Multilayer thin film bandpass filter
US6018421A · kind A · utility
Inventor
Key dates
| Filing date | Sep 12, 1997 |
| Grant date | Jan 25, 2000 |
| Priority date | — |
| Expiry date | Sep 12, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A novel design for producing bandpass filters with essentially square shapes with little or no ripple in the passband zone. Filters are of the all-dielectric type consist of multiple cavities of bandpasses. Quarter wave thick layers of low index material separate all of the cavities from each other. Multiple half-waves may be added to the outer cavity quarter-wave stacks in particular. This invention provides the addition of half wave to some of the inner cavity stacks to remove ripple that would otherwise be present. Together, these additional half wave layers added to the outer and inner cavities sharpen the transition from low transmission to high transmission without unduly adding ripple to the high transmission zone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.