Polarization dependent return loss measurement

The present invention relates to an apparatus and to a method of optical characterization of a DUT by measurement of its optical return loss, comprising the steps of: providing an incident polarized optical signal to the DUT, detecting a reflected power of a reflected optical signal reflected by the DUT as a function of the polarization of the incident optical signal, and evaluating the optical return loss of the DUT as a function of the polarization of the incident optical signal on the basis of the detected reflected power.