Distributed feedback laser for frequency modulated communication systems
US4908833A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jan 27, 1989 |
| Grant date | Mar 13, 1990 |
| Priority date | — |
| Expiry date | Jan 27, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/124
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
To overcome the deleterious effects of the nonuniform frequency modulation response in semiconductor lasers due to current injection in direct frequency modulation applications, it has been determined that the linewidth enhancement factor .alpha. be made as large as possible. In one embodiment, distributed feedback lasers well suited for frequency modulation lightwave communication systems are designed to have an integrated feedback element such as a corrugation grating whose effective pitch is selected to cause the Bragg wavelength and, therefore, the laser operating wavelength to be longer than the wavelength at substantially the maximum gain or gain peak in the semiconductor structure without the grating. That is, the wavelength of the grating is effectively detuned toward the longer wavelength and lower energy side of the peak of the gain profile. Such detuning increases the linewidth enhancement factor in such a way that the nonuniform frequency modulation response and its effects are minimized and, in some cases, substantially eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.