Ag. Plyavenek, COMBINED EFFECT OF CARRIER HEATING AND CARRIER TRANSPORT ON THE INTENSITY MODULATION RESPONSE OF QUANTUM-WELL LASERS, Optics communications, 113(1-3), 1994, pp. 259-271
A model is proposed for high-speed modulation dynamics of quantum well
(QW) lasers which includes the effects of hot carriers, hot phonons,
carrier transport across a separate confinement heterostructure, carri
er capture into QW and carrier emission from QW. It is shown that an e
ffective potential barrier height and the carrier density in QW can be
critical factors for the direct modulation performance of high-speed
QW lasers. In the case of large carrier density and high degree of the
confinement of phonon modes, there exists a threshold effective barri
er height for rapid decrease in the modulation bandwidth. The microsco
pic origin of this dynamic behaviour of QW lasers is attributed to a m
ultiplicative effect of carrier heating and carrier transport. At high
modulation frequencies, in addition to the multiplicative effect, car
rier injection heating influences strongly on the intensity modulation
response resulting in increase of the modulation bandwidth under larg
e band-gap offsets. Simple expressions for a time constant for electro
n temperature relaxation and a phonon number modulation factor are der
ived. It is demonstrated that these quantities depend strongly on the
carrier density and the degree of the confinement of phonon modes.