Active modulation of quantum well lasers by energy shifts in gain spectra with applied electric field

摘要

Modulation of a semiconductor laser device is achieved at microwave frequencies by the application of transverse fields which produce energy shifts in the gain spectra of the laser device. The laser device is a PN diode which has a body portion constructed from a nonconductive material, with P and N type implants on opposite sides. The P and N implants define a transition region, or layer, on the order of 1 micron in width, in which is formed a quantum well having a thickness on the order of 50 to 100 Angstroms. Application of a bias voltage across the PN junction provides lasing of the device. An electrode on the surface of the transition layer allows application of a transverse electric field to the PN junction. This transverse field quenches the lasing of the device, to provide modulation of the laser. Quenching is produced by means of energy shifts in the gain spectra of the laser device, and since current flow through the PN junction is inhibited by the nonconductive material and thus flows primarily in the quantum wells, modulation of the current is possible at microwave frequencies at relatively low power levels.