All fiber gain flattening optical filter
US6362916B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 1999 |
| Grant date | Mar 26, 2002 |
| Priority date | — |
| Expiry date | Feb 9, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/266
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An all fiber optical filter is formed by stretching an optical fiber. The all fiber filter includes a core, an inner cladding and an outer cladding. A core index of refraction is greater than an outer cladding index of refraction. The outer cladding index of refraction is greater than an inner cladding index of refraction. The all fiber optical filter attenuates a portion of an optical signal by transferring optical energy from the core to the outer cladding by evanescent coupling. The all fiber optical filter has a compact structure, which prevents bending and provides stable temperature performance. The all fiber optical filter is preferably used in Wavelength Division Multiplexing (WDM) systems for gain flattening of gain responses from Erbium Doped Fiber Amplifiers (EDFAs). Alternatively, the all fiber optical filter is used in other applications where optical filtering or attenuation is needed. The all fiber optical filter is manufactured by holding a length of an appropriate optical fiber between two clamps, heating the optical fiber, and stretching the optical fiber until a predetermined characteristic of the all fiber optical filter is achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.