The Filter Wavelength Division Multiplexer is extensively used in EDFA, Raman amplifiers, WDM networks and fiber optics instrumentation. The FWDM series is based on environmentally stable Thin Film Filters technology. The device combines or separates light at different wavelengths in a wide wavelength range. They offer very low insertion loss, low polarization dependence, high isolation and excellent environmental stability. High power handling capability can be achieved through unique pigtail processing and high quality AR coating.