Long-distance programmable optical fiber cable loss distribution testing device and method

Abstract

The invention provides a long-distance programmable optical fiber cable loss distribution testing device and method. The long-distance programmable optical fiber cable loss distribution testing device comprises a first optical fiber coupler, a first optical fiber disc, a second optical fiber coupler, a second optical fiber disc, a third optical fiber coupler, a third optical fiber disc, an optical switch, an optical attenuator and a timer. The second optical fiber coupler, the second optical fiber disc, the third optical fiber coupler, the third optical fiber disc, the optical switch and the optical attenuator are connected in sequence, and the optical attenuator is connected with the second optical fiber coupler to form an optical fiber transmission loop; the first optical fiber coupler is connected with the second optical fiber coupler, and the first optical fiber disc is arranged between the first optical fiber coupler and the second optical fiber coupler; the first optical fiber coupler is also connected with a timer; the timer is connected with the optical switch. According to the invention, a timer capable of being triggered synchronously is designed, timing of the timer can be automatically synchronized with detection light pulses of the coherent optical time domain reflectometer, manual intervention is not needed, and the optical fiber cable distance and actual loss distribution within the range of 30 km to 20000 km can be simulated.

Description

technical field [0001] The disclosure belongs to the technical field of optical fiber and cable loss testing, and in particular relates to a long-distance programmable optical fiber and cable loss distribution testing device and method. Background technique [0002] Due to the advantages of large communication capacity, high transmission rate, small transmission loss, strong anti-electromagnetic interference and good confidentiality, optical fiber communication has been rapidly developed and widely used; submarine communication optical cables are mainly used for long-distance communication between offshore islands or across oceans , the communication distance is as short as hundreds of meters to tens of kilometers, as long as hundreds of kilometers to thousands of kilometers, and even longer than 10,000 kilometers; figure 2 As shown, since the submarine communication optical cable is a communication cable with a special structure, the transmitting and receiving lines are sep...

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Problems solved by technology

[0007] 1. Based on the method of "delay line and optical switch", the transmission delay of the detection signal in the communication link is simulated mainly through the delay effect of the optical fiber delay line, and the transmission distance is simulated in turn, and different delay sizes are selected through the optical switch To simulate different transmission distances, due to the limited delay time of optical fiber delay lines, usually several hundred microseconds, it is impossible to simulate distances of thousands of kilometers or more. In addition, this method cannot simulate the loss distribution of communication optical cables;

[0008] 2. Based on the method of "optical fiber circulator + optical switch", in the simulated optical cable link, since the two ports of the optical fiber circulator are respectively connected to the two output ports of the 2*2 fiber optic coupler, the optical fibers in these two channels All backscattered signals will return to the coherent optical time domain reflectometer through the 2*2 fiber coupler, resulting in signal aliasing, so the link loss cannot be simulated, and due to the use of optical amplifiers in the loop, it will return to the coherent optical time domain reflectometer. The signal strength of the time domain reflectometer is high, which will saturate the power of the detector at the receiving end, so that it cannot be tested normally;

[0009] 3. Based on the method of "optical switch + function generator", it mainly simulates the number of cycles of the detection optical pulse in the optical cable loop by setting the width and period of the output pulse of the function generator, in order to realize the long-distance optical cable link However, the maximum simulation distance of this device can only reach 1000km, and the simulation of longer distances cannot be realized. In addition, this method can only make the coherent optical time domain reflectometer receive the detection light pulse in the optical fiber transmission loop, and cannot receive the optical fiber transmission loop. The backscattering signal of the link, so it is impossible to realize the simulation test of the loss distribution of the optical cable link, and the strong detection light pulse enters the light receiving end of the optical time domain reflectometer through the fiber coupler, although there is a certain attenuation , but the power is still very strong, and the optical receiving end will also fail to test normally due to the power saturation of the detector

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