The F-PM850 Polarization Maintaining Fiber offers low attenuation and excellent birefringence for high performance applications. This Corning PANDA PM fiber has a 850 nm operating wavelength with beat lengths ranging from less than 1. 2x2 couplers are bidirectional and can be used to both split and combine signals (see the 2x2 Coupling Examples tab). Requests for custom fiber pigtails, different wavelengths and handling power of opera il: n. These polarization-maintaining fiber optic patch cables are terminated on both ends with high-quality, narrow key, ceramic FC/PC connectors, featuring high-quality polish with a typical return loss of 50 dB.