A Compact Four-Wavelength Quantum-Cascade Laser Source

Abstract

A four-wavelength quantum-cascade (QC) laser source that operates using a single current channel is presented. The source includes two different heterogeneous cascade QC lasers, one with emission wavelengths of 7.0 mum and 11.2 mum, and the other with 8.7 mum and 12.0 mum . For 3.0-mm and 3.5-mm cavity lengths, QC lasers with emission wavelengths of 8.7, 11.2, and 12.0 mum have threshold current densities within less than a factor of 2, which allows them to be conveniently driven in series by a single current source.