PROPOSED ENHANCEMENT OF SINGLE-MODE OPERATION IN VCSELS USING DIFFUSED QUANTUM-WELL STRUCTURE

The use of interdiffused quantum wells to enhance single transverse mo de operation in vertical cavity surface emitting semiconductor lasers is proposed and analysed theoretically. It is found that by introducin g a step diffused quantum well structure inside the core region of a q uantum-well active layer, the influence of self-focusing (due to carri er spatial hole burning and thermal lensing) on the profile of transve rse modes can be minimized. Therefore, stable single-mode operation in vertical cavity surface emitting lasers can be maintained.