Abstract

DWDM devices made by all dielectric thin film interference filters are totally passive, high thermal stability, and low polarization-dependent losses,^1,2 which have been becoming the most popular and important key components used in current optical-fiber communication systems. These interference filters are constructed based on Fabry-Perot (FP) interferometer or etalon,³ which consists of two identical parallel reflectors separated by a spacer with an optical thickness of an integral number of half-waves. The reflector is a multilayer stack with the alternating Ta₂O₅ and SiO₂ films used as high and low refractive-index layers, respectively, and the thickness of each layer is quarter-wave. For 100 or 200 GHz DWDM filters, a 3- or 4-cavities narrow bandpass filter was constructed with the total number of layers and thickness are above 100 layers and 20 µm, respectively. ⁴

© 2001 Optical Society of America