Semiconductor device including cascaded modulation-doped quantum well heterostructures
US5008717A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1989 |
| Grant date | Apr 16, 1991 |
| Priority date | — |
| Expiry date | Mar 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/0175
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Modulation-doped quantum well heterostructures are cascaded in a semiconductor device to achieve high speed operation while obtaining large index of refraction or absorption coefficient changes for modulating lightwave signals without significant increases in the operating potentials over prior quantum well structures. Each modulation-doped quantum well heterostructure exhibits substantially equal boundary conditions in an unbiased condition for efficient cascading or stacking. Each quantum well has associated with it a barrier layer to minimize leakage current. As a result, each quantum well has associated with it a separate charge reservoir. This aspect contributes to the speed of the cascaded structure. When incorporated within a waveguide structure, cascaded modulation-doped quantum well heterostructures can act as an external modulator, or as an intra-cavity wavelength tuning element, or as an intra-cavity modulator, or even as an optically-pumped laser.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.