Origin of nonlinear gain saturation in index-guided InGaAsP laser diodes

Abstract
The spectrum of nonlinear gain saturation of InGaAsP diode lasers with a buried heterostructure is measured by means of modulation spectroscopy. The underlying physical processes are identified through comparison with theoretical spectra. At the laser line, contributions to the coefficient of self-saturation by spectral hole burning (1.6×10−17 cm3) and carrier heating (1.1×10−17 cm3) of comparable magnitude are found.