Scaling the Output Power of Monolithic Phase Locked Arrays of Quantum Cascade Lasers
Abstract
Scaling the coherent power of mid infrared (IR) emitting quantum cascade lasers (QCLs) to the multi watt range remains a important objective, for applications such as remote sensing of pollutants and explosives. Phase locking multiple lasers using resonant leaky wave coupling in linear arrays of antiguides has been successful in the near infrared (IR) spectral region, in that watt range peak pulsed and continuous wave (CW) near diffraction limited (D.L.) powers have been demonstrated when the resonance condition was met. These devices are in fact high index contrast (?n = 0.08 0.10) photonic crystal (HC PC) structures that allow global coupling between all array elements and, in turn, operate in a single lateral spatial mode corresponding to a photoniccrystal, band edge state. Achieving the resonance condition also leads to nearly uniform near field intensity profiles for the array resonant modes, thus preventing multi moding, due to gain spatial hole burning, at high drives above threshold. Three element phase locked arrays of ~5.3 ?m emitting QCLs, fabricated by a two step MOCVD process, have demonstrated pure diffraction limited beam operation to 5.3 W peak pulsed power. The in phase array mode observed is in excellent agreement with simulations based on the actual device dimensions, thus indicating that resonant leaky wave coupling occurs. Further coherent power scaling is expected by increasing the number of array elements and optimizing the geometry. Reduced device heating and thermal management is needed for achieving QCW-CW operation with high beam quality. In the proposed work, we address the challenges remaining to develop high brightness arrays with multi watt (>5 W) QCW-CW average output powers. Scaling the array aperture will also enable high peak output powers (> 15W) under short pulse operation.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910385
Entities
People
- L. J. Mawst
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Wisconsin System