Simulation of temperature dependent modulation response in multi-quantum-well lasers

We study the temperature dependence of the modulation response in InGaAsP/InP multi-quantum well (MQW) lasers through detailed simulations. The small signal modulation response is simulated including carrier transport, capture of carriers into the quantum wells, quantum mechanical calculation of the levels and optical gain in the wells and the solution of the Helmholtz equation for the optical mode. The temperature dependence of the relevant physical quantities is included and the simulations are performed self-consistently. The small signal response is analyzed to extract an effective differential gain for 1.3mum devices. The simulated resonance response is in good agreement with RIN-measurements of buried heterostructure lasers in a temperature range between 300K-360K. The interplay of carrier transport through the MQW active layer and the coupling to the photons has a significant impact on the modulation response. Although complex, the most significant effect on the resonance frequency comes from the inhomogencous carrier distribution among the quantum wells, which can be reduced to an approximate expression for the effective differential gain.