Semiconductor optical gain

About: Semiconductor optical gain is a research topic. Over the lifetime, 5997 publications have been published within this topic receiving 96505 citations.

Noise in nearly-single-mode semiconductor lasers.

Abstract: We report the results of a numerical study of nearly-single-mode semiconductor lasers. The stochastic nonlinear dynamical equations of the field and population inversion are integrated and the intensity fluctuations and line shapes of the laser are investigated. The second mode affects the coherence of the light output appreciably, particularly near the laser threshold regime. The accuracy of the linearized theory for a single-mode laser is tested from far below to far above threshold. It is found to be very accurate both far below and far above threshold, but significant discrepancies are seen in the threshold region. We automatically include the coupling of the intensity and phase fluctuations in the line-shape calculations, resulting in the experimentally observed asymmetry of the relaxation oscillation sidebands. The numerical technique developed here is easily applicable to multimode lasers and is shown to be a convenient and powerful probe of the coherence properties of semiconductor lasers.

Effect of saturation caused by amplified spontaneous emission on semiconductor optical amplifier performance

Abstract: The authors have investigated theoretically the effect of amplified spontaneous emission (ASE) on the spatial distribution of the carrier density. Measures of the semiconductor optical amplifier (SOA) performance, such as gain, saturation power and noise figure are derived. It is shown that the saturation due to the ASE strongly affects the SOA performance for device lengths > 500 µm. The results are compared with experimental data and found to be in good agreement.

Optical gain in materials with indirect transitions

Abstract: Based on a simple two-level system, we discuss optical gain in materials with indirect optical transitions. We show that contrary to direct materials the absolute value of the negative absorption coefficient, which describes the optical gain, can be orders of magnitude larger in indirect semiconductors than the positive absorption coefficient measured under equilibrium conditions. These results are in contrast to previously published work and suggest that the question as to whether laser operation based on band–band transitions in bulk crystalline silicon is possible or not, in principle, needs to be readdressed. In addition, it is shown that indirect optical transitions can provide negative absorption, i.e., optical gain without an electronic population inversion.

Four-wave mixing among short optical pulses in semiconductor optical amplifiers

Abstract: We describe the dependence of four-wave mixing conversion efficiency among short optical pulses in a semiconductor optical amplifier We show a strong dependence on pulse shape and pulse overlap, predicted theoretically and confirmed in experiments >

Measurement of optical two-photon gain in electrically pumped AlGaAs at room temperature.

Abstract: We demonstrate experimentally two-photon gain in semiconductor structures, shown previously only in dilute atomic systems. Two-photon gain is directly observed and characterized in electrically pumped room-temperature semiconductor devices, in good agreement with theory. The semiconductor structure was designed to enhance the two-photon interaction and reduce parasitic effects. The nonlinear two-photon amplification is studied directly by examining the current dependence of the optical intensity growth, and indirectly by monitoring the reduction in one-photon emission due to two-photon transitions above transparency.