Phase demodulation scheme for distributed interferometric sensor

Abstract

A new distributed interferometic optical fiber sensor (IOFS) for strain and vibrations measurement is proposed in the paper. It measures the first simultaneous information by using Mach-Zehnder Interferometer. The important points in regard to phase demodulation are explained. The system is all fiber and uses a 3×3 coupler for phase demodulation. Parameters such as strain sensitivity, transverse strain sensitivity, failure strain, and frequency response are discussed. The new scheme greatly reduces the complexity of practical fiber interferometer. An experimental setup has been implemented to demonstrate its expected merits. This type of IOFS has better sensitivity and resolution than others. At the time of writing, the system is only partially completed; therefore the content of this paper will focus on the principle of distributed optical fiber sensor. The results mainly are presented in laboratory.