Abstract-We analyze the high-temperature continuous-wave performance of 1.3-m AlGaInAs/InP laser diodes grown by digital alloy molecular-beam epitaxy. Commercial laser software is utilized that self-consistently combines quantum-well bandstructure and gain calculations with two-dimensional simulations of carrier transport, wave guiding, and heat flow. Excellent agreement between simulation and measurements is obtained by careful adjustment of material parameters in the model. Joule heating is shown to be the main heat source; quantum-well recombination heat is almost compensated for by Thomson cooling. Auger recombination is the main carrier loss mechanism at lower injection current. Vertical electron escape into the -doped InP cladding dominates at higher current and causes the thermal power roll-off. Self-heating and optical gain reduction are the triggering mechanisms behind the leakage escalation. Laser design variation is shown to allow for a significant increase in the maximum output power at high temperatures.Index Terms-Laser thermal factors, optoelectronic devices, quantum-well devices, semiconductor device modeling, semiconductor laser.

The characteristics of period-one oscillations in semiconductor lasers subject to optical injection are experimentally and theoretically investigated. Attention is mainly paid to the relative dependence of the frequency and the magnitude between the principal oscillation and the first sideband in period-one oscillations as a function of the detuning frequency and the injection strength of the injection signal. The frequency separation between the two signals is found to decrease as the injection strength and the detuning frequency reduce. The magnitude of the principal oscillation decreases with the decreasing injection strength and the increasing detuning frequency, while that of the first sideband grows at the same time. At some operating conditions, the magnitude of the first sideband dominates that of the original principal oscillation, resulting in a frequency shift of the principal oscillation from the injection frequency to the first sideband. Similar studies are also done for the stable injection locking to explore the transition of the frequency and the magnitude characteristics across the Hopf bifurcation line. The effects of different bias current levels of the injected laser on the frequency and the magnitude characteristics of period-one oscillations are also investigated.

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We report results of a scanning spreading resistance microscopy ͑SSRM͒ and scanning capacitance microscopy ͑SCM͒ study of the distribution of charge carriers inside multi-quantum-well ͑MQW͒ buried heterostructure ͑BH͒ lasers. We demonstrate that individual quantum-well-barrier layers can be resolved using high-resolution SSRM. Calibrated SSRM and SCM measurements were performed on the MQW BH laser structure, by utilizing known InP dopant staircase samples to calibrate the instrumentation. Doping concentrations derived from SSRM and SCM measurements were compared with the nominal values of both p-and n-doped regions in the MQW BH lasers. For n-type materials, the accuracy was bias dependent with SSRM, while for SCM, excellent quantitative agreement between measured and nominal dopant values was obtained. The SSRM was able to measure the dopant concentration in the p-type materials with ϳ30% accuracy, but quantitative measurements could not be obtained with the SCM. Our results demonstrate the utility of combining calibrated SSRM and SCM to delineate quantitatively the transverse cross-sectional structure of complex two-dimensional devices such as MQW BH lasers, in which traditional one-dimensional probing using secondary ion mass spectroscopy provides only a partial picture of internal device structure.

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We investigate both experimentally and theoretically the dynamics of a semiconductor laser with optical feedback in the low-frequency fluctuation regime. First we demonstrate that low-frequency fluctuations can be observed for both single and multimode operation of a semiconductor laser with optical feedback. The analysis of the fast dynamics associated with this low-frequency instability is well described by single-mode rate equations. In the multimode regime, fast pulsation is observed in every laser mode. In this case the fluctuations in total intensity are much smaller than those in the intensity of each individual mode, This indicates the presence of anticorrelations dynamics at high frequency between the different laser modes. (S1050-2947(99)08307-9)

We analyse the sensitivity of quantum dot semiconductor lasers to optical feedback. While bulk and quantum well semiconductor lasers are usually extremely unstable when submitted to back reflection, quantum dot semiconductor lasers exhibit a reduced sensitivity. Using a rate equation approach, we show that this behaviour is the result of a relatively low but nonzero line-width enhancement factor and strongly damped relaxation oscillations.

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