Wide temperature range cw operation of vertical-cavity surface-emitting lasers with a GRINSCH structure and continuously graded mirror heterointerfaces

A systematic and comparative study of the temperature dependence of the threshold current, threshold voltage, and output power of vertical-cavity surface-emitting lasers (VCSELs) is presented to discuss the factors that limit their temperature range for cw operation. To achieve high-performance for VCSELs, the position of the lasing mode must be in close proximity to (within +/- 5nm of) the gain peak under cw operation. In addition, by introducing continuously graded hetero-interfaces throughout the VCSEL structure, the effect of thermal self-heating is reduced. The combination of low thermal dissipation and alignment of the cavity mode to the gain peak resulted in VCSELs with excellent operating characteristics over a broad range of temperatures, including a thermally stable threshold voltage, and a very wide temperature range for both pulsed (100K to 540K) and cw (100K to 410K) operation.