Characterization and modelling of distributed feedback diode lasers

The purpose of this work was two fold, to experimentally determine the temperature dependence of the rate equation parameters and to develop engineering models based upon measurements, for a GaInAsP double heterojunction distributed feedback laser. In addition, a uniform test methodology for the investigation of laser diodes was developed.;The theory and models were based on a rate equation formalism which included a non-linear gain compression term and the important recombination processes. Direct measurement of operational characteristics at different temperatures was used to determine all the rate equation parameters and their temperature dependence.;The measurements performed were DC voltage-current (V-I), light-current (L-I) and spectral emission, and microwave AM modulation. The L-I characteristics yielded the external quantum efficiency and the threshold current. The spectral measurements gave the side-mode supression-ratio and the spontaneous emission factor.;A novel DC characterization technique was established to aid in the development of the laser model. Using a nonlinear optimization algorithm, the ideal diode equation parameters were found for measured V-I data. Rapid increases in the saturation current with temperature were attributed to heterobarrier leakage. It was also found that this V-I characterization can be used to find the threshold current independent of optical measurements.;Using the rate equations, a small signal circuit model was derived. By direct optimization of the rate equation parameters using the circuit model, in combination with the parameters determined from the DC measurements, it was found that the remaining unknown parameters were uniquely defined.;In order to find the response of the laser correctly, a model for the packaging parasitics and response of the p-i-n detector were measured and modelled independently.;Most significantly, the gain coefficient was found to decrease 50% over a 40;Finally, a large signal model was derived based on the rate equations and example simulations were performed for a laser diode to find the effect of temperature on the optical response.