Optical fiber attenuator with attenuating dopant limited to a central or peripheral area of the fiber core
US6748151B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 2001 |
| Grant date | Jun 8, 2004 |
| Priority date | — |
| Expiry date | Jun 21, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/266
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical attenuator which provides almost the same degree of attenuation even when the difference in wavelength of two different kinds of input optical signals is small. Another optical attenuator is provided with a dopant concentration in a technically realizable range which increases the difference in optical attenuation of two different kinds of input optical signals. Almost the same degree of attenuation may be obtained even when the difference between wavelengths is small by canceling the wavelength dependency of attenuation of the dopant by raising the refractive index of an axially central portion of the core as compared to that of the peripheral portion of the core and by taking into account the type and area of the dopant and the ratio of the difference &Dgr;2 between the refractive indexes of the cladding and the axial portion of the core and the difference &Dgr;1 between the refractive index of the cladding and the refractive index of the peripheral portion, i.e., &Dgr;1/&Dgr;2. On the other hand, the difference of attenuation is increased while suppressing the concentration of dopant to the realizable range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.