Patent ID: 6011652
Filing Date: 2000-01-04
Classification: G02B

Abstract:
A bandpass filter having at least a primary passband region and a secondary passband region within transmission zones of the filter and outside the reflection zones of the filter, the filter comprising at least two outer cavities and at least one inner cavity disposed therebetween, each cavity having a spacer region of at least a high or low index material disposed between two reflector stacks, the thickness of the spacer regions in the cavities are of a thickness of a halfwave or a multiple-half-wave at the primary passband the reflector stacks of any of the cavities including quarter wave layers, said quater wave layers being a quarter wave in thickness at the primary passband, the reflector stacks of a plurality of cavities, including at least one inner cavity, including one or more non-quarter wave layers at the primary passband, said one or more non-quarter wave layers having a thickness excluding a quarter wave or an integer multiple of a quarter wave at the primary passband for enhancing transmission in the secondary passband.