Fast Peak Searching Method for Brillouin Gain Spectrum Using Positive-Slope Inflection Point

Abstract

A Fast peak searching method for Brillouin gain spectrum (BGS) using positive-slope inflection point is proposed. In this method, the positive-slope inflection point of Brillouin gain spectrum is used to terminate the frequency scanning (FS) progress adaptively and determine the Brillouin frequency shift (BFS). The number of frequency scanning points and data acquisition time is effectively reduced. The basic measurement principle, algorithm, and performance evaluation are presented. Based on experimental results over 9.91km-long optical fiber, the measurement time by conventional FS method is 50.13s, whereas it is only 15.62s by fast peak searching method. Under the same hardware, RMSE of measured BFS is 0.67MHz, which is nearly the same as the results obtained by conventional FS method. When the signal-to-noise ratio at the end of optical fiber (<i>SNR</i>_E) is within a reasonable range (i.e., <i>SNR</i>_E &gt; 2.4dB), the proposed method can effectively save processing time. The measurement speed of fast peak searching method is increased by about three times than that of conventional FS method, nearly without the loss of measurement accuracy.