Scalable PROFA-based Talbot Array for High-Power Coherent Combining at 2 m

In Phase II of this STTR, Chiral Photonics, Inc. (CPI) proposes to develop a high-power fiber-based laser with near diffraction limited beam quality operating at a wavelength of 2 m by coherently combining up to 61 individual fiber lasers. The design of this high-power laser will be based on a Talbot cavity which will passively lock the phases of each of the individual lasers. A key component of the Talbot cavity, which will couple a large number of individual fiber lasers, will be based on CPIs pitch reducing optical fiber array (PROFA) technology. CPI will take advantage of the improvements it achieved in the performance and manufacturability of high channel-count PROFA devices achieved in Phase I. Improvements were made in the accuracy of PROFA channel positioning, mode field diameter control and fill factor, which are required for the proposed Talbot cavity coherent combiner. The prototype laser proposed for Phase II will output approximately 200 W CW, the Talbot-based design approach is scalable to kW level 2 m lasers for both air-born and ground-based systems for the Air Force. Unlike master oscillator power amplifiers (MOPA) based 2 m lasers, the Talbot laser will not require a high power isolator.