Fabrication of advanced integrated optical micro-encoder chip

An advanced integrated optical microencoder whose traveling direction relative to a grating scale can also be detected and whose traveling displacement can be measured with a resolution on the order of 0.01 microns was developed. Combination of laser diode, polyimide waveguides, and optical films such as a 90/spl deg/ phase-shifting film and gradient-refractive-index-lens film resulted in a microencoder small enough to be placed with a volume of a few cubic millimeters.