the reflected monitoring light to obtain an electrical signal;

an amplifier connected to the photodetector, used to amplify the electrical signal obtained by the photodetector;

An analog-to-digital converter connected to the amplifier, configured to perform analog-to-digital conversion on the electrical signal amplified by the amplifier to obtain a digital signal;

A signal processor connected to the analog-to-digital converter is used to perform signal processing and analysis on the digital signal to obtain the breakpoint position of the optical transmission medium.

Further, the photodetector is a photodiode PIN or an avalanche photodiode APD.

Further, the signal processor performing signal processing and analysis on the analog signal specifically includes:

performing time-axis distribution processing on the digital signal;

Analyzing reflective events and non-reflective events according to the distribution of the time axis of the digital signal, and comparing them with reference data;

Determine the operating state of the optical transmission medium according to the comparison result, and calculate the breakpoint distance of the optical transmission medium if there is a breakpoint in the optical transmission medium.

Further, the branch unit is a service up and down board.

Further, the main control cross-connect unit is a main control cross-connect function board.

Wherein, the signal processing unit is also connected to a monitoring and displaying unit through the main cross-connection unit, and the monitoring and displaying unit is configured to send an alarm message according to the breakpoint position of the optical transmission medium.

Wherein, the monitor and display unit is also connected to a pipeline resource system for configuring and changing the information of the optical transmission medium.

The technical solution of the present invention has at least the following beneficial effects:

In the aluminum etching method of the embodiment of the present invention, by coupling the signal light and the monitoring light to work on the same optical transmission medium, the detection of the optical transmission medium will not affect the existing services of the transmission network, and the transmission network can be realized. The breakpoint of the optical transmission medium of the network or the fault point with large loss can be accurately and quickly located online in real time, which is convenient for timely maintenance and reduces the economic loss caused by the long-term damage of the optical transmission medium.

Description of drawings

Fig. 1 shows the basic structural diagram of the transmission device of the embodiment of the present invention;

FIG. 2 shows a schematic diagram of the overall structure of a transmission device according to an embodiment of the present invention;

FIG. 3 shows a schematic diagram of the composition of a signal processing unit in a transmission device according to an embodiment of the present invention;

Fig. 4 shows a schematic diagram of a transmission device for real-time on-line detection of optical cable breakpoints in the present invention.

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.

Aiming at the problems in the prior art that the state of the optical transmission medium cannot be detected in real time and the obtained position is inaccurate, the present invention provides a transmission device, which works by coupling the signal light and the monitoring light on the same optical transmission medium, so as to control the optical transmission The detection of the medium will not affect the existing services of the transmission network, and it can realize the real-time online accurate and fast positioning of the breakpoint or the fault point with large loss of the optical transmission medium of the transmission network, which is convenient for timely maintenance and reduces the time caused by the optical transmission medium. Economic loss caused by damage.

As shown in Figure 1, an embodiment of the present invention provides a transmission device, including: a line unit 1, used to generate signal light for carrying service signals; wherein, the transmission device also includes a monitoring light generation unit 2, a coupling unit 3 and signal processing unit 4,

A monitoring light generating unit 2, configured to generate monitoring light for detecting an optical transmission medium;

The coupling unit 3 is configured to couple the signal light and the monitoring light to the optical transmission medium, and send the reflected monitoring light received from the optical transmission medium to the signal processing unit 4;

The signal processing unit 4 is configured to perform signal processing and analysis on the monitoring light returned by the coupling unit, and obtain the breakpoint position of the optical transmission medium.

In the above-mentioned embodiments of the present invention, the transmission medium mainly refers to the wired transmission medium, and the wired transmission medium refers to the physical connection part realized between two communication devices, which can transmit signals from one party to the other. The wired transmission medium mainly includes two Twisted wires, coaxial cables, optical fibers, and optical cables, etc., wherein twisted pairs and coaxial cables transmit electrical signals, optical fibers and optical cables transmit optical signals, and the optical transmission medium in specific embodiments of the present invention refers to optical fibers or fiber optic cable. Optical fiber is a thin and soft medium that transmits light beams. Optical fiber is usually made of quartz glass. It is a double-layer concentric cylinder with a small cross-sectional area, also called fiber core. It is fragile and easy to crack; optical fiber cable It consists of a bundle of fibers, referred to as an optical cable. The optical fiber is the core part of the optical cable, and the optical fiber constitutes the optical cable after being protected by some components and its subsidiary protective layer.

In the embodiment of the present invention, the signal light and the monitoring light are used to work on the same optical fiber, the line unit 1 generates the signal light for carrying the service signal, and the monitoring light for detecting the optical fiber and the optical cable is generated by the monitoring light generating unit 2; then A coupling unit 3 is used to couple the signal light carrying the service signal and the monitoring light into the same optical fiber, so that the optical fiber and optical cable can be detected without interrupting the transmission network service. Based on the Fresnel reflection and Rayleigh scattering effects of light, the reflected monitoring light will carry reflective event information (such as the break point of the optical fiber) and non-reflective event information (such as the bending of the optical fiber). The signal processing unit 4 performs signal processing and analysis on the reflected monitoring light, so as to obtain the breakpoint position of the optical fiber or optical cable. This solution can monitor all the fiber cores in use in the optical cable in real time. It does not need to detect the switchability of the optical fiber cores one by one. The rapidity and accuracy; and the continuous detection of optical fiber and optical cable can be carried out 24 hours without switching the switching on to monitor the fiber core, which reflects the real-time detection of optical fiber and optical cable.

In addition, using the signal light and the detection light at the same time can make the two beams of light work independently. In the case of using the detection light, the idle fiber core can be monitored regularly online, and the end of the jumper fiber in the fiber distribution frame of the computer room can be monitored. , The signal light can be turned on only when there is a real business use, and can not be turned on when there is no business, which improves the working efficiency of the signal light. And the wavelength of the signal light is generally 1310nm or 1550nm, and the wavelength of the monitoring light can be selected to be different from the wavelength of the corresponding signal light, such as 1490nm or 1510nm.

At the same time, since the optical fiber includes signal light and detection light, the optical signal reaching the line unit of the peer site equipment also includes signal light and detection light; but when reaching the peer site equipment, since the detection light and signal light are lights of different wavelengths , all line units will not receive the detection light, that is, the line unit only demodulates and receives the signal light, and the detection light will form an end reflection, most of the light will be reflected back, and part of the detection light will be lost here .

In the above embodiments of the present invention, Rayleigh scattering is an inherent characteristic of the fiber material. When a narrow light pulse is injected into the fiber and propagates forward along the fiber, Rayleigh scattering will occur wherever it goes. The Rayleigh scattered light scatters in all directions, and part of the direction is opposite to the incident direction, and returns to the incident end along the optical fiber. This part of the scattered light is called backscattered light. It should be noted that the points capable of generating Rayleigh backscattering are spread throughout the entire fiber optic and are continuous.

Fresnel reflection is a discrete reflection, which is generated by individual points of the optical fiber. The points that can generate reflection generally include optical fiber connectors (gap between glass and air), smooth sections that block optical fibers, and the end of optical fibers. When the laser is continuously injected into the optical fiber, the optical fiber itself will continuously produce reverse Rayleigh scattering. By measuring and analyzing the power of these backscattered light, the attenuation curve distributed along the length of the optical fiber can be obtained. Using this technique, the locations of junctions, coupling points, and breaks in a fiber can be easily measured, as well as if a section of the fiber is bent too much or is crushed by a heavy foreign object. Backscattered light can be divided into two types: one is due to the reflection of the cross section of the fiber and the connection between the fiber and the fiber; the other is Rayleigh scattered light. In fact, when light propagates in the optical fiber, in addition to the loss caused by scattering, the optical fiber medium also absorbs the propagating light, but according to the current production capacity, impurities can be controlled to a very low level. Compared with In terms of scattered light, it will be much smaller. When the power is I ₀ and the incident light with frequency v ₀ enters the optical fiber, the Rayleigh scattered light at the optical fiber L detected by the photodetector is:

In the formula, K _R is the coefficient related to the Rayleigh scattering interface of the fiber, B is the coefficient of backscattering, and α ₀ is the transmission loss of the incident light in the fiber.

In the above-mentioned embodiments of the present invention, the signal processing unit 4 performs signal processing and analysis on the Rayleigh scattering and Fresnel reflection monitoring light of the power of each point of the laser light carrying the optical fiber and the optical cable, that is, the reflection event of the optical fiber and the optical cable Analysis with non-reflection events; fiber optic connectors, breaks, and end points will cause light reflections, forming upward mutation reflection events, while fiber bending and splicing will increase fiber attenuation, causing downward mutations, forming non-reflection events Through data analysis, find the abrupt point of the curve, determine the fiber event points such as fiber head end, tail end, joint, fusion splicing, etc., by comparing with the reference data, the change of attenuation data, determine the operating status of the optical cable, and analyze the breakage of the optical fiber and cable The point distance realizes the real-time online accurate and fast location of the fault point of optical fiber and optical cable.

In the above-mentioned embodiments of the present invention, the coupling unit 3 includes a coupler for coupling the signal light and monitoring light and sending them to the optical transmission medium, and a directional coupler. The directional coupler has three ports, wherein the monitoring light generates The unit 2 is connected to the first port of the directional coupler, the coupler is connected to the second port of the directional coupler, the signal processing unit 4 is connected to the third port of the coupler, and the The optical signal input from one port is output from the second port, and the optical signal input from the second port is output from the third port.

In the embodiment of the present invention, the three-port directional coupler adopted by the directional coupler, the optical signal input from the first port in the three-port directional coupler is output from the second port, that is, the monitoring light generated by the monitoring light generating unit 2 is output from the second port. After the first port is input, it is output to the coupler from the second port; and the optical signal input from the second port in the three-port directional coupler is output from the third port, that is, after the reflected light is separated by the coupler, The reflected monitoring light is input through the second port and then output to the signal processing unit 4 through the third port. And in the specific embodiment of the present invention, the coupler used to couple the signal light and monitor light to the optical transmission medium after sending to the optical transmission medium adopts a 3dB coupler, and the better splitting ratio is 0.5, but it is not limited to this value. And components for monitoring light are applicable in the embodiments of the present invention.

In the embodiment of the present invention, the above-mentioned three-port directional coupler can make the monitoring light generated by the monitoring light generating unit 2 and the reflected monitoring light independent of each other, and the reflected monitoring light can be separated from the third port, which is convenient for reflection Analyze and process the returned monitoring light to improve work efficiency.

In the above-mentioned embodiment of the present invention, as shown in FIG. 2, the above-mentioned transmission device further includes:

The branch unit 5 is used for uplink transmission or downlink transmission of the service signal carried by the signal light.

The main control cross-connect unit 6 is configured to dispatch the service signal obtained through the branch unit 5 to the line unit 1, and the main control cross-connect unit 6 is respectively connected to the branch unit 5 and the line unit 1 .

In the embodiment of the present invention, the service signal carried by the signal light is transmitted uplink or downlink to the main control cross unit 6 through the branch unit 5, and then the service signal is dispatched to the line unit 1 through the main control cross unit 6, The signal light generated by the line unit 1 is used to transmit various services and realize network intercommunication.

Further, in the specific transmission device of the present invention, the branch unit 5 is a service up-and-down board, and the main control cross-connect unit 6 is a main control cross-connect function board; but it is not limited thereto, all branch units that can realize the 5 and the specific hardware for the functions of the master cross-connect unit 6 are applicable in the embodiment of the present invention, and both can achieve the same beneficial effect.

In the above embodiments of the present invention, in order to prevent the reflected signal light from returning to the line unit 1 without affecting the accuracy of the service signal carried by the signal light, the line unit 1 includes:

A signal optical module connected to the main control cross-connect unit, configured to receive a service signal scheduled by the main control cross-connect unit, and generate signal light carrying the service signal;

The isolator connected with the signal light module is used to block the reflected signal light so that the signal light can be transmitted in one direction.

In a specific embodiment of the present invention, the monitoring light generating unit 2 is a fiber pulse laser, but it is not limited to this device, and other devices capable of generating light are applicable in the embodiments of the present invention.

In the foregoing embodiments of the present invention, as shown in FIG. 3 , the signal processing unit 4 includes:

A photodetector 40, connected to the third port of the directional coupler, for receiving the monitoring light reflected from the optical transmission medium, and performing photoelectric conversion on the reflected monitoring light to obtain an electrical signal;

An amplifier 41 connected to the photodetector 40 is used to amplify the electrical signal obtained by the photodetector 40;

The analog-to-digital converter 42 connected to the amplifier 41 is used to perform analog-to-digital conversion on the electrical signal amplified by the amplifier to obtain a digital signal;

The signal processor 43 connected to the analog-to-digital converter 42 is configured to perform signal processing and analysis on the digital signal to obtain the breakpoint position of the optical transmission medium.

In the embodiment of the present invention, in order to accurately obtain the breakpoint position of the optical fiber and optical cable, the reflected monitoring light must be converted into an electrical signal for analysis, but it is not limited to this. With the development of technology, the reflected optical signal The method that the analysis can also obtain the breakpoint position of the optical fiber and the optical cable is also applicable in the present invention. In the specific embodiment of the present invention, utilize photodetector 40 to carry out photoelectric conversion on the monitoring light reflected back, obtain electric signal; And because this electric signal is relatively weak, in order to facilitate analysis, must use amplifier 41 to amplify above-mentioned electric signal, What then obtains is the analog signal, and then uses an analog-to-digital converter A/D42 to carry out analog-digital conversion to the above-mentioned analog signal, obtains a digital signal; Finally, carry out the distribution processing of the above-mentioned digital signal along the time axis as required, and optical fiber, Analyze the reflection events and non-reflection events of the optical fiber cable to find out the breakpoint position of the optical fiber and optical cable.

The distance of the breakpoint of optical fiber and optical cable is related to time, specifically: all the time from transmitting the pulse to receiving the reflected pulse, and then determining the propagation speed of light in the optical fiber, the distance can be calculated.

The following formula describes the measured distance

d=(c*t)/(2*n) (2)

where c is the speed of light in vacuum, t is the total time from pulse emission to reception (two-way), and n is the refractive index of the fiber. Since there is an additional fiber of 500m between the fiber pulse laser and the directional coupler in this invention, the real physical distance D=d-500m

Further, in the specific embodiment of the present invention, the photodetector 40 is a PTN tube or an avalanche photodiode APD, but not limited thereto, other devices capable of converting optical signals into electrical signals are applicable in the embodiments of the present invention, and can achieve the same beneficial effect.

In the above-mentioned embodiments of the present invention, the signal processor 43 performing signal processing and analysis on the analog signal specifically includes:

Step 01, performing time-axis distribution processing on the digital signal;

Step 02, analyzing reflection events and non-reflection events according to the distribution of the time axis of the digital signal, and comparing them with reference data;

Step 03: Determine the operating state of the optical transmission medium according to the comparison result, and calculate the breakpoint distance of the optical transmission medium if there is a breakpoint in the optical transmission medium.

In the above-mentioned embodiment of the present invention, as shown in FIG. 2, the signal processing unit 4 is also connected to a monitoring and display unit 7 through the main control cross-connect unit 6, and the monitoring and display unit 7 is used to location warning message.

In the embodiment of the present invention, the monitoring and display unit 7 can display the position of the breakpoint of the optical fiber and optical cable in alarm modes such as graphics, data, and sound. The way of flashing reminds the staff that there is a problem with the optical fiber and the optical cable and needs to be solved; it can also be the sound of the alarm to remind the staff; it can also be expressed more vividly with graphics, but it is not limited to these methods, other methods can achieve the alarm effect The methods are applicable in the embodiments of the present invention.

In the above embodiments of the present invention, in order to fully and intuitively connect the running status and basic information of the optical fiber and cable, the monitoring and display unit 7 is also connected to a pipeline resource system for configuring and changing the information of the optical transmission medium.

Among them, the optical cable facility information is imported or manually entered into the optical cable pipeline system database through the completion data of the optical cable, including information such as marker stones, man wells, joints, poles, etc., as well as distance information and physical street information of each section of optical cable. The measurement accuracy of the existing optical time domain reflectometer based on the principle of Rayleigh scattering and Fresnel reflection of light can reach the meter level. The present invention is also based on the principle of Rayleigh scattering and Fresnel reflection of light. The distance accuracy of its measurement It can also be accurate to the meter level, that is, the measurement of the present invention is accurate, and the breakpoint of the optical fiber or optical cable can be accurately located between two specific wells or two benchmarks, which reflects the accuracy of the transmission device of the present invention.

Below in conjunction with Fig. 4, the specific execution steps of the transmission device of the present invention are described as follows:

Assume that optical fibers and optical cables are used to transmit optical signals between two transmission devices 001 and 002 of the present invention, wherein the line unit 1 in the embodiment of the present invention is composed of the signal optical module and isolator in Figure 4; the monitoring light generation unit 2 It is the monitoring optical module in Fig. 4; the coupler unit 3 is composed of the coupler and the directional coupler in Fig. 4; the signal processing unit is composed of the photodetector, the amplifier, the A/D converter and the signal in Fig. 4 It consists of a processor; the branch unit is the service processing board in Figure 4; the main control crossover unit is the main control crossover function board in Figure 4; the monitoring and display unit 7 is the network management computer in Figure 4, and the specific execution steps are as follows:

Step 1, the wavelength used by the signal optical module carrying the service at the transmission device 001 site is generally 1310nm or 1550nm (Note: the service signal is obtained through the tributary unit, and then the service signal is dispatched to the signal optical module through the main control cross-connect unit generated signal light). The monitoring light is generated by the monitoring optical module, and its wavelength can be selected as a wavelength different from that of the information signal, such as 1490nm or 1510nm. In the present invention, the monitoring optical module is selected as a fiber pulse laser. In order to deal with the front-end blind area, the present invention adds 500m of additional optical fiber between the fiber pulse laser and the directional coupler.

Step 2, the monitoring light pulse generated by the fiber pulse laser passes through the directional coupler and then is transmitted to the coupler. The purpose of using the directional coupler here in the present invention is to separate the reflected light from another channel, and the coupler uses light splitting A coupler with a ratio of 0.5.

Step 3: The light carrying the service signal passes through the directional isolator and then is transmitted to the 3dB coupler. The directional isolator blocks the reflected light.

Step 4: The signal light and monitoring light pulses carrying the business pass through the coupler and then enter the transmitting end of the optical fiber, realizing real-time online monitoring of the optical fiber and optical cable without switching the monitoring fiber core without affecting the service use.

Step 5, the light pulse is transmitted along the optical fiber. Due to the inherent characteristics of the fiber material, the light pulse will produce Rayleigh scattering in the fiber, and part of the light will return to the incident end along the fiber. When the optical pulse transmitted along the optical fiber meets the optical fiber connection device, optical fiber breakpoint, optical fiber end point, etc., a Fresnel reflection will occur.

Step 6, the monitoring light of Rayleigh scattering and Fresnel reflection carrying the power of the laser at each point of the optical fiber and optical cable will return to the coupler along the original optical fiber, and then output to the photodetector through the coupler, where The photodetector can be selected as a photodiode PIN or an avalanche photodiode APD.

In step 7, the photodetector performs photoelectric conversion on the received reflected signal, and converts it into an electrical signal.

Step 8, the converted electrical signal is amplified by the amplifier and sent to the A/D module.

In step 9, the A/D module performs analog-to-digital conversion on the amplified electrical signal, and converts it into a digital signal.

Step 10, the signal processing module distributes the collected data results along the time axis according to the needs, and analyzes the reflection events and non-reflection events of the optical fiber and optical cable. The optical fiber connector, breakage and end point will cause light reflection. A reflection event with an upward mutation is formed, and the bending and splicing of the fiber will increase the attenuation of the fiber, causing a downward mutation and forming a non-reflection event. Find the mutation point of the curve through data analysis, and determine the fiber head end, tail end, connector, Optical fiber event points such as fusion splicing. By comparing with the reference data and the change of attenuation data, the running state of the optical cable is determined, and the breakpoint distance of the optical fiber and optical cable is analyzed.

The speed of monitoring light propagating in the optical fiber is about 100000KM/s, so the time for the monitoring light pulse of the device and system of the present invention to propagate along the optical fiber for a distance of 10KM (including round trip) is about 10-4s, so the time for the present invention to locate the fault of the optical cable It mainly depends on the processing process of the electrical signal, and the time of this process is controlled in the order of seconds. Therefore, the optical cable detection system of the present invention has the feature of fast positioning.

Step 11, the signal processor outputs the processed data to the monitoring and display unit through the main control cross-connection unit in the form of trajectory graphics, where the monitoring and display unit refers to a unified and centralized system for all transmission network equipment, systems and optical cables monitor.

Step 12, the monitoring and display unit displays the physical location of the entire section of optical fiber according to the resource database information of the optical cable pipeline system, and displays the location of breakpoints of the optical fiber and optical cable in the form of alarms such as graphics, data, and sound. The optical cable facility information is imported or manually entered into the optical cable pipeline system database through the completion data of the optical cable, including information such as marker stones, man wells, joints, poles, etc., as well as distance information and physical street information of each section of optical cable. The measurement accuracy of the existing optical time domain reflectometer based on the principle of Rayleigh scattering and Fresnel reflection of light can reach the meter level. The present invention is also based on the principle of Rayleigh scattering and Fresnel reflection of light. The distance accuracy of its measurement It can also be accurate to the order of meters, that is, the device and system of the present invention measure accurately, and can accurately locate the breakpoint of the optical fiber or optical cable between two specific wells or two benchmarks.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (9)

1. A transmission device, comprising: a line unit for generating signal light for carrying service signals; it is characterized in that the transmission device also includes a monitoring light generation unit, a coupling unit and a signal processing unit, The monitoring light generating unit is used to generate monitoring light for detecting the optical transmission medium; The coupling unit is configured to couple the signal light and the monitoring light to the optical transmission medium, and send the reflected monitoring light received from the optical transmission medium to the signal processing unit; wherein, from the The reflected monitoring light received by the optical transmission medium includes: Fresnel reflection light generated due to the reflection of the section of the optical transmission medium and the connection between the optical transmission medium and the optical transmission medium, and Rayleigh scattering in the optical transmission medium Light; The signal processing unit is configured to perform signal processing and analysis on the monitoring light returned by the coupling unit, and obtain the breakpoint position of the optical transmission medium; wherein, The signal processing unit is specifically used to perform signal processing and analysis on the Rayleigh scattering and Fresnel reflection monitoring light carrying the power of the laser at each point of the optical transmission medium to determine the operating state of the optical transmission medium and the optical transmission medium. The breakpoint position of ; among them, The coupling unit includes a coupler and a directional coupler for coupling the signal light and monitoring light to an optical transmission medium, and the directional coupler has three ports, wherein the monitoring light generating unit is connected to the The first port of the directional coupler is connected, the coupler is connected to the second port of the directional coupler, the signal processing unit is connected to the third port of the coupler, and the input from the first port an optical signal is output from the second port, and an optical signal input from the second port is output from the third port; The signal processing unit includes: a photodetector, connected to the third port of the directional coupler, for receiving the monitoring light reflected from the optical transmission medium, and performing photoelectric conversion on the reflected monitoring light to obtain an electrical signal; an amplifier connected to the photodetector, used to amplify the electrical signal obtained by the photodetector; An analog-to-digital converter connected to the amplifier, configured to perform analog-to-digital conversion on the electrical signal amplified by the amplifier to obtain a digital signal; a signal processor connected to the analog-to-digital converter, configured to perform signal processing and analysis on the digital signal, and obtain the breakpoint position of the optical transmission medium; The signal processor performing signal processing and analysis on the digital signal specifically includes: performing time-axis distribution processing on the digital signal; Analyzing reflective events and non-reflective events according to the distribution of the time axis of the digital signal, and comparing them with reference data; Determine the operating state of the optical transmission medium according to the comparison result, and calculate the breakpoint distance of the optical transmission medium if there is a breakpoint in the optical transmission medium. 2. The transmission device according to claim 1, further comprising: A branch unit, used for uplink transmission or downlink transmission of the service signal carried by the signal light; The main control cross-connect unit is configured to dispatch the service signal obtained through the branch unit to the line unit, and the main control cross-connect unit is respectively connected to the branch unit and the line unit. 3. The transmission device according to claim 2, wherein the line unit comprises: A signal optical module connected to the main control cross-connect unit, configured to receive a service signal scheduled by the main control cross-connect unit, and generate signal light carrying the service signal; The isolator connected with the signal light module is used to block the reflected signal light so that the signal light can be transmitted in one direction. 4. The transmission device according to claim 1, wherein the monitoring light generating unit is a fiber pulse laser. 5. The transmission device according to claim 1, wherein the photodetector is a photodiode PIN or an avalanche photodiode APD. 6. The transmission device according to claim 2, characterized in that, the branch unit is a service up-and-down board. 7. The transmission device according to claim 2, wherein the main control cross-connect unit is a main control cross-connect function board. 8. The transmission device according to claim 2, wherein the signal processing unit is further connected to a monitoring and display unit through the main cross-connection unit, and the monitoring and display unit is used to A warning message is issued at the breakpoint position. 9. The transmission device according to claim 8, wherein the monitoring and display unit is further connected to a pipeline resource system for configuring and changing the information of the optical transmission medium.