BULK OPTIC ECHELON MULTIPLEXER

BULK OPTIC ECHELON MULTI/DEMULTIPLEXER Bulk optic echelon gratings suitable for use in multi/demultiplexing optical signals carried on sets of optical fibers. The gratings can be either reflective or transmissive and may be either curved with self-focus-ing properties or planar requiring the use of auxiliary collimating optics. All versions have the property of being simultaneously blazed at at least two different wavelengths whose ratio is in the range between 0.8 and 0.9. This property of the gratings enables their operation over preferred multiple wavelength bands using a limited set of fibers which are fixed in place. Preferred wavelengths at which the gratings are simultaneously blazed include 1.3 and 1.55 micrometers. Devices incorporating the gratings can be used singly or in groups in inverted tree arrangements for tandem or hierarchical multiplexing purposes.