There is presented an optical frequency domain reflectometry (OFDR) system (100) comprising a first coupling point (15) arranged for splitting radiation into two parts, so that radiation may be emitted into a reference path (16) and a measurement path (17). The system further comprises an optical detection unit (30) capable of obtaining a signal from the combined optical radiation from the reference path and the measurement path via a second coupling point (25). The measurement path (17) comprises a polarization dependent optical path length shifter (PDOPS, PDFS, 10), which may create a first polarization (PI) and a second polarization (P2) for the radiation in the measurement path, where the optical path length is different for the first and second polarizations in the measurement path. This may be advantageous for obtaining an improved optical frequency domain reflectometry (OFDR) system where e.g. the two measurements for input polarizations may be performed in the same scan of a radiation source.