Semiconductor modulator with a .pi. shift
US5694504A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 8, 1996 |
| Grant date | Dec 2, 1997 |
| Priority date | — |
| Expiry date | Mar 8, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/255
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A MQW semiconductor Mach Zehnder phase modulator is formed by two Y-junctions (12, 32), each having a single waveguide (14) optically coupled with two branch waveguides (18, 20). The branch waveguides of the two Y-juntions are optically coupled in Mach-Zehnder configuration that, under zero bias conditions, has one interferometric arm longer than the other to provide a .pi. phase shift. The additional length is preferably accommodated in the branches of the Y-junctions. The phase shift, in combination with voltage dependent absorption properties and non-linear phase variations of the MQW guided regions in the Mach-Zehnder modulator results in a negative chirp and high extinction ratio for an equal, push-pull device configuration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.