›› 2014, Vol. 23 ›› Issue (11): 110703-110703.doi: 10.1088/1674-1056/23/11/110703
郝蕴琦a, 叶青b, 潘政清b, 蔡海文b c, 瞿荣辉b
Hao Yun-Qi (郝蕴琦)a, Ye Qing (叶青)b, Pan Zheng-Qing (潘政清)b, Cai Hai-Wen (蔡海文)b c, Qu Rong-Hui (瞿荣辉)b
摘要: The digital coherent detection technique has been investigated without any frequency-scanning device in the Brillouin optical time domain reflectometry (BOTDR), where the simplex pulse codes are applied in the sensing system. The time domain signal of every code sequence is collected by the data acquisition card (DAQ). A shift-averaging technique is applied in the frequency domain for the reason that the local oscillator (LO) in the coherent detection is fix-frequency deviated from the primary source. With the 31-bit simplex code, the signal-to-noise ratio (SNR) has 3.5-dB enhancement with the same single pulse traces, accordant with the theoretical analysis. The frequency fluctuation for simplex codes is 14.01 MHz less than that for a single pulse as to 4-m spatial resolution. The results are believed to be beneficial for the BOTDR performance improvement.
中图分类号: (Fiber-optic instruments)