Measurement of the polarization and phase of an optical signal by coherent detection.

We present a four-dimensional polarization and phase calculus that is similar to the Jones calculus but emphasizes the relation between polarization and phase. We use this calculus to prove that acombined polarization- and phase-diversity scheme requires at least four photodetectors. We also use this calculus to describe the operation principle of a novel balanced polarization and phase hybrid.this hybrid can be used, e.g., for the complete characterization of a polarization controller.