FIBER RECIRCULATING DELAY-LINE TUNABLE DEPOLARIZER

A new type of all-single-mode fiber depolarizer, based upon a 2 x 2 co upler and a recirculating delay line and useable with a coherent light source, is proposed and demonstrated. The reduction in the degree of polarization is examined theoretically and experimentally. Design crit eria and principles are discussed. With a narrow-band laser source, th e degree of polarization was tuned between 99.8% and 1.15%. Experiment s illustrate how this depolarizer can eliminate the effects of induced polarization fluctuation in a polarization-sensitive fiber-optic syst em. The experimental results support the theoretical model. (C) 1998 O ptical Society of America.