Abstract: An optoelectronic data transmission device has an active section with an active element that generates an optical gain if a forward bias is applied, and an absorption section. A waveguide incorporates the active section and the absorption section. Mirrors providing feedback for light are placed to frame the waveguide. The device can be operated in a pulsed regime emitting pulsed laser light. An additional modulator allows modulating its refractive index due to the electrooptic effect. A device providing for the modulation of the refractive index of the modulator. The refractive index of the additional modulator can be varied such that the repetition frequency of the output pulsed laser light is varied. The waveguide further incorporates the additional modulator.

Abstract: A method of fabricating a compositional semiconductor device comprising a antum well wire or quantum dot superlattice structure, in particular a device selected from the group comprising lasers, photodiodes, resonant tunneling transistors, resonant tunneling diodes, far infrared detectors, far infrared emitters, high electron mobility transistors, solar cells, optical modulators, optically bistable devices and bipolar transistors, by epitaxial growth of the superlattice structure on a semiconductor substrate, is characterised in that the epitaxial growth is effected on a {311}, {211}, {111} or {110} substrate, and that the devices preferably have length and width dimensions less than 500 .ANG. and especially less than 300 .ANG..