A. Schonfelder et al., THEORETICAL INVESTIGATION OF GAIN ENHANCEMENTS IN STRAINED IN0.35GA0.65AS GAAS MQW LASERS VIA P-DOPING/, IEEE photonics technology letters, 6(4), 1994, pp. 475-478
We present a systematic theoretical investigation of the influence of
p-doping on the gain characteristics of strained In0.35Ga0.65As/GaAs m
ultiple-quantum-well (MQW) lasers, and compare the results with those
obtained experimentally from devices with record 30 GHz modulation ban
dwidths. Experimentally, the combination of p-doping and strain has be
en found to lead to only a small increase in the differential gain, pa
rtial derivative g/dn but a large decrease in the non-linear gain coef
ficient, epsilon; this behaviour has been theoretically accounted for
by a doping-induced decrease in the intraband relaxation time, tau(in)
. The theoretical investigations reveal that the assumption of a const
ant intraband relaxation time is not sufficient to describe the role o
f p-doping in the above devices, and highlight the importance of utili
zing an appropriate lineshape function for the modelling of high speed
laser modulation behaviour.