Compensation of optical source phase noise in long-range OFDR by using an optical fiber delay loop

Abstract

We demonstrate a novel method to compensate the optical source phase noise in long-range OFDR by using an optical fiber delay loop (OFDL). In this method, a 10 km OFDL is incorporated in the reference interferometer of the reflectometry. A frequency shifter is used to count the circulation rounds of the light traveling in OFDL. The preliminary “proof-of-concept” experiment shows a successful compensation effect and an 11 cm spatial resolution over 20 km measurement range is realized by this method.