Modulation bandwidth optimisation for unipolar intersubband semiconductor lasers

A rate equation analysis of the direct-current modulation response of intersubband semiconductor lasers is reported using a rate equation model for a triple quantum well structure. It is demonstrated that terahertz modulation bandwidths may be achievable due to the picosecond carrier lifetimes which are characteristic of such structures, A novel feature of the modulation response of intersubband semiconductor lasers is the existence of an optimum output power for achieving maximum modulation bandwidth in a given structure. Further optimisation of the modulation performance is achievable via appropriate design of the coupled quantum well structure.