Design Of A Strain Measurement System Based On Michelson Fiber Optical Interferer Sensor

In this paper, an all-fiber interferential sensing system which has simple configuration and high accuracy is designed for the reason of topic research and the demand of actual item. This measurement system includes fiber optical interferer sensor, counter module, controller circuit and PC communication module. Based on the 2π/3 phase difference when interference beam pass through the coupler, the signal is magnified, shaped and filtered by the demodulator comprising 3×3 directional coupler and demodulation circuit, and can be demodulated by the demodulation circuit directly. Counter module is based on the technology of CPLD, which is able to achieve the specified high accuracy of the measurement system. The data collections, communications and counter module clearing are realized by controller circuit. The core of the controller circuit is AT89S52 single chip.This paper contains two main parts. The first part introduced the theory of Michelson fiber optical sensor, and analyzed the conditions of the occurrence of interference phenomenon and the composing of Michelson Fiber Optical Interferer Sensor. Then it focuses on the operational principle and main components of fiber optical sensor based on 3×3 directional coupler. The second part is illustrated from the development of hardware and software. It emphasized the design process of the measurement system and have detailed analysis to the components of the measurement system. It also gave the architecture of Michelson Fiber Optical Interferer measurement system.