Fabrication of active integrated optical micro-encoder

A novel integrated optical micro-encoder based on diffraction is presented, which can measure the relative distance traveled against a grating (scale) in the grating vector direction. A measurement resolution of less than 0.01 μm is possible. The encoder is extremely small, only 500-μm square, which is 1/100 the size of conventional encoders. Therefore, the encoder can be incorporated into a micro-machine and can be moved at high speed, since its inertia is extremely low. This encoder can be used even when the gap between the encoder and the grating is a few hundred micrometers