The 1550nm Polarization Maintaining Filter Coupler is a polarization maintaining coupler which splits the light from the input PM fiber into two output PM fibers. The PM Filter Coupler support the light wave of each polarization to work, without blocking any polarization. The rugged stainless steel package is designed for high optical performance and stability. This compact device offers low excess insertion loss, low back reflection, and high extinction ratio. Split ratios from 1 to 50% are available. The PM Filter Coupler can be used to split high power linearly polarized light into multiple paths without perturbing the line are state of polarization (SOP).It can also be used as a power tap to monitor signal power in a PM fiber system without disturbing the linear SOP of light propagating in the PM fiber. Applications include PM fiber interferometers, power sharing in polarization sensitive systems, and signal monitoring in PM fiber systems.