Bound-to-continuum and two-phonon resonance, quantum-cascade lasersfor high duty cycle, high-temperature operation

摘要

Recent advances in quantum-cascade (QC) laser active-region designnare reviewed. Based on a rate equation model of the active region, wenshow why new gain regions. based on a two-phonon resonance or anbound-to-continuum transition exhibit significantly better performancenthan the traditional design based on a three-quantum-well active region.nThreshold current densities as low as 3 kA/cm2 at T=300 K,noperation with a peak power of 90 mW at 425 K, single-mode high-powernoperation up to temperatures above 330 K at Λ≈16 Μm andncontinuous wave operation up to T=311 K are demonstrated. QC lasers ablento operate at high duty cycles (50%) on a Peltier cooler were used in andemonstration of a 300-MHz free-space optical link between two buildingsnseparated by 350 m