Long-period grating switches and devices using them
US5907647A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1997 |
| Grant date | May 25, 1999 |
| Priority date | — |
| Expiry date | Feb 18, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2201/30
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In accordance with the invention, an optical switch employs a long-period grating for switching light between alternative optical paths. In essence, the device comprises a variable intensity light source, a length of optical waveguide dimensioned for co-propagating light in two distinguishable modes, and a long-period grating in the waveguide for coupling between the two modes. The waveguide is nonlinear so that the effective refractive index is a function of intensity. As a consequence the coupling produced by the grating is a function of intensity. Thus different levels of light intensity can switch between the separate modes. Advantageously a mode separator is provided for directing light in the two modes onto respectively different optical output paths. A variety of two-mode switches and optical limiters are described, as well as an optical system using the switch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.