OPTICAL HETERODYNE RECEIVER WITH INTEGRATED OPTICAL POLARIZATION CONTROL

摘要

In an optical heterodyne receiver, received light is heterodyned with the light generated by a local laser. A precondition of the heterodyning is the identical polarisation of the two light waves. Since the polarisation of the light transmitted via optical waveguides can change, automatic control of polarisation is necessary, and this has previously required at least three birefringent elements. In order to reduce the complication, use is made according to the invention of an integrated optical birefringent element in which there are arranged on an electro-optical substrate parallel to an optical waveguide arranged in the substrate three electrodes on the substrate surface to which specific voltages are applied. In order to correct manufacturing tolerances, it is possible to mount on the electro-optical substrate a correction element which has the same structure as the first birefringent element.