Controlled Fabrication System of Fabry-Perot Optical Fiber Sensors

Abstract

The use of optical fiber sensors is increasing widely in industry, civil, medicine, defense and research. Among different categories of these sensors is the Extrinsic Fabry-Perot interferometer (EFPI) sensor which is inherently simple and requires only modest amount of interface electronics. These advantages make it suitable for many practical applications. Investigating a cost-effective, reliable and repeatable method for optical fiber sensor fabrication is challenging work. In this thesis, a system for controlled fabrication of Fabry-Perot optical fiber sensors is developed and presented as the first attempt for the long-term goal of automated EFPI sensor fabrication. The sensor fabrication control system presented here implements a real-time control of a carbon dioxide (CO₂) laser as sensor bonding power, an optical fiber white light interferometric subsystem for real-time monitoring and measurement of the air gap separation in the Fabry-Perot sensor probe, and real-time control of a piezoelectric (PZT) motion subsystem for sensor alignment. The design of optoelectronic hardware and computer software is included. A large number of sensors are fabricated using this system and are tested under high temperature and high pressure. This system as a prototype system shows the potential in automated sensor fabrication.