K. Obermann

TL;DR: In this paper, the authors define general parameters that are of relevance for signal processing applications and show how basic experiments and general simulation procedures can be used to determine optimum operating conditions for the intended applications.

TL;DR: In this paper, an analytical theory describing all-optical wavelength converters based on cross-gain modulation (XGM) in semiconductoroptical amplifiers is derived, which consists of two parts: a large-signal analysis yielding the transmission function for the signal, and a small signal analysis in order to describe the transformation of the signal and probe intensity noise.

Abstract: This paper deals with a general problem concerning semiconductor-laser amplifiers used for frequency conversion. The amplified spontaneous emission (ASE) of a saturated amplifier is investigated experimentally and theoretically. An analytical solution accounting for the spatial dependence of the inversion parameter as well as the spectral dependence of the ASE is derived. Hence, the results can be applied to arbitrary saturation conditions and frequency shifts. Our theory is applied to frequency converters based on four-wave mixing and is found to be in good agreement with both the numerical results and the experimental data. In order to quantify the performance of a frequency converter, a noise figure is defined and shown to be strongly dependent on the frequency detuning and the power of the input waves.

TL;DR: In this paper, the authors investigated theoretically the effect of amplified spontaneous emission (ASE) on the spatial distribution of the carrier density and derived measures of the semiconductor optical amplifier performance, such as gain, saturation power and noise figure.

TL;DR: In this article, an analytical expression for the turn-on delay probability density function (pdf) of single-mode lasers biased below threshold is derived, which is in good agreement with results based on computer simulations and measurements.