System and method for spectral filtering of optical signals
US10989599B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 2019 |
| Grant date | Apr 27, 2021 |
| Priority date | — |
| Expiry date | Dec 5, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/06754
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for spectral filtering an input optical signal is described. The filtering system uses Brillouin gain inside an interferometer. The interferometer is biased to null signals that propagate without Brillouin gain, but due to asymmetric levels of gain in the interferometer arms the interference null is disturbed for signals of an optical frequency that experience Brillouin gain. The filter thereby preferentially passes signal frequencies that are inside the Brillouin gain bandwidth creating a high extinction ratio filter. The narrow bandwidth of the Brillouin gain effect can allow for spectrally narrow filters such as 30 MHz. The filter can be realized in a stable Sagnac loop configuration even if the pump and signal are combined prior to the Sagnac loop by using a power control device such as an attenuator placed asymmetrically inside the loop. The filter can achieve net gain and can be designed to have a tunable bandwidth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.