Phase Interrogation of Diaphragm-Based Optical Fiber Acoustic Sensor Assisted by Wavelength-Scanned Spectral Coding

IEEE Photonics Journal

Jiangshan Zhang¹  Xin Fu²  Xinyue Jiang²  Hao Liao²  Ping Lu²  Wenjun Ni²  Deming Liu² 

[1] Department of Electronics and Information Engineering, Huazhong University of Science and Technology, Wuhan, China;National Engineering Laboratory for Next Generation Internet Access System, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China;

关键词: Optical sensors;    optical fiber devices;    acoustic sensing;    signal demodulation;   

DOI  :  10.1109/JPHOT.2018.2827059

来源: DOAJ

【 摘 要 】

In this paper, we proposed a phase interrogation method for diaphragm-based interferometric optical fiber acoustic sensor based on the spectral coding process. The information of the sound wave is coded on the optical spectrum of the sensor head by wavelength scanning, which builds a map between time and wavelength. The acoustic signal can be reconstructed from the sound-encoded spectrum. The sound-induced phase variation of the sensor can be interrogated by comparing the sound-encoded spectrum with the initial spectrum curve, which can be acquired from the sinusoidal fitting method. In order to eliminate the phase ambiguity, a diaphragm-based Michelson interferometer is set up using a commercial 3 × 3 fiber coupler and two synchronized channels with 120° phase difference are employed for the interrogation. Experimental results indicate that the proposed method can provide stable demodulation results under random environmental fluctuations, while the commonly used edge filtering technique shows fluctuations of more than 10 dB under the same condition.

【 授权许可】

Unknown