SPECTRAL LINEWIDTH AND LINEWIDTH ENHANCEMENT FACTOR IS 1.5-MU-M MODULATION-DOPED STRAINED MULTIPLE-QUANTUM-WELL LASERS

A study of the linewidth enhancement factor (alpha-parameter) of 1.5-m u m modulation-doped strained multiple-quantum-well (MQW) lasers is re ported. The alpha-parameter was effectively decreased with increasing negative detuning. At a detuning of -30 nm, the alpha-parameter can be reduced to less than 1 by 1x10(18) cm(-3) p-type modulation doping an d 1.4% compressive strain in a Fabry-Perot laser. Applying this struct ure to a distributed feedback (DFB) laser, we investigate the dependen ce of the linewidth characteristics on the alpha-parameter. Finally, i n the DFB laser with the cavity length of 1500 mu m, the minimum spect ral linewidth is lowered to 80 kHz at an output power of 40 mW.