PURE EFFECTS OF STRAIN IN STRAINED-LAYER MULTIPLE-QUANTUM-WELL LASERS

Pure effects of strain in strained-layer InGaAs-InGaAsP multiple-quantum-well (MQW) Fabry-Perot (FP) lasers operating at 1.5 mum region are measured separately from the quantum effects by using lasers whose active layer wells have the same thickness but different amounts of strain. The gain peak wavelengths of transverse electric (TE) and transverse magnetic (TM) modes increase and the difference between TE-and TM-mode gain peak wavelengths also increases when compressive strain is introduced. The differential gain coefficient and the gain saturation coefficient of the lasers are determined by measuring relative intensity noise (RIN) spectra and are found to increase with increasing the compressive strain. The K factors of the lasers are also determined from the relation between the damping constant and the resonant frequency square. The factor shows slight increase when the compressive strain increases. The a parameter of these lasers decreases when compressive strain is introduced.