Continuous Time-Domain Measurement Method of Rayleigh Backscattered Light With Coherent Detection

This letter shows the results of continuous time-domain measurement of Rayleigh backscattered light. Experimental results show that we can measure the variation of the phase of the backscattered light from a specific point of the fibers where we applied sinusoidally varying stress at a frequency of 140 kHz. We expect that the method will find application to continuously measure the rapid variation of external perturbation in the time domain at a specific point in the fibers.