Fast polarization-dependent loss measurement based on continuous polarization modulation

A new technique for measuring the insertion loss and the polarization-dependent loss (PDL) of optical components is proposed. The technique is based on continuous polarization modulation of the stimulus optical field as opposed to sequential polarization state switching as in the traditional Jones matrix analysis or Mueller matrix methods. This new method relies on the simultaneous observation of multiple harmonics of the transmitted optical signal in the frequency domain. The physical theory of this method is presented along with PDL measurements performed on a polarization modulator, a polarizer, a PDL standard, and on an acetylene absorption cell exhibiting spectrally sharp insertion loss features.