Abstract: The present invention relates to a separate confinement heterostructure laser, and in particular to a stripe geometry, ridge waveguide geometry, having an active layer positioned between a pair of n-type and p-type emitter layers which inject charge carriers under the ridge guide into the active layer. A pair of ohmic contacts are used to inject one type of charge carrier into at least one emitter layer outside the ridge area. When a signal is applied to the pumping contacts (p- and n-type) in forward bias and an intermittent electric field is applied to the ohmic side contacts, the flow of current injected by the side contacts controls the densities of carriers injected by the pumping contacts, thereby controlling spatially and temporally the optical gain and optical confinement factor.

Abstract: The output electromagnetic power of optoelectric heterojunction semiconductor devices having an active semiconductor layer with a mobile charge carrier plasma is controlled by applying a microwave electric field inside the active layer by means of at least two semiconductor contacts to the active layer that are conducting to at least one type of mobile charge carrier and blocking to another type of charge carrier. An electrical signal is applied inside the active layer to transform the distribution of energies and equivalent temperature of the charge carriers of the mobile charge carriers in order to control light emission and absorption in the active layer. A modulator is disclosed with two such semiconductor contacts on the active layer in which charge carriers are optically generated. A monolithically integrated, cavity-coupled laser and modulator is disclosed in which the laser and modulator are fabricated on a common substrate and the laser is a distributed feedback laser (DFB).

Abstract: We have discovered that coherent variation of at least two laser parameters can result in improved device performance, e.g., in pure amplitude or frequency modulation at frequencies substantially above 1 GHz, or in previously unattainable modulation frequencies. Among the relevant laser parameters are pumping rate, optical gain coefficient, photon lifetime, confinement factor, effective carrier temperature, output frequency and spontaneous emission factor. Exemplarily, the pumping rate and the optical gain are coherently varied such that the output radiation is free of chirp, or the output frequency and the effective carrier temperature are coherently varied such that the output radiation has constant amplitude.

Abstract: An article that comprises novel means for modulating the transparency of a semiconductor body in accordance with a modulating signal is disclosed. The body comprises one or more quantum wells (QWs), and the modulation mechanism comprises changing the free carrier distribution function in the QWs. An important feature of the inventive article is the use of (relatively long wavelength) inter-subband radiation (ISBR) to change the transparency of the body for (relatively short wavelength) inter-band radiation (IBR). In preferred embodiments the modulating signal is an electric field applied across the QWs, such that ISBR absorption can be tuned by means of the Stark effect. One embodiment of the invention makes it possible to rapidly modulate IBR, and another embodiment can form narrow (typically less than 10 ps) IBR pulses.

Abstract: The output electromagnetic power of optoelectric heterojunction semiconductor devices having an active semiconductor layer with a mobile charge-carrier plasma is controlled by applying a microwave electric field inside the active layer by means of at least two semiconductor contacts to the active layer that are conducting to at least one type of mobile charge carrier and blocking to another type of charge carrier. An electrical signal is applied inside the active layer to transform the distribution of energies and equivalent temperature of the charge carriers of the mobile charge-carrier plasma in order to control light emission and absorption in the active layer. A heterojunction semiconductor laser is disclosed with two sets of electrical contacts: one to apply pumping currents and the other to control the electric field.