Integrated Optical Encoder

An integrated optical encoder consisting of a laser diode, monolithic photodiodes, and a fluorinated polyimide waveguide has been fabricated. It can determine which direction the grating scale is moving and can measure the relative displacement between the scale and the encoder, with a resolution on the order of 0.01/spl mu/m. By integrating the bulky components and using two beams emitted from two etched mirrors of the laser diode, this encoder is made as small as possible. The same design concept can be applied to other optical micro-sensors.