Max-planck-gesellschaft Zur F&#xf6;rderung Der Wissenschaften E. V.

Ernst O Gobel

Jurgen Kuhl

Klaus Ploog

Helmut Jung

Gustav Veith

Reiner Hoger

A semiconductor laser device comprises a plurality of layers of semicondung materials, first contact means providing electrical contact to a basal layer of the device and second contact means providing electrical contact to an upper layer of the device, with at least one layer disposed between the basal layer and the upper layer being selected to be sufficiently thin that size quantization occurs, i.e. that a semiconductor device with a quantum well structure is created. The second contact means comprises a first strip-like contact overlying a first lasing region of the device and a second strip-like contact overlying a second lasing region of the device. The light losses associated with photons generated by laser action in the first region are intentionally made different from the light losses associated with photons generated by laser action in the second region which permits laser action at two distinct wavelengths in a monolithic device.

Integrated quantum well lasers having uniform thickness lasing regions

A method and an apparatus are described by producing optical radiation pulses with a duration of the order of picoseconds (10.sup.-12 s) and less using external mode locking of the longitudinal laser modes of a semiconductor laser element operating in an external resonator. In the method of the invention the gain modulation, needed for synchronous mode locking, of the active semiconductor laser element is effected by modulation of the electrical pumping current by way of a high-speed optoelectronic switch, that for its part is controlled by a mode locked master laser. The present method combines the advantages of synchronous optical pumping, as used in commercial mode locked dye laser systems, with the simple type of electrical pumping of commercially available semiconductor laser diodes, more especially double heterostructure laser diodes. It respresents a simple and economic alternative to synchronously pumped dye laser systems and considerably extends the spectral range within which radiation pulse may be produced with a duration of the order of picoseconds.

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Leinfelden-Echterdingen, Germany

Ernst O Gobel