The F-PM1550 Polarization Maintaining Fiber offers low attenuation and excellent birefringence for high performance applications. This Corning PANDA PM fiber has a 1550 nm operating wavelength with beat lengths ranging from less than 1. Optimized for use at 1550 nm, these fibers are used in all PM applications for data and telecom. Coherent has applied its unique manufacturing facility and capabilities to this product area and has. Description 400 to 1550 nm; Mode Field Dia. 80, 125 µm Field-proven as the industry standard, Corning's PANDA PM series of polarization. TruePhase® Bend-Insensitive Polarization-Maintaining (BI PMF) Optical Fiber for use in small bend radius applications that demand superior bending performance.