Laser controlled by a multiple-layer heterostructure

Abstract

The invention is a controlled laser having an optical resonator, a laser gain medium placed inside the optical resonator, the laser gain medium being capable of emitting light and of lasing with the light, a multiple layer heterostructure placed inside the optical resonator, and means for varying an optical absorption of the multiple layer heterostructure for the light in order to control an optical gain of the optical resonator, and thereby control lasing of the laser gain medium. Passive mode locking is achieved by the light emitted by the gain medium controlling the optical absorption of the multiple layer heterostructure. Active mode locking and modulation are achieved by controlling the optical absorption of the multiple layer heterostructure by applying an electric field to the multiple layer heterostructure. Control of laser gain by an external light source is achieved by controlling the optical absorption of the multiple layer heterostructure by illuminating it with light from the external light source. An embodiment of the multiple layer heterostructure fabricated as a GaAs-AlGaAs multiple quantum well with a Type I superlattice band structure is a passive mode locker for a semiconductor diode laser.