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We report an experimental observation of a blue shift in the n=1 heavy-hole exciton line of In0.53Ga0.47As/InP multiple quantum wells resulting from a picosecond photoexcitation in the transparent spectral region. The temporal response of this shift follows the excitation and it is attributed to the optical Stark effect. The shift was measured to be 0.19 meV for an incident light with a photon energy 20 meV below the exciton peak and with a 10-MW/cm2 intensity. [ABSTRACT FROM AUTHOR]

Near-band-gap optical nonlinearity in In0.53Ga0.47As/InP multiple quantum well (MQW) structures is studied by a combination of nonlinear absorption, pump-and-probe, and forward degenerate four-wave mixing experiments. Near complete saturation of the n=1 heavy-hole exciton is observed for the first time in In0.53Ga0.47As/InP MQW structures. Nonlinear susceptibility χ(3) is found to be 0.08 esu, which is about the same as that for GaAs/GaAlAs MQW structures. Saturation intensity is 200 W/cm2. [ABSTRACT FROM AUTHOR]

We have constructed all-optical logic étalons operating in the 1.55-μm wavelength region using InGaAs/InP multiple quantum well (MQW) structures. These étalons have low-energy requirements with several nanosecond recovery times, exhibit high on/off contrast (>20:1 if desired) with large on-state transmission (>40%), and have signal gain, thus making them possible to cascade. For example, we have performed gating using 6 pJ input energy with 5:1 contrast and gain about 2 at 100 MHz operating frequency. These étalons also show optical bistability. The nonlinear coefficients for the InGaAs/InP MQW’s deduced from experimental results are found to be on the same order as those for GaAs/GaAlAs MQW’s. [ABSTRACT FROM AUTHOR]

We report room-temperature lasing at 0.94–1.002 μm in high-finesse Fabry– Perot resonators with Inx Ga1-x As/GaAs multiple quantum well active layers (x=0.18–0.2). The quantum wells and AlAs/GaAs quarter-wave stack mirrors were epitaxially grown on GaAs substrates. Optically pumping with 0.875 μm, 10 ps pulses yielded a threshold of 15 pJ incident pulse energy. The equivalent threshold current density is about 26 μA/μm2 (2.6 kA/cm2 ), suggesting ultralow thresholds in micrometer-size devices. At the lasing wavelengths the GaAs substrates are essentially transparent allowing the possibility of integrating micro-optic lenslets on the substrate backsides for light collection. Nonlinear optical gating of 1.064 μm light was also achieved in these structures. [ABSTRACT FROM AUTHOR]

Intense single-peak photoluminescences of free-exciton origin were observed in InxGa1-x As/GaAs strained-layer quantum wells with x ranging from 0.09 to 0.20. Band lineups in these strained-layer heterostructures were determined by the dependence of luminescence energy on the well thickness. The heterojunction discontinuity in the heavy hole valence bands was found to be about 30% of the gap difference and independent of x. Exciton-phonon coupling was determined by temperature-dependent absorption measurements and the coupling strength was found to be similar to that of unstrained GaAs/AlxGa1-x As quantum wells. [ABSTRACT FROM AUTHOR]

Examines the epitaxial growth of strained-layer InGaAs/InGaAsP multiquantum well distributed feedback (DFB) laser. Location of the DFB laser in the multiquantum well; Exhibition of defect-free indium phosphide regrowth; Operation of the buried-hererostructures 6-quantum well DFB lasers.

We have achieved room-temperature pulsed and cw lasing at 980 nm in an optically pumped vertical cavity structure grown by molecular beam epitaxy containing only a single quantum well (SQW) of In0.2Ga0.8As. Limited gain due to the extremely short active material length of 80 Å implies that losses due to absorption, scattering, and mirror transmission are extremely low. Using 10 ps pump pulses at 860 or 880 nm, the estimated energy density absorbed in the spacer was ∼12 fJ/μm2 at threshold, indicating a carrier density approximately four times that required for transparency. Continuous wave pumping yielded an estimated threshold absorbed intensity of ∼7 μW/μm2. [ABSTRACT FROM AUTHOR]

Surface recombination of optically created electron-hole plasma in InGaAs/InP quantum well mesa structures formed by chemical beam epitaxy followed by anisotropic plasma etching is observed optically by a picosecond pump-probe method. The exponential carrier lifetime in 3.3-μm-diam structures is reduced from 31 ns as measured for large diameters to 5.5 ns. We ascribe this reduction to a surface recombination velocity of 1.2×104 cm/s. The surface recombination velocity is about two orders of magnitude smaller than those reported for bulk GaAs layers exposed to air. [ABSTRACT FROM AUTHOR]

Alterable temperature-dependent emission wavelength shifts were observed from (InP)[sub 2]/(GaP)[sub 2] short-period superlattices (SPSs) quantum wells grown with different interruption periods. Photoluminescence spectra showed that the peak energy of the SPS samples is inversely proportional to the interruption time conducted between the two consecutive binary growth sequences in the SPS regions. It is believed that a lateral composition modulation occurred during the interruption period which resulted in periodic In-rich and Ga-rich regions in the SPS quantum wells along the growth plane. With the lateral compositional variation, temperature variation can induce a multiaxial strain effect which can either amplify or reduce the temperature-dependent wavelength shift of the SPS quantum wells with different interruption periods. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]