CN1305243C - Testing method and apparatus for automatic light power reducing process time of dense wave divided multiplexing system - Google Patents

Abstract

A test method related to the automatic optical power reduction process time of the dense wavelength division multiplexing system in the field of optical communication. In the test of the optical power reduction process time, the relevant activation time test involves the test optical amplifier and response Optical amplifier, when the optical amplifier is at the starting point, the interrupt signal is set to start the counter to count through the CPU control system, when the response optical amplifier is at the response point, the interrupt signal is set to stop the counter counting through the CPU control system, and according to the counter value Reflecting the test result of the corresponding optical power reduction process time; its test device, including a power supply, is characterized in that: it also includes a small CPU system, a control processing module, and at least two measuring optical amplifiers involved in the relevant activation time test A channel signal detection and processing module respectively connected to the response optical amplifier; the invention is simple, easy to use, and low in cost, and provides support for engineering technology.

Description

Test method and apparatus for automatic optical power reduction process time of dense wavelength division multiplexing system

technical field

The invention relates to optical communication technology, in particular to a test method and device for automatic optical power reduction process time of a dense wavelength division multiplexing system in the field of optical communication.

Background technique

In an optical communication system, accidents such as optical cable cutoff, equipment failure, or optical connector pull-out will result in loss of optical power. For the sake of human eye safety, the loss of optical power in an optical transmission section of the main optical channel Under the circumstances, the system needs to provide automatic optical power reduction APR or automatic laser shutdown ALS process. In order to restore the system easily after the link is reconnected, it is necessary to consider implementing an automatic or manual restart process at the same time.

When it is detected that the optical signals of all the main optical channels are lost, the dense wavelength division multiplexing system DWDM starts the APR process, and closes all the amplifiers in the affected optical transmission section OTS; when the signal is restored, the optical amplifier can be restored. Work. This can ensure that the optical power in the fiber is within the requirements of the safety level when it is turned off.

The APR/ALS technical process of the optical communication system must run continuously, ie cannot be shut down, otherwise the risk level will be too high.

Some time constant test methods of the traditional APR process use oscilloscopes as an auxiliary means to test the time constant of the APR process. The shortcomings of this method will bring randomness of test results, complex test process, and different oscilloscopes. The difference is also related to the operator. In addition, this method requires some auxiliary circuits to convert and process optical signals to electrical signals.

Contents of the invention

The object of the present invention is to provide a test method and device for automatic optical power reduction process time of dense wavelength division multiplexing system, so as to overcome the problems of low test reliability and complicated operation in the prior art.

The technical scheme adopted in the present invention is: the test method of the automatic optical power reduction process time of this dense wavelength division multiplexing system, it is characterized in that: it adopts the following steps:

A. In the test of the optical power reduction process time, for the start-up optical amplifier and the response optical amplifier involved in the relevant activation time test, when the start-up optical amplifier is at the start point, an interrupt signal is set to start the counter through the CPU control system. count;

B. When the response optical amplifier is at the response point, set the interrupt signal to stop the counter counting through the CPU control system, and reflect the test result of the corresponding optical power reduction process time according to the counter value. The test results are divided into timeout, failure and success.

The relevant activation time is the deactivation time of the automatic optical power reduction process. The starting optical amplifier and the responding optical amplifier are respectively the next-level optical amplifier and the corresponding upper-level optical amplifier in the same transmission line. When the first-level optical amplifier receives the loss of continuity signal (LOC-OTS) in the optical transmission section, it is the starting point, and when the output optical power of the upper-level optical amplifier is reduced to a safe optical power value, it is the response point;

The relevant activation time is the deactivation time of the equipment, and the measuring optical amplifier and the responding optical amplifier are respectively the receiving optical amplifier and the corresponding reverse transmission optical amplifier in the transmission line site, and the receiving optical amplifier receives the optical transmission section The loss of signal continuity signal (LOC-OTS) is the starting point, and the output optical power of the reverse transmission optical amplifier is reduced to a safe optical power value is the response point.

The relevant activation time is the activation time of the automatic optical power reduction process. The starting optical amplifier and the responding optical amplifier are respectively the next-level optical amplifier and the corresponding upper-level optical amplifier in the same transmission line. When the stage optical amplifier receives the restart pulse, it is the measuring device, which is respectively the receiving optical amplifier in the transmission line site and the corresponding reverse transmission optical amplifier. When the receiving optical amplifier receives the restart pulse, it is the starting point, so The response point is when the above-mentioned reverse transmission optical amplifier sends signals normally.

In the step B, when the responding optical amplifier cannot complete the automatic optical power reduction process action, the counter cannot stop counting, and if the value of the counter exceeds the preset timeout value, an alarm prompt will be displayed.

The principles and beneficial effects of the present invention are: the basic principle of the APR process, as shown in Figure 1, is a bidirectional optical transmission system, the first optical amplifier 100, the second optical amplifier 101, the third optical amplifier 102 and the fourth optical amplifier The optical amplifier 103 constitutes a line amplification optical transmission section that includes two sites, so for this optical transmission section, the first optical amplifier 100 and the fourth optical amplifier 103 are used as sending ends, and the second optical amplifier 101 and the third optical amplifier 102 as the receiving end. When the optical fiber at point A 104 is broken, the second optical amplifier 101 first detects that the signal continuity of the optical transmission section is lost LOC-OTS, which will cause the output power of the fourth optical amplifier 103 to decrease; also cause the third optical amplifier 102 to appear LOC -OTS, so that the power of the first optical amplifier 100 is reduced. In this way, it is ensured that the optical power on the section of optical fiber at point A 104 where the transmission failure occurs is at a safe level. When A point 104 fiber break fault is recovered, the first optical amplifier 100 and the fourth optical amplifier 103 all return to the normal power level, then the second optical amplifier 101 and the third optical amplifier 102 also automatically return to the normal power level, and the relevant activation Time includes:

1. APR process deactivation time: when the fiber at point A 104 breaks, from the second optical amplifier 101 receiving LOC-OTS to the first optical amplifier 100 output optical power is reduced to a safe optical power value, this period is the APR process deactivation Activation time.

2. Device deactivation time: When the fiber at point A 104 breaks, the time from the second optical amplifier 101 receiving LOC-OTS to the fourth optical amplifier 103 output optical power is reduced to a safe optical power value, this period is the device deactivation time .

3. Activation time of the APR process: if the fiber at point A recovers, the period from when the second optical amplifier 101 receives a restart pulse to when the first optical amplifier 100 normally sends a signal is the APR process activation time.

4. Device activation time: the period from when the second optical amplifier 101 receives the restart pulse to when the fourth optical amplifier 103 normally sends a signal is the device activation time. Among them, for the safe power after APR reduction, in the OTS affected by APR shown in Figure 1, the power at all optical output ends drops below 0dBm, but it will not cause other alarms in the downstream, that is, only the affected OTS end It is known; for the restart pulse power level, the restart pulse levels sent by the first optical amplifier 100 and the fourth optical amplifier 103 should be less than 10dBm, but not too small. For the second optical amplifier 101 and the third optical amplifier 102, it must be ensured that the optical power of the transmitted restart pulse after line attenuation is still greater than the LOC-OTS decision threshold, and the restart pulse is different from the normal working signal. In the restarting process, as shown in Figure 1, when the faulty OTS segment connection is restored, manual or automatic restarting can be used to restore the transmission in the OTS segment.

In the present invention, adopt CPU control system to carry out timing to the starting point and the response point of relevant activation time in the test of optical power reducing process time, can test each time constant of DWDM transmission system APR process conveniently and quickly, its test The consistency and accuracy are greatly improved, and the degree of test automation is also improved accordingly, which saves manpower and material resources, thereby improving work efficiency. The invention makes the APR process-related time constant test simple, easy to use, and low in cost, providing support for engineering technology .

Description of drawings

Figure 1 is a block diagram of the APR function of the DWDM system;

Fig. 2 is a schematic block diagram of the testing device of the present invention;

Fig. 3 is a schematic flow chart of the test main control process of the present invention;

Fig. 4 is a schematic diagram of the timer interrupt service flow diagram in the testing process of the present invention;

Fig. 5 is a schematic diagram of channel 1 interrupt service flow in the testing process of the present invention;

Fig. 6 is a schematic diagram of channel 2 interrupt service flow in the testing process of the present invention;

Fig. 7 is the schematic diagram of the circuit structure of the testing device of the present invention;

Fig. 8 is a schematic diagram of the application and implementation of the present invention;

Fig. 9 is a schematic diagram of the application and implementation of the present invention;

Fig. 10 is a schematic diagram of the application and implementation of the present invention;

Fig. 11 is a schematic diagram of the implementation of the application of the present invention.

Detailed ways

Below according to accompanying drawing and embodiment the present invention will be described in further detail:

The present invention adopts the following steps to test the relevant activation time of the optical power reduction process time:

A. In the test of the optical power reduction process time, for the start-up optical amplifier and the response optical amplifier involved in the relevant activation time test, when the start-up optical amplifier is at the start point, an interrupt signal is set to start the counter through the CPU control system. Count; associated activation times include automatic optical power reduction process deactivation time, device deactivation time, automatic optical power reduction process activation time, and device activation time.

B. When the responding optical amplifier is at the responding point, set an interrupt signal to stop the counter counting through the CPU control system, and reflect the test result of the corresponding optical power reduction process time according to the counter value.

In the above test, when testing the deactivation time of the automatic optical power reduction process, the initiating optical amplifier and the responding optical amplifier are respectively the lower-level optical amplifier and the corresponding upper-level optical amplifier in the same transmission line. The starting point is when the first-level optical amplifier receives the LOC-OTS, and the response point is when the output optical power of the upper-level optical amplifier decreases to a safe optical power value.

When testing the deactivation time of the equipment, the starting optical amplifier and the responding optical amplifier are respectively the receiving optical amplifier and the corresponding reverse transmission optical amplifier in the transmission line site, and the receiving optical amplifier is the starting point when receiving the LOC-OTS , the response point is when the output optical power of the reverse transmission optical amplifier decreases to a safe optical power value.

When testing the activation time of the automatic optical power reduction process, the starting optical amplifier and the responding optical amplifier are respectively the lower-level optical amplifier and the corresponding upper-level optical amplifier in the same transmission line, and the lower-level optical amplifier receives The starting point is when the pulse is restarted, and the response point is when the upper-stage optical amplifier sends signals normally.

When testing the activation time of the equipment, the starting optical amplifier and the responding optical amplifier are respectively the receiving optical amplifier and the corresponding reverse transmission optical amplifier in the transmission line site, and the receiving optical amplifier is the starting point when receiving the restart pulse, The response point is when the reverse transmission optical amplifier normally sends signals.

As shown in Fig. 2, the present invention can adopt this testing device, and it comprises power supply 204, CPU small system 200, control processing module 203, and at least two and related activation time test involves measuring optical amplifier and responding optical amplifier Respectively connected channel signal detection processing modules, the channel signal detection processing module includes a channel 1 signal detection processing module 201 and a channel 2 signal detection processing module 202, and the channel 2 signal detection processing module 202 and the channel 1 signal detection processing module 201 are respectively Detect the starting point and response point, and send the relevant interrupt signal to the small CPU system, and the small CPU system sends corresponding instructions to the control processing module. The channel signal detection and processing module includes an input terminal, a photoelectric conversion signal amplification circuit, a comparator interrupt generation circuit and a comparison reference level generation circuit, which are connected in sequence. The comparison reference level generation circuit is controlled by the CPU small system and sends The interrupt generating circuit sends out comparison reference level information, and generates an interrupt control signal by comparing the comparator circuit with the reference decision level. As shown in FIG. 503, the first comparator interrupt generating circuit 505 and the comparison reference level generating circuit 507, the channel 2 signal detection processing module 202 includes an input terminal 502, a second photoelectric conversion signal amplifying circuit 504, a second comparator interrupt generating circuit 506 and a comparison Reference level generating circuit 507.

For example, to test the deactivation time of the automatic optical power reduction process of an optical transmission section, as shown in FIG. % of the optical signal to the second optical amplifier 101, and the other 50% of the optical signal to channel 2 of the testing device of the present invention.

For the sending end, the optical signal from the output detection port 601 of the first optical amplifier 101 is directly connected to channel 1 of the testing device of the present invention, and the output optical power of the first optical amplifier 101 is indirectly detected.

The starting optical amplifier is the second optical amplifier 101, and the responding optical amplifier is the first optical amplifier 100. When the second optical amplifier 101 receives the LOC-OTS, it is the starting point, and the output optical power of the first optical amplifier 100 is reduced to a safe level. When the optical power value is the response point.

In this way, in the testing device of the present invention, the input terminal 502 in the channel 2 signal detection processing module 202 obtains the detection signal from the corresponding optical transmission section through the optical coupler 602, and detects the LOC-LOS signal received by the second optical amplifier 101; The input terminal 501 in the channel 1 signal detection processing module 201 detects the output optical power of the first optical amplifier 101 through the output detection port 601 of the first optical amplifier 101 .

The basic process of the test is as follows: as shown in Figure 3, Figure 4, Figure 5 and Figure 6, firstly, the software initialization of the small CPU system is completed, and the initialization of timers, interrupt services, and global important parameters are completed. After the initialization is finished, if you need to set the control parameters, you can also set them at this time. Then judge the "test status of this test". This parameter is controlled by the timer interrupt service program. It has four values, namely: success, failure, timeout, and initial state. As shown in Figure 3, if it is in the first three states, the corresponding test result will be given, and in the successful state, the result of this test will also be given at the same time. Then re-initialize the relevant parameters: "counter value", "counter state", "this test state", and finally the main control returns to judge the "this test state" and execute the main program repeatedly. If it is the initial state, also get back to the main program to judge "this test state" and repeat the main program.

When the "test status of this test" is success, timeout, or failure, the test result needs to be given. The test result unit here is seconds. The calculation method is: calculated according to the "counter value" and the timing constant of the timing interrupt. If the timing constant of the timer interrupt service program is 1 ms, and the "counter value" is N, then the test result provided by the present invention is N/1000 seconds.

The interrupt service process assigns a value to "this test state", which is assigned according to the state of the "count flag" and the counter value. As shown in Fig. 4, Fig. 5 and Fig. 6, the state of the "counting flag" has three values, which are: state 1, state 2, and initial state. If the current state is 1, the counter counts up by 1, and then judges whether the counter exceeds the preset value. If it exceeds the preset value, the assignment of "this test status" will time out, otherwise the value of "this test status" will not be changed, and then the interrupt will return. If the current state is 2, the counter stops counting, and then judges the counter value. According to whether the value of the counter exceeds the preset value, whether it is equal to 0, or whether it is between 0 and the over-limit value, set the "this test state" assignment to Timeout, failure, success, and interrupt return. The counter state is controlled with the channel 1 interrupt service routine and channel 2 interrupt service routine in the subroutine. When the channel 1 interrupt service routine is triggered, the "count flag" is set to state 1; when the channel 2 interrupt service routine is triggered, the "count flag" is set to state 2.

The process of testing the deactivation time under normal circumstances is as follows: the test device of the present invention starts, and the main control process starts to run. As shown in Figure 4, the timer interrupt service process is executed once at regular intervals, and the value of the "counting flag" is checked. As shown in Figure 8, when the optical fiber break point 603 is broken, the channel 2 signal detection processing module 202 detects LOC-LOS, that is, when it is at the starting point, it starts to execute the channel 1 interrupt service process in Figure 5, and starts the counter to perform count. The "Count Flag" is set to state 1. When the first optical amplifier 100 enters the APR state, its output optical power drops below the safe optical power value, that is, when it is at the response point, the channel 1 signal detection processing module 201 detects that the output optical power of the first optical amplifier 101 is lower than the set value. Set the threshold value, start to execute the channel 2 interrupt service process in Figure 6, stop the counter counting, and set the "counting flag" to state 2. The timing interrupt service process in Fig. 4 sets "this test status" according to the "count flag". As shown in Figure 3, in the main control process, the situation of this test is obtained according to the "current test status", and the test result is given.

When the response optical amplifier cannot complete the automatic optical power reduction process action, the counting of the counter cannot be stopped. If the value of the counter exceeds the preset timeout value, that is, when the first optical amplifier 100 fails to complete the APR action, it cannot enter the APR state, the control flow cannot stop the counting of the counter, and if the application judges that the value of the counter exceeds the preset timeout value, an alarm prompt will be displayed, indicating that the APR function is implemented incorrectly; in addition, although the first optical amplifier 100 can complete the APR action, if When the read counter value exceeds the preset value, a corresponding alarm prompt will also be reported.

In the test device of the present invention, a communication interface circuit 508 may also be included to provide standard communication interfaces, such as serial ports, USB ports, Ethernet ports, GPIB ports, and the like.

The above description reflects the process of testing the deactivation time of the automatic optical power reduction process. For testing the deactivation time of the equipment, the activation time of the automatic optical power reduction process, and the test of the device activation time, the process is similar to the above, and will not be repeated here. .

As shown in Figure 9, when the 601 line amplifier LA has no output detection port, the output port of the first optical amplifier 100 is directly used, and the output of the first optical amplifier 100 is connected to the input of the second 50/50 optical coupler 701, and the second 50 One path of the /50 optical coupler 701 is output to the channel 1 of the test device of the present invention, and the other is to the main optical path. The receiving end is similar to that in Figure 8, and the channel 1 signal detection processing module 201 is detected by the second 50/50 optical coupler 701 The output optical power of the first optical amplifier 101 is tested for the deactivation (or activation) time of the APR. The testing principle and process are the same as those described above, and will not be repeated here.

As shown in Figure 10, when the network element where the first optical amplifier 100 is located and the second optical amplifier 101 are in two cities with a certain distance, the channel signal detection processing module is connected to an adjustable optical attenuator to obtain a detection signal, adjustable The optical attenuator 801 is connected to the channel 2 signal detection and processing module, so that the optical power entering the channel 2 of the test device of the present invention is the same as the optical power entering the second optical amplifier 101. As for its specific structure, testing principle and process are the same as the foregoing, here I won't repeat them here.

As shown in Figure 11, the input optical power of the second optical amplifier 101 and the output optical power of the fourth optical amplifier 103 are monitored by the channel 1 and the channel 2 of the test device of the present invention respectively, after the optical fiber fracture point 603 is broken, the channel 2 detects LOC-OTS, the fourth optical amplifier 103 performs the APR function, and the channel 1 detects that the output optical power of the fourth optical amplifier 103 is lower than the safe optical power value, which can be used to test the deactivation time of the equipment, and the test method and process are similar to the above , which will not be repeated here.

The test device of the present invention can be used independently, also can be used under the control of a PC or integrated into an optical communication tester for use.

Claims (2)

1. a kind of test method of dense wavelength division multiplexing system automatic optical power reduces process time, it is characterized in that: it adopts following steps: A. In the test of the optical power reduction process time, for the start-up optical amplifier and the response optical amplifier involved in the relevant activation time test, when the start-up optical amplifier is at the start point, an interrupt signal is set to start the counter through the CPU control system. count; B. When the response optical amplifier is at the response point, set the interrupt signal to stop the counter counting through the CPU control system, and reflect the test result of the corresponding optical power reduction process time according to the counter value. The test results are divided into overtime, failure and success; When the relevant activation time is the deactivation time of the automatic optical power reduction process, the starting optical amplifier and the responding optical amplifier are respectively the next-level optical amplifier and the corresponding upper-level optical amplifier in the same transmission line, and the described When the next-level optical amplifier receives the signal continuity loss signal in the optical transmission section, it is the starting point, and when the output optical power of the upper-level optical amplifier is reduced to a safe optical power value, it is the response point; When the relevant activation time is the device deactivation time, the starting optical amplifier and the responding optical amplifier are respectively the receiving optical amplifier and the corresponding reverse transmission optical amplifier in the transmission line site, and the receiving optical amplifier receives the optical transmission When the segment signal continuity loses signal, it is the starting point, and when the output optical power of the reverse transmission optical amplifier is reduced to a safe optical power value, it is the response point; When the relevant activation time is the activation time of the automatic optical power reduction process, the initiating optical amplifier and the responding optical amplifier are respectively the lower-level optical amplifier and the corresponding upper-level optical amplifier in the same transmission line, and the lower-level optical amplifier When the first-level optical amplifier receives the restart pulse, it is the starting point, and when the upper-level optical amplifier normally sends signals, it is the response point; When the relevant activation time is the equipment activation time, the starting optical amplifier and the responding optical amplifier are respectively the receiving optical amplifier and the corresponding reverse transmission optical amplifier in the transmission line site, and the receiving optical amplifier receives the restart pulse The time is the starting point, and the time when the reverse transmission optical amplifier normally sends the signal is the response point. 2. The test method for automatic optical power reduction process time of dense wavelength division multiplexing system according to claim 1, characterized in that: in the described step B, the described response optical amplifier cannot complete the automatic optical power reduction When the process is active, the counting of the counter cannot be stopped. If the value of the counter exceeds the preset timeout value, an alarm prompt will be displayed.

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