3D Diode-Cross-Coupled Tapered Lasers for Kilowatt-Class, Chip-Scale, Laser Diode Phased Arrays

Based on promising results obtained under our Phase 1 SBIR contract, nLIGHT wishes to proceed with a Phase 2 program. In the proposed program, nLIGHT will continue the development of high power, single-lateral-mode tapered diode lasers. nLIGHT has identified fundamental limitations to the operation of tapered diode lasers and proposes novel design and fabrication process improvements which directly address these limitations. Prof. Eric Johnson at the University of North Carolina – Charlotte (UNCC) made significant progress towards the development of the MOPA phase-locked array in Phase 1. Using tilted gratings to couple laser emission out-of-plane while simultaneously providing single-mode laser operation, UNCC demonstrated coherent emission from multiple surface-emitting out-couplers in the master oscillator design. This collaboration will be continued, and proof-of-concept phase locking of multiple tapered power amplifiers will be demonstrated by Prof. Johnson’s group. nLIGHT also believes the development of high-power, single-transverse-mode tapered diode lasers will enable a new generation of high brightness pump sources for a variety of applications, such as pumping kilowatt-level single-mode fiber lasers. Therefore, leveraging the results of the development proposed herein, nLIGHT will deliver to DARPA a prototype wavelength-stabilized pump module operating at 976 nm, capable of delivering 50 W in a 100-micron-core fiber.