Polarization Effects in Optical Free Space Communications

Polarization control in free space laser communications systems plays a critical role in systems modeling, design and configuration. The key issues of transmit/receive isolation and transmitted beam polarization form the basis of the discussion. Optical systems utilizing polarization effects differ from conventional optical systems in both design and analytical treatment. Starting with a review of polarization definitions and concepts, the discussion proceeds with the outline of a polarization based laser communications satellite design. The practical performance limitations due to polarization effects are discussed. The Mueller Calculus matrix algebra method is presented as a convenient and powerful analysis technique for analyzing polarization effects. Computer simulated polarization performance for the two satellite configuration of a laser cross link communications system illustrates this point.