Narrow band filter and method of making same
US5612824A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1995 |
| Grant date | Mar 18, 1997 |
| Priority date | — |
| Expiry date | May 16, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/141
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical filter is provided having first and second graded index (GRIN) lenses preferably disposed in a coaxial relationship so that they have a common optical axis. Each of the GRIN lenses have an endface providing a port at predetermined location. The ports are disposed on opposite sides of the optical axis and each of the ports are substantially equidistant from the optical axis, so as to be oppositely offset from the optical axis by a same amount. The filter also includes an optical interference filter disposed between other endfaces of the first and second graded index lenses. By changing the location of the ports by a same small amount, the center wavelength of the filter changes by a small amount, thus in manufacture, the filter is tunable. After tuning the filter to a desired wavelength, the locations of the ports are fixed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.