Evaluation of semiconductor optical parameters for laser diodes

The small-signal modulation and noise properties (electrical voltage, optical power and phase) of laser diodes depend on ten real parameters relating to the semiconductor material employed. Among these, the phase-amplitude coupling factor α is of particular importance. These parameters are evaluated for GaAs at 0.87 μm, GaInAsP at 1.55 μm and InAsSb at 3.87 μm at room temperature. Revised expressions for the optical gain are used. The light-hole contribution, the plasma effect and band-gap shrinkage are taken into account. The latter leads to a significant reduction of α, particularly below the peak-gain frequency. The α-factors for the three materials listed above are found to be, respectively, 2.9, 3.85 and 8.3 for conventional diodes