Device and method for variable attenuation of an optical channel
US6434318B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 2000 |
| Grant date | Aug 13, 2002 |
| Priority date | — |
| Expiry date | Oct 4, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/0147
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A device for variable attenuation of an optical channel includes an elongated core surrounded by a cladding. Optical energy propagating along the longitudinal axis of the core is normally confined thereto by the difference in refractive indices between the core and cladding. The thermo-optic coefficients of the core and cladding are closely matched such that waveguide confinement is substantially invariant with respect to ambient temperature. The device further includes a thermal source arranged above the core. The thermal source is operable to generate a temperature gradient of controllable magnitude along a vertical axis extending through the core. The temperature gradient causes reduction of the local refractive index within the core relative to surrounding regions of the cladding such that a portion of the optical energy is deflected away from the thermal source and extracted from the core.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.