The Polarization Changing Speed of the LightDepolarized by a Simple Depolarizer

A measure of polarization changing speed of the light depolarized by a simple depolarizer is proposed. The polarization changing speed can be quantified by using the variance of the average of polarization state. In addition, the measure is theoretically formulated as a function of the linewidth of a light source. For this goal, the polarization state parameter is defined, and its autocorrelation is derived mathematically. Because the proposed measure is based on the statistics of averaged polarization, it also gives us the statistical information of the average of the physical quantity directly related to the polarization. For verification of the physical importance, an experiment is performed. The experimental result shows good agreement with theory. The proposed measure is proven to be suitable for quantifying randomly varying polarization changing speed.