Theory of a Fiber-Optic Double-Pass Mach-Zehnder Interferometer for use in a Brillouin Intensity Based Fiber-Optic Temperature Sensor

摘要

Many applications require the use of narrowband optical filters to separate two signals of closely spaced frequencies. The filter's performance can be determined by its throughput and rejection. For weak signals, the filter should provide both high throughput and high rejection of the adjacent signals. The development of a double-pass configured all-fiber Mach-Zehnder interferometric optical filter satisfies these requirements. The configuration is theoretically compared with a single-pass all-fiber Mach-Zehnder and a bulk Fabry-Perot interferometer and shown to have superior performance for certain applications.