Disturbance sensor for interference-type optical fiber and sensing method thereof

Abstract

The present invention relates to an interference-type disturbance sensor using an optical fiber, and a sensing method thereof. After an optical signal output from an optical signal generation unit is divided and sent along optical paths of mutually different lengths, a combined sensed optical signal is output through the sensed optical fiber. The sensed optical signals returning from the sensed optical fiber are divided and sent along the optical paths having the different lengths to be combined to generate a disturbance sensing optical signal. Therefore, whether an intruder has intruded, the location of an intrusion, and the target of the intrusion can be determined with greater ease.

Description

technical field [0001] The present invention relates to a detection device using an optical fiber, and more specifically, to a detection system capable of detecting external disturbance applied to a detection optical fiber with high sensitivity using an interferometer. Background technique [0002] In general, in monitoring damage caused by intrusion, damage, aging, or impact, many personnel and costs are required if manpower is used. Moreover, when the monitoring personnel are careless or temporarily leave their positions, it may cause failure in vigilance, and, in bad weather or nighttime when the line of sight is not complete, it may be difficult to monitor the intrusion by human power. [0003] Therefore, for the purpose of an auxiliary unit for the monitoring of such military security or important facilities by means of manpower, or for the unmanned monitoring of less important facilities, the necessity of an automatic monitoring system using sensors has arisen. For thi...

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Problems solved by technology

However, in order to improve this problem, if a thick optical fiber with enhanced strength is used, it will be easily found by intruders, or on the contrary, it will continue to break when it should be broken, which leads to another problem that it is difficult to form a proper intrusion detection.

In addition, once the optical fiber is disconnected, it is impossible to reuse it until it is repaired by specialized personnel, and because there is no automatic alarm function or reporting function, there is no practical possibility at all

[0009] On the other hand, the method of monitoring the intensity of emitted light based on the pressure exerted by intruders passing through special optical fibers can be used in a safer underground system, but in this case, the intensity of reflected light changes very little, Difficult to use as an effective human detection sensor

In addition, the method of detecting the interference of reflected light in the two refractive index warning surfaces based on the change of the refractive index of the optical fiber by using OTDR etc. is difficult to achieve common use because the sensitivity of the sensor decreases and the price of the sensor system is too high.

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