Integrated optical 90 degrees-hybrid on LiNbO3 for phase diversity receivers

An integrated optic eight-port 90 degrees -hybrid has been realized on LiNbO3. The phase pattern was tuned electro-optically. The packaged unit showed the desired phase relations of 0 degrees , 90 degrees , 180 degrees and 270 degrees between the respective output ports with excellent longterm stability. The phase fluctuations are less than +or-5 degrees and the temperature induced phase drift is 15 degrees / degrees C.