Enhancement of strain sensor sensitivity by combination of polarization maintaining fiber and single mode fiber in sagnac loop

• Main Author: Abdulrahman, Anas Malik
• Format: Thesis
• Language: English; English
• Published: 2019
• Subjects: TK7800-8360 Electronics
• Online Access: http://eprints.uthm.edu.my/463/1/24p%20ANAS%20MALIK%20ABDUL%20RAHMAN.pdf; http://eprints.uthm.edu.my/463/2/ANAS%20MALIK%20ABDULRAHMAN%20WATERMARK.pdf; http://eprints.uthm.edu.my/463/

Optical fiber-based sensing. techniques provide a unique set. of sensors which are small, easy to fabricate, lightweight, immune to electromagnetic interference (EMI), high sensitivity, large scale multiplexing, and in most cases inexpensive to manufacture. These advantages are the motivation behind continued researches and development in the field. The introduction, objectives, and the scope of work are presented in the first chapter. A review of the most popular of the optical and non-optical methods that is used to measure the strain is presented in chapter two. The methodology of work, analysis, and the results are presented in chapter three and chapter four, and the conclusion of this project in chapter five. This project investigates the fiber optic sensor. technologies that focus on the development. of fiber strain sensing element based on a combination of polarization maintaining fiber (PMF) and single mode fiber (SMF) in a Sagnac loop. Four cases are investigated in this work. The first, second, third and fourth cases involve 10 cm PMF, 20 cm PMF, 36 cm PMF + 4 cm SMF and 36 cm PMF + 14 cm SMF respectively as the strain element. Based on the experimental result, strain elements of 10 cm PMF, 20 cm PMF, 36 cm PMF + 4 cm SMF and 36 cm PMF + 14 cm SMF records sensitivities of 6.4 pm/μɛ, 14.7 pm/μɛ, 22.8 pm/μɛ and 25.3 pm/μɛ correspondingly for a range 0-1000 μɛ at 25 Cº temperature. It shows that the strain element of 36 cm PMF + 14 cm SMF possesses the highest sensitivity. In addition to the experimental results, simulation work is also done for comparison. The Sagnac loop model developed with Jones matrices agrees well with the experimental results.