Patent ID: 7355792

Claim:
A coarse wavelength division multiplex (CWDM) optical filter for eliminating noise, comprising: a substrate; a first portion formed on the substrate and having at least two first stacking structures, each of the first stacking structures of the first portion having a Fabry-Perot cavity and a first coupling layer which are stacked over each other in turn from the substrate; a second portion superposed on the first portion, comprising at least two second stacking structures, each second stacking structure having an (HnLH) structure and a second coupling layer, wherein n is a positive integer greater than 1, L represents a low index layer with a thickness of Î» o /4, H represents a high index layer with a thickness of Î» o /4, and Î» o is the center wavelength of said noise; and a first matching layer sandwiched between the first and second portions.