Semiconductor laser device and driving method for the same as well as tracking servo system employing the same
US5533042A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1994 |
| Grant date | Jul 2, 1996 |
| Priority date | — |
| Expiry date | Oct 3, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S5/4031
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A semiconductor laser device which allows high speed correction of the position of a laser spot on an optical disk is disclosed. The semiconductor laser device comprises an active layer which oscillates a laser beam when electric current is supplied thereto, and a plurality of independent electrodes for varying the current density distribution in the active layer to vary the intensity distribution of the laser beam to be emitted from an emergent face of the semiconductor laser device. With the semiconductor laser device, by supplying electric currents individually from the plurality of independent electrodes to vary the current density distribution in the active layer, the beam spot position can be corrected within the frequency bandwidth of several tens MHz by direct modulation of the semiconductor laser device. Also a driving method for the semiconductor laser device and a tracking servo system in which the semiconductor laser device is incorporated are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.