QUANTUM-CASCADE LASERS: High-power QCL MOPA array aims for spectroscopy

摘要

For use in mid-infrared (mid-IR) spectroscopy, multiwavelength arrays of single-wavelength quantum-cascade lasers (QCLs) can in some cases serve as an alternative to single but tunable QCLs. While the disadvantage is that only certain wavelengths are available, the advantage is purely electronic addressing of different wavelengths. Federico Capasso's group at Harvard University (Cambridge, MA), along with Christine Wang of MIT Lincoln Laboratory (Lexington, MA), has compared two of their own designs for multiwavelength QCL arrays. Both rely on master-oscillator power-amplifiers (MOPAs) to boost the power, but each one differs in the details of the MOPAs' distributed-feedback grating arrangements (dubbed Array 1 and Array 2 for the study). The researchers have shown that the more recent Array 2 design is superior.