EFFECT OF STRAIN ON THE RESONANT-FREQUENCY AND DAMPING FACTOR IN INGAAS/INP MULTIPLE QUANTUM-WELL LASERS

The intensity noise of strained In(x)Ga(1-x)As/InP multiple quantum well (MQW) lasers is measured for three types of strain: tensile strain (x = 0.48), no strain (x = 0.53), and compressive strain (x = 0.65). From a comparison between the measured noise power spectral density and the theoretical one, the resonance frequency and the carrier damping factor of each type of lasers are calculated. Although compressive strained MQW lasers show about 10% increase in resonance frequency compared to those of tensile strained and unstrained lasers, this increase is smaller than theoretically predicted. Most important, all three types of MQW lasers show about two to three times higher nonlinear gain saturation and lower maximum bandwidth than conventional double-heterostructure lasers. A solution to reduce this high damping is also discussed.