Abstract

Quantum cascade lasers (QCL) arc fundamentally new in that: (1) their wavelength can be tailored over a wide range (so far from 3.4 µm to 21.5 µm and in the future from 1 to 100 µm) using the same combination of materials (e.g. All - nAs/GaInAs lattice matched to InP) by a suitable choice of the active layer thicknesses (a few nm), (2) their optical power is greatly enhanced by the cascade effect (one injected electron creates 25–100 photons in traversing the active region depending on the number of stages). These devices invented at Bell Labs in 1994, now outperform all other mid-ir semiconductor lasers in peak and cw optical power (with pulse peak power approaching 1 W at 300 K and cw powers >0.5 W at 80 K and cw operating temperatures now already in the range of thermoelectric coolers), and broad (up 150 nm) single mode tunability with >30 dB side mode suppression ratio.^1,2 QC lasers are presently available commercially from Applied Optoelectronics Inc. based in Sugarland, Tx, to which Lucent Technologies licensed its QC laser technology.

© 2001 Optical Society of America