Theoretical and experimental investigation of IV-VI mid-infrared multiple quantum wells vertical cavity surface emitting lasers.

Abstract

Lateral mode suppression techniques other than reduction of pump spot size need to be developed. Air-post pillar structure and electrically pumped configuration certainly need to be investigated.

Throughout this research, several simulation programs have been developed. These software packages can utilize further developments of mid-infrared lasers. Also, a working prototype of optically pumped ECT-VCSEL was built, as described in chapter 6. However, the heat dissipation issue is still the prime obstacle for room temperature CW operation.

Based on our findings, further fabrication development is necessary to improve the laser performance. Other alternative approaches such as edge emitting source with the same ECT configuration also need to be explored.

Epi-down (wherever applicable) is a key design factor for any mid-infrared laser regardless of the design. Due to the direct contact of the active region to the heat-sink, this configuration provides the highest possible heat dissipation.

The multilateral modes and poor heat dissipation are the main obstacles of room temperature operation. These issues were addressed by using an external cavity configuration and by the reduction of the pump spot size to 90mum. Nevertheless, these challenges present opportunities for the ongoing research.