Apparatus and method for controlling an extinction ratio of a laser diode over temperature
US5502298A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 22, 1994 |
| Grant date | Mar 26, 1996 |
| Priority date | — |
| Expiry date | Aug 22, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/06835
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A circuit for controlling an extinction ratio of a laser whose temperature can change over time includes first and second feedback loops which monitor a LOW output power of the laser during a first frame training pulse and a HIGH laser output power during a second frame training pulse. The LOW power output is compared to a preset dynamic LOW power reference, and a LOW bias current applied to the laser is incrementally increased or decreased so as to keep this LOW power output toggling about this LOW reference. Similarly, the HIGH power output is compared to a HIGH power reference, and a modulation current for the laser is incrementally increased or decreased to keep the HIGH laser output power toggling about this HIGH reference. Preferably, the training pulse is sent once per frame thus enabling both the LOW and HIGH laser output powers to be kept constant regardless of whatever dynamic variables may change over time thus keeping the laser extinction ratio constant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.