TEMPERATURE INSENSITIVE MACH-ZEHNDER INTERFEROMETER

摘要

A Mach-Zehnder interferometer comprising two optical couplers intercommunicated by two optical fibers. One of the optical fibers has a predeterminded portion o f its length surrounded by a coat. The material of the coat has a coeffiecient of thermal expansion which, in combination with the dimensions of the coat, influences the characteristics of the fiber to render it temperature insensitive. In this temperature insensitive fiber, temperature induced changes in the geometrical length and refracture index of the fiber offset each other whereby the optical path length of the fiber is unaffected by change i n temperature. Also included is an optical fiber of specific length and having such a coat over a predetermined portion of its length to render the fiber temperature insensitive.