Monolithically integrated multi-section semiconductor laser by selective area quantum well intermixing

In this work, we report the use of dielectric capping layer of TiO₂ to selectively suppress thermal interdiffusion of an InGaAs/GaAs quantum well laser structure. Large differential wavelength shift of ~ 25nm has been obtained across the same wafer between the uncapped and capped regions which is promising for achieving monolithic integration of multi-section semiconductor laser consisting of a gain, a phase and a passive waveguide sections.