Release Time:2019-03-11  Hits:

Indexed by: Journal Article

Date of Publication: 2015-09-01

Journal: PHOTONIC SENSORS

Included Journals: Scopus、EI、SCIE

Volume: 5

Issue: 3

Page Number: 217-223

ISSN: 1674-9251

Key Words: Distributed temperature sensor; incoherent optical frequency domain reflectometry; radio-frequency lock-in amplifier; simultaneous detection

Abstract: Weak signal detection for single-mode fiber-optic distributed temperature sensor (DTS) is a key technology to achieve better performance. A hybrid technique combining the incoherent optical frequency domain reflectometry (IOFDR) and the three-channel simultaneous radio-frequency (RF) lock-in amplifier (LIA) is presented to improve the signal-to-noise ratio (SNR) of the measured spontaneous Raman backscattered light. The field programmable gate array (FPGA) based RF-LIA is designed with a novel and simple structure. The measurement frequency range is achieved from 1 kHz to 100 MHz. Experimental results show that the backscattered light signal of picowatt level can be detected with high SNR. With a 2.5 km single-mode fiber, a 1064 nm laser source, and the measurement time of 500 s, this sensing system can reach a spatial resolution of 0.93 m and a temperature resolution of about 0.2 degrees C.