TECHNOLOGY AREA(S): Weapons

ACQUISITION PROGRAM: NAVSEA 073, Advanced Submarine Systems Development

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 section 3.5 of 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 a high-energy laser operating at 2 �m (micron) wavelength, kilowatt (kW) class amplifier design for Next Generation Submarine Warfare and Battle Space supremacy using non kinetic energy.

DESCRIPTION: The Navy is evaluating how it uses the Electro-magnetic (EM) Spectrum with an objective of gaining military advantages and achieving freedom of action across all Navy missions in support of nearwater warfare. This effort is driven by both new threats and available and emerging technologies. These technologies have the potential to vastly improve the agility and flexibility of the Navy systems by utilizing high-energy lasers for Battle Space Supremacy and Water Space Management as envisioned by the Chief of Naval Operations (CNO). The current technology for High Energy Laser (HEL) at this wavelength for kW class amplifiers is in early development. A major challenge exists for this technology to be viable for development of doped fiber for the 2 �m kW class amplifier systems. The Navy seeks to address the manufacturability, electrical-to-optical (EO) efficiency and technology risk assessment and reduction of this class of laser amplifier design.

The major advantage of this spectrum for HEL class amplifier should lead to an increase in engagement range at marine atmospheric conditions, such as scattering, thermal blooming etc., when compared to the scenario where the same power at 1 �m wavelength is used. Another advantage of this wavelength spectrum is providing operation in the eye-safe spectrum from the optical scattering from the marine wave boundary layer (MWBL) when compared to the 1 �m wavelength laser, which has higher scattering properties from MWBL. The third consideration of 2 ?m laser is the less detectability compare to current standard 1 ?m HEL system.

A major challenge to develop this technology is the development of thulium based doped double clad optical fiber design for the 2 ?m kw class amplifier system.� The second challenge is to demonstrate an EO efficient > 40% with high beam quality (M2 < 2) > 2 kW class laser module prototype system for test and evaluation at Navy lab.

The current state-of-the-art technology in the commercial or DoD arena is based on 1 �m wavelength high-energy, weapon-grade laser. The challenges of current laser technology at marine atmosphere levels are its detectability by adversaries due to its higher scattering property and that it is not an eye-safe operation in a clutter condition where friendly force or bystanders are present. The EO efficiency of the 2 �m kW laser amplifier module shall be greater than 30%. The technology shall be demonstrated through the Spectral Beam Combining (SBC) of the individual module to combine power to achieve 30 kW continuous wave output power with higher beam quality M2<2. Both the power specifications and wavelength of operation and EO efficiency will be tested at a NSWC Dahlgren, Navy HEL test facility.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. Owned and Operated with no Foreign Influence as defined by DOD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been be implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this contract as set forth by DSS and NAVSEA in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advance phases of this contract.

PHASE I: Develop a concept of 2 �m operating wavelength fiber laser/amplifier products for Navy application. Consider the Size, Weight, and Power-Cooling (SWaP-C) aspect of the amplifier for the design of the kW class amplifier. Ensure that the EO efficiency of the amplifier is greater than 30%. In Phase I company shall provide a feasibility study of the kw class 2 um amplifier design based on Model Based Engineering. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution based on by modelling and simulation. Develop a Phase II plan.

PHASE II: Develop, demonstrate, and deliver an efficient, high beam quality (M2 <2) 2kW class prototype laser module system for testing and evaluation. Evaluate the prototype laser kW class module by testing. Provide test results and analysis. Demonstrate the SBC of the individual module to combine power to achieve 30 kW output power with higher beam quality M2<2. Deliver the prototype to the NSWC Dahlgren Navy lab to evaluate the performance of the system in terms of power specifications, wavelength, beam quality and EO efficiency for a HEL prototype system that can meet Navy performance goals.
�
It is probable that the work under this effort will be classified under Phase II (see Description section for details).

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology for Navy use. For this purpose, show the scalability of power to 100kW class and beyond. The laser system will be deployed ultimately in a submarine or other Navy platform to advance the future Navy warfighting capability. Both the power specifications and wavelength of operation and electrical to optical (EO) efficiency will be tested at a NSWC Dahlgren, Navy High energy laser (HEL) test facility.

There is a potential for dual use of this system for cutting/welding, optical communication and use in space or airborne platforms. One of the most important characteristics of this wavelength is that it will be less affected by the atmospheric operation near marine wave boundary layer (MWBL) and its eye-safe operation from scattered light.

REFERENCES:

1. Fang, Q., Shi, W., Kieu, K., Petersen, E., Chavez-Pirson, A. and Peyghambarian, N. "High power and high energy monolithic single frequency 2 �m nanosecond pulsed fiber laser by using large core Tm-doped germanate fibers: experiment and modeling." Opt. Express 20, 2012, pp.16410-16420.� https://www.osapublishing.org/oe/abstract.cfm?uri=oe-20-15-16410

2. Wu, J., Yao, Z., Zong, J., Chavez-Pirson, A., Peyghambarian, N. and Yu, J. �Single-frequency fiber laser at 2.05 �m based on Ho-doped germanate glass fiber.� Fiber Lasers VI: Technology, Systems, and Applications, Proc. of SPIE Vol. 7195, 2009, 71951K. https://doi.org/10.1117/12.809482

3. Goodno, G.D.,� Book, L.D. and Rothenberg, J.E. �Low phase noise, single frequency single mode 608 W thulium fiber amplifier.� Opt. Lett. 34, 2009, pp. 1204-1206. https://doi.org/10.1364/OL.34.001204

4. Ehrenreich, T., Leveille, R., Majid, I., Tankala, K., Rines, G. and Moulton, P.F. �1-kW, all-glass Tm:fiber laser.� Fiber Lasers VII: Technology, Systems, and Applications, 2010.� https://www.researchgate.net/publication/267765753_-kW_All-Glass_Tmfiber_Laser

5. Simakov, N., Hemming, A., Clarkson, W.A., Haub, J. and Carter, A. �A cladding-pumped, tunable holmium doped fiber laser.� Opt. Express 21, 2013, pp. 28415-2841.� https://www.osapublishing.org/DirectPDFAccess/ACE7EF3A-E158-C7C9-548BFD1656773E0D_274436/oe-21-23-28415.pdf?da=1&id=274436&seq=0&mobile=no

KEYWORDS: HEL; High Energy Laser; Optical Amplifier; Optical Efficiency; Spectral Beam Combining; SBC; Electro Magnetic Spectrum; Marine Wave Boundary Layer; MWBL