Method and apparatus for spectrally designing all-fiber filters
US6130973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1998 |
| Grant date | Oct 10, 2000 |
| Priority date | — |
| Expiry date | Mar 26, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/02138
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and an apparatus to photoinduce a grating or other type of modulated refractive index change in a photosensitive optical medium such as optical fiber. The resulting grating has a variable and controllable intensity profile and average value of the index change. The modulated refractive index change is photoimprinted in the medium in a series of writing steps, each comprising exposing a segment of the medium to a writing beam for a predetermined exposure time. To change the modulation intensity from step to step, the angle of incidence of the writing beam is dithered for an appropriate fraction of the exposure time at each step. This allows to control the amount of incident light on the medium for each step. If the exposure time is the same for each writing step, the average value of the index change may be kept constant avoiding undesired structure in the grating frequency response.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.