N241-041 TITLE: High Power Optical Splitter for Laser Weapon Systems
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 a capability to efficiently split the power of a high energy laser beam into two outputs.
DESCRIPTION: The Navy is fielding a family of high energy laser (HEL) weapons designed for surface ship self-defense. As the output power of these systems has been steadily evolving, the realities of shipboard implementation are coming to the forefront. This includes issues of cost, size, weight, and power consumption on the one hand, and issues of employment and tactical effectiveness on the other. HEL weapon systems can be divided into two main sub-systems: the sub-system that generates the laser power and forms a high quality output laser beam, and the laser beam director that places and holds the beam on target. Between these two units is an optical path that is essentially lossless.
The laser generation hardware is housed below deck in an environmentally controlled space. The beam director is mounted above deck, preferably as high on the ship’s structure as practical. The complete functional independence of the two units and the lossless path between the two make this possible. It also makes it possible, in theory, to supply multiple beam directors from the same laser power source. Theoretically, this would then provide a cost-effective means for providing full coverage around the perimeter of a vessel without the need for multiple laser power sources. Currently there is no commercial capability that can split a high power laser beam.
The Navy needs a technology for splitting a high power laser beam into two separate channels (optical paths). The splitter is intended to be placed in the optical path between the laser source and beam director(s). An optical splitter that can switch the entire beam between two channels is the minimum requirement. However, a technology that can split the bream fractionally between channels is most attractive. The ratio of power split between the paths can be continuous or fixed to discrete increments but, in addition to complete switching between channels, ratios of 50/50 to 20/80 are desired. True splitting of the continuous wave power provides the greatest flexibility in operation, however, solutions that achieve average power splitting by time division of the full continuous wave beam power are acceptable provided the switching between channels occurs at a rate of at least 500 Hz. As the quality of the transmitted beam is of great importance, acceptable solutions should not degrade the beam quality of the input beam (as measured by M2) by more than 5%.
The solution must be capable of handling a minimum of 300 kW of continuous wave input power at a wavelength of 1.0 micron. As a goal, the beam splitter should have a 98% transmission efficiency (95% is the minimum acceptable). As the technology is intended for eventual deployment aboard Navy vessels, the solution should be fundamentally rugged and require no manned intervention (e.g., periodic calibration, alignment, tuning, etc.) during operation. Note that the Navy does not intend to furnish tactical or otherwise representative laser hardware for this effort. The proposed solution should therefore include the means for test and demonstration on surrogate hardware, provided as part of the solution. To verify power handling, demonstrations using scaled hardware, analysis, and comparison to proven component technologies are acceptable. A prototype (hardware and software) of the technology will be delivered to NSWC Dahlgren Division at the conclusion of Phase II.
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 32 U.S.C. § 2004.20 et seq., National Industrial Security Program Executive Agent and Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence and Security Agency (DCSA) formerly Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances. This will allow contractor personnel to perform on advanced phases of this project as set forth by DCSA 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 during the advanced phases of this contract IAW the National Industrial Security Program Operating Manual (NISPOM), which can be found at Title 32, Part 2004.20 of the Code of Federal Regulations. Reference: National Industrial Security Program Executive Agent and Operating Manual (NISP), 32 U.S.C. § 2004.20 et seq. (1993). https://www.ecfr.gov/current/title-32/subtitle-B/chapter-XX/part-2004
PHASE I: Develop a concept for an HEL beam splitter that meets the objectives stated in the Description. Demonstrate the feasibility of the concept in meeting the Navy’s need by any combination of analysis, modelling, and simulation. Analyze and predict the splitter performance, including the ability of the splitter to handle the input power required. Include in the proposed concept a means to test the technology. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.
PHASE II: Develop and deliver a prototype HEL beam splitter based on the concept, analysis, preliminary design, and specifications resulting from Phase I. Demonstration of the beam splitter technology shall be accomplished through test of a prototype in a laboratory or controlled outdoor environment utilizing surrogate lasers. At the conclusion of Phase II, prototype hardware and software shall be delivered to NSWC Dahlgren along with complete test data, installation and operation instructions, and any auxiliary software and special hardware necessary to operate the prototype.
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 Government use. Refine specific hardware, software, and operating instructions for specific Navy HEL weapons. Establish hardware and software configuration baselines, produce support documentation, production processes, and assist the Government in the integration of the beam splitter technology into existing and future HEL weapon systems.
The technology resulting from this effort is anticipated to have broad military application. In addition, there are scientific uses, specifically in high energy physics. Machining, food packaging, and solar energy are a few industries that may benefit from this technology.
KEYWORDS: Laser System; High Energy Laser; Beam Director; Laser Weapon Systems; Optical Splitter; Beam Splitter
** TOPIC NOTICE **
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|If a solution is proposed that uses a fiber splitter, with evidence of its feasibility for such extreme power levels, would it be considered or would it be rejected due to the difference in the nature of the proposed solution.
|The solicitation does not preclude any proposed solution or identify a preferred solution.
|Regarding the 2%-5% transmission loss:
I assume it is undesireable for this loss to be reflected back opposite the direction of the incoming laser beam, so as to go back into the laser, correct?
If so, then I assume there is a minimum desired angle between the direction of the loss reflected back toward the laser and the opposite of (180 degrees minus) the direction of the incoming laser beam, correct?
If so, then what is this minimum desired angle?
|1. That is correct. Counter-propagated power is highly undesirable.
2. The design of the HEL and Beam Control/Beam Director have not been completed to a level sufficient to answer this question.
|1. We have identified a commercial vendor able to provide an 8” diameter non-polarizing beam splitter with various splitting ratios in the wavelength band of interest, capable of handling 20kW/cm2. (a) Would this meet the requirements of topic? (b) Are there other areas of concern that traditional commercial solutions do not currently satisfy, other than power handling?
2. What is the duration of the laser exposure?
3. Can the laser be turned off while the beam splitter is changed? If so how long can it be turned off?
|1. I can’t provide guidance on the merits of any proposed approach or predict how any given concept will be reviewed by the evaluation team. A question I might ask in this instance would be whether or not the proposed optic is suitable in a maritime environment?
2. A duration was not established or identified in the solicitation. In general, I think it should be obvious that longer durations are more attractive.
3. Yes, the laser can be turned off. A switching time was not established or identified in the solicitation. In general, I think that it should be obvious that shorter switching times are more attractive.
|It is stated in the topic description that "Between these two units is an optical path that is essentially lossless". Is this optical path a free space or optical fiber?
|The optical path is expected to be free space. We are not aware of optical fiber that is suitable for 300kW+ cw sources.
|What is the polarization of your HEL laser beam, i.e., linear, or un-polarized?
|The HEL sources are planned to be unpolarized.
|Sir, we have 4 technical questions: