High Power Fiber Amplifier (HPFA) Power Scaling

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy (DE) The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Develop and demonstrate novel concepts for scaling individual high power fiber amplifiers (HPFAs) to power levels >10 kW with good beam quality. DESCRIPTION: DARPA requests SBIR development on HPFAs to demonstrate single amplifier output beyond 10 kW through means fundamentally capable of scaling to multiple 10s of kW. Initial efforts may focus on critical component development or may begin directly with system-level demonstrations, based on the maturity of the proposed concept. Emission must maintain good beam quality to maintain suitability for direct long-range transmission and/or additional scaling through existing beam combination methods. Single HPFA performance goals: Power: > 10 kW Wavelength: 0.8 = = 2.2 m Linewidth FWHM: < 100 GHz FWHM Linewidth total in-band power: < 300 GHz E-O efficiency: > 35 % Beam quality (M2): > 1.2 RMS phase noise above 100 kHz: < /40 Mode field diameter (MFD): 10 = MFD = 100 m PHASE I: Phase I is a 6-month effort aimed at delivering evidence that the proposer's approach is viable. This may include analytical studies, digital modeling, or experimental demonstration.Phase 1 fixed payable milestones should include: Month 1: Kickoff meeting with presentation of performer concept, Phase I goals, and approach Month 3: Report and presentation showing preliminary results and projected performance Month 6: Report and presentation showing results, projected performance, and Phase II plan PHASE II: The content below applies to both Direct-to-Phase II (DP2) and Phase II proposalsThe Base period of Phase II is targeted for procurement of long-lead items and initial subscale concept demonstration. Fixed payable milestones should include: Month 1: Kickoff meeting with presentation of performer concept, Phase II goals, approach, and schedule Month 3: Preliminary subscale concept demo design, procurement plan, and updated schedule Month 6: Completed subscale concept demo design, test plan, and updated schedule Month 9: Subscale concept demo results and Phase II Option plan The Option period of Phase II is targeted for power scaling. Fixed payable milestones should include: Month 12: Preliminary demo with pump power > 3 kW and updated schedule Month 15: Intermediate demo with pump power > 9 kW and updated schedule Month 18: Final demo with pump power > 15 kW, presentation of final results/findings, and recommendations for future power scaling Performers shall have quarterly meetings with DARPA where results supporting payable milestones are presented. These meetings may occur as a telecom or at performer facilities, as requested. Direct-to-Phase II (DP2) Direct-to-Phase II (DP2) offerors must demonstrate existing technical maturity and feasibility of their approach through preliminary results, which can include analytical studies, digital modeling, and reports outlining prior work. Proposals should clearly articulate the innovation and potential impact of the proposed technology and outline a clear transition path to Phase III. Feasibility cannot be based on prior SBIR/STTR efforts. PHASE III DUAL USE APPLICATIONS: HPFAs are dual-use technology. Commercial applications focus primarily on machining and manufacturing where HPFAs are employed for cutting, welding, annealing, metal additive manufacturing, and other complex materials processing. In addition to manufacturing roles for defense applications, HPFAs may be deployed in capabilities for remote sensing, electronic attack, and directed energy weapons. REFERENCES: Jay W. Dawson, Michael J. Messerly, Raymond J. Beach, Miroslav Y. Shverdin, Eddy A. Stappaerts, Arun K. Sridharan, Paul H. Pax, John E. Heebner, Craig W. Siders and C.P.J. Barty, Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power, Opt. Express 16, 13240 - 13266 (2008). KEYWORDS: Fiber amplifiers, fiber lasers, directed energy, optics, optical beam combining