Investigation of optical fiber based chemical sensors

• Main Author: Lim, Januarius Chih Kian
• Other Authors: School of Electrical and Electronic Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/61336
• Institution: Nanyang Technological University

Optic fiber exhibiting great advantages including high capacity, low signal degradation and immune to electromagnetic interference, has been extensively applied in the fields of optical communication and optical sensing. Especially, optical fiber based sensors to monitor the environmental changes have shown potential usefulness in our daily life covering medicine and chemical industries, food manufactory, bridge monitoring and so on. For the past 40 over years, it has been constantly under development and has produced many products and new technologies related to optical fiber sensors. In the project, we will concentrate on a scheme of optic fiber chemical sensor based on multimode interference and carbon nanotubes (CNTs) to enhance sensitivity. This report mainly involves three aspects: fiber based chemical sensors, refractive index sensing and temperature sensing. The basic sensing system consists of a light source, a sensor head constructed by optical fiber and an optical detector. When the fiber sensor experiences any external disturbance, the detector can detect the corresponding change in the optical signal. Based on this methodology, an experimental investigation is conducted by detecting the change of fiber sensor under test in order to trace back to the change of environmental such as refractive index and temperature. Modeling on the optical fiber sensor is included to predict the results which are done via MATlab. In addition, the optical deposition of CNTs on optical fiber to construct a fiber sensor is given in this report.