Tm:fiber-Based, Reduced Eye-Hazard Laser

Building on the work carried out in the Phase I program and the significant advances that Q-Peak has made in the development of high-power Tm:silica fiber lasers under HEL-JTO funding, we propose to build two laboratory systems under this Phase II program in which we will demonstrate the following: • a 150-W, single-frequency, single-spatial-mode, polarized Tm:fiber amplifier; • an actively phase-locked array of seven Tm:fiber amplifiers. We believe that these two objectives represent important next steps in the development of high-power Tm:fiber laser technology that will be useful specifically for Directed Energy (DE) applications. The demonstration of a 150-W Tm:fiber laser that suppresses SBS and yields a single-frequency, single-spatial-mode output beam represents a significant advance over the state-of-the-art and will provide a solid technical basis for the design of the seven-fiber, actively locked array that we intend to build and test as the second objective in this project. Demonstration of this seven-fiber array begins the task of developing the hardware needed to scale Tm:fiber lasers to the levels ultimately needed for DE applications. It specifically addresses the need for near-diffraction-limited, single-frequency, polarized output beams at high-power levels, which are the properties needed for actively phase-locked coherent summation of fiber-laser arrays.