TEMPERATURE INSENSITIVE FIBER BASED MACH-ZEHNDER INTERFEROMETER FILTER DEVICES

摘要

A Mach-Zehnder interferometer having two optical couplers intercommunicated by two optical fibers one or each of which is temperature insensitive. In use, temperature induced changes in the geometrical length and refractive index of the or each of the two temperature insensitive fibers offset each other so that the optical path length of the fiber is unaffected by temperature change. Where two temperature insensitive fibers are included these may be of the same or of different lengths. The interferometer may be used in a Dense Wavelength Division Multiplex system.