Automatic in-fine fiber-optic polarization analyzers

In the paper two different configurations of automatic in-line fiber-optic polarization analyzers are presented. The principle of operation is based on birefringence modulation in the standard single-mode fiber and suitable detection of the harmonic amplitudes of the output electric signals. In the first one, called Fiber-Optic Polarization Analyzer, the polarimetric configuration with polarization modulation by squeezing a single-mode fiber is used. In the second, called Fiber-Optic Interferometric Polarization Analyzer, the modified Sagnac interferometer with standard piezoceramic ring modulator is applied. For both configurations briefly theoretical analysis of the polarization phenomenon is presented. As a main part of the paper the experimental results of the state as well as the degree of polarization parameters measurement are shown. In the experimental systems digital oscilloscope, function generator and PC with HPiB card and HP-VEE software for identification polarization parameters are used. In conclusion both systems are compared especially form measurement time and errors points of view.