We have systematically studied the high speed performance of a 1.55 mu
m InGaAsP multiple quantum well laser diode at cryogenic temperatures
from 10 to 300 K. We show that the maximum modulation bandwidth of the
laser diode increases from 10 GHz at room temperature to over 27 GHz
at the vicinity of 100 K. Our analysis indicates that this bandwidth i
s mainly limited by the device parasitics above 100 K and carrier tran
sport below it.