Polarization-independent optical circulator: an experiment.

Many kinds of optical devices are being researched in various countries for application in optical fiber communication. Some devices have polarization-dependent characteristics that cause a decrease in the coupling efficiency of the optical fibers. This paper proposes a configuration method using an optical circulator whose characteristics are independent of the polarization condition of the incoming light. Using components such as YIG crystals, polarization prisms, compensating plates, and magnet rings, it was experimentally confirmed that the insertion loss and the isolation were 3.7 dB and 10-20 dB, respectively, at lambda = 1.27 microm and that the polarization dependence was greatly decreased.