Abstract: Optical semiconductor device with resonant cavity tunable in wavelength, application to modulation of light intensity. This device comprises a resonant cavity (2) delimited by two mirrors (4, 6) and at least one super-lattice (14) that is placed in the cavity and is formed from piezoelectric semiconducting layers, and means (20) of injecting charge carriers into the super-lattice. The optical properties of this super-lattice can thus be modified and the wavelength of cavity resonance modes can be offset. The invention is particularly applicable to optical telecommunications.

Abstract: Semiconductor laser with a tunable gain spectrum. Said laser comprises an active zone having at least one active quantum well (AQW), which emits a laser radiation during the introduction of carriers into the active zone and at least one collection quantum well (CQW1, CQW2) on either side of the active well, for collecting and confining part of the carriers introduced. Means for distributing carriers in the collection wells are provided for creating a space charge field for modifying, during the emission of radiation and by an electrooptical effect, the gain spectrum of said active well. Application to optical telecommunications.