Abstract:

In order to solve the problem of locating underground personnel when the accident happens, a simple distributed vibration sensor system is proposed which employs an optical fiber ring interferometer having an additional sub-loop coupled with a main ring by a 3 dB coupler according to the advantages and disadvantages of communication system under mine. Comparing multiple responses of interfered beams by the lights travelling n times in the sub-loop, the proposed system can detect the position and the amplitude of acoustic vibration occurred in the main ring. By simplifying the calculation, the optical fiber vibration position obtained. The calculated values are compared with the actual value, it is showed that the system can detect the shock position very accurately with smaller error. When accident happened, miners strike the ground or wall to get vibration signal, it can detect the specific location of the miners providing a good basis for mine rescue.

Key words: distributed optical fiber positioning, sub-loop, interference, vibration, positioning