Measurement of Gain Saturation Coefficients in Strained-Layer Multiple Quantum-Well Distributed Feedback Lasers

Gain saturation coefficients of unstrained- and strained-layer multiple quantum-well lasers were measured experimentally. These coefficients were higher in lasers that had compressive strain in their active-layer wells: 2.45 x 10-17 cm3 with unstrained wells and 12.6 x 10-17 cm3 with strained wells. The higher gain saturation coefficient in lasers with strained active-layer wells is related to their higher linear TE mode gain coefficient. The linearity factor (K factor) between a laser's damping constant and the square of the laser's resonant frequency decreased slightly with introducing the strain in laser's active layer wells. This factor, however, took the value of about 0.2 x 10^-9 s for each of these lasers. The α parameter of these lasers was also estimated: 3.1 for an unstrained-layer multiple quantum-well laser and 1.1 for a laser with compressive strain in the active-layer wells.