Cascaded optical modulation system with high linearity
US5278923A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1992 |
| Grant date | Jan 11, 1994 |
| Priority date | — |
| Expiry date | Sep 2, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/19
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical modulation system having cascade-coupled electro-optic modulator stages in either dual tandem or split tandem configurations. An electrical splitter derives multiple electrical drives for the multiple stages from a single modulating input signal. The multiple drive signals are linearly related in magnitude and preferably induce simultaneous antiphase (180.degree. out-of-phase) optical modulation in the tandem stages. While a double Mach-Zehnder cascade configuration could be used, at least one modulator stage might instead be a balanced-bridge interfometer-type modulator having at least one directional coupler. At least one directional coupler in such a configuration may be a .DELTA..beta. coupler. Application of bias voltages to the interferometer sections and to coupler sections by means of a parametric feedback loop is done in order to simultaneously enhance the linear modulation coefficient, minimize odd order distortions and null the even order distortions that are associated with biased .DELTA..beta. couplers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.