Optical fibre sensor using frequency beating technique

• Main Authors: Resen, Deyhaa A., Hmood, Jassim K., Harun, Sulaiman Wadi
• Format: Article
• Published: Universiti Malaysia Perlis 2020
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/25267/; https://ijneam.unimap.edu.my/images/PDF/IJNEAM%20APR%202020/Vol_13_No_2_2020_3_241-248.pdf
• Institution: Universiti Malaya

In this paper, a new method to realize the optical fibre sensor using an optical heterodyne technique (OHT) is proposed and numerically demonstrated. In this method, the bandpass filter (BPF) was utilized as a reference element and fibre Bragg grating (FBG) served as a sensing element. The wideband light is equally split and launched to sensing and reference elements. The reflected light of sensing element coherently interferes with the output of BPF inside 3-dB coupler. A photodiode detects the interfered signal and the beat frequency can be determined to achieve a high-resolution. To examine the proposed method, the scheme for temperature sensing is investigated. The Fabry-Perot narrow-bandpass filter type (F7 glass) serve as BPF. The results reveal that a good and fast response to temperature change with the sensitivity of 1.152 GHz/oC can be obtained. © 2020, Universiti Malaysia Perlis. All rights reserved.