Fiber optic interferometer sensor for responsive hydrogel based heavy metal cation detection

• Main Author: Koh, Tee Wee
• Other Authors: Julian
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/60243
• Institution: Nanyang Technological University

This project objective aimed to fuse a Mach-Zehnder type interferometer and using the hydrogel volume phase transition theory to measure the refractive index dependence due to the heavy metal concentration. The refractive index sensor was made by splicing a three centimeter photonic crystal fiber (PCF) and placing it in between two single mode fibers. To allow the coupling of various modes, the air holes of PCF must be fully collapsed at the spliced region. The hydrogel will be coated onto the PCF interferometer via dipping into it. The copolymerizing of both polyacrylic acid with polyvinyl alcohol and cross-linkers incorporated epoxy groups as molecular recognition agents for 5-amino-8-hydroxyquinoline. The heavy metal cation will induced hydrogel to swell and shrink according to the RI changes, and can be transduced to an optical signal using an interferometric optical fiber sensor.