Widely tunable gain-switched operation of external cavity grating-coupled surface emitting laser

Widely tunable gain switching of a grating-coupled surface-emitting laser (GCSEL) has been demonstrated in a simple external cavity configuration for the first time. Pulse duration in range of 40-100ps and wavelength tuning over 100nm have been achieved. High power, tail-free optical pulses have been observed at 980nm

The two-photon absorption semiconductor waveguide autocorrelator

In this paper, we report a novel semiconductor waveguide autocorrelator that employs two-photon absorption (TPA), rather than the more commonly used second-harmonic generation, as its nonlinear mechanism. An introduction to TPA is given, and the reasons for its use in the autocorrelator are explained with reference to nonlinear absorption experiments. We then describe the fabrication of the p-i-n GaAs/AlGaAs waveguide. The initial experiments carried out with a single beam in the waveguide are described and fitted to theory. Autocorrelation traces for both a CW modelocked Nd/sup 3+/:YAG laser at 1.06 /spl mu/m and a Q-switched InGaAsP/InP laser at 1.3 /spl mu/m are presented and their pulsewidths obtained by means of a theoretical model. The sensitivity and resolution of the TPA waveguide autocorrelator are then discussed, as is a proposal for a multiple-contact TPA waveguide autocorrelator, designed so that the two pulse trains are counter-propagating. This would result in an autocorrelator from which the laser pulsewidth could be obtained in a single measurement, with no moving parts, and which could be integrated with a semiconductor laser

Decomposition and stability of group-III nitride ternary cubic spontaneously ordered alloys

Spinodal decomposition temperatures are calculated for cubic ternary InGaN, GaAlN, InAlN, and GaAsN alloys with an arbitrary degree of CuPt-type spontaneous ordering. It is shown that ordered alloys (superstructures) are potentially more stable with respect to decomposition than random alloys

Optoelectronic microwave-range frequency mixing in semiconductor lasers

Optoelectronic mixing of very high-frequency amplitude-modulated signals using a semiconductor laser simultaneously as a local oscillator and a mixer is proposed, Three possible constructions of a monolithically integrated up-or down-converter are considered theoretically: a four-terminal semiconductor laser with dual pumping current/modal gain control, and both a passively mode-locked and a passively Q-switched semiconductor laser monolithically integrated with an electroabsorption pumping current modulator. Experimental verification of the feasibility of the laser-mixer concept is presented