Low‐threshold 1.25‐μm vapor‐grown InGaAsP cw lasers

Vapor‐grown double‐heterojunction lasers of InGaAsP/InP have been prepared with cw room‐temperature threshold currents of 85 mA and differential quantum efficiencies exceeding 50% at 1.25 μm. From several lasers, fundamentaal‐lateral‐ and fundamental‐longitudinal‐mode operation have been observed over moderate current ranges. Over 1000 h of room‐temperature cw operation has been observed to date without significant degradation.