N251-031 TITLE: Advanced Beam Control and Wave Slap Mitigation

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy (DE);Microelectronics

OBJECTIVE: Develop an advanced beam control system on a mast mounted single 12-inch aperture beam director that mitigates wave slap and controls laser emissions, by accurately pointing to and tracking targets.

DESCRIPTION: The Navy is seeking an advanced beam control system for free space optical (FSO) communication, light (laser) detection and ranging (LIDAR), laser systems, and imaging, while maintaining a stable line-of-sight with passive and active compensation of optical beam and imaging jitters. A beam control system must also mitigate environmental effects such as wave slap on the beam director and safely control the firing of laser beam when encountering wave slaps in a timely manner. Currently, there is no government or commercial beam control system for detecting incoming rogue wave and safely controlling the emission of the laser while reliably maintaining a beam control loop for accurate imaging, tracking, or pointing of a laser beam on targets. Typical disturbance sources contributing to optical jitter include platform vibration, structural flexibility, dynamic loading, and acoustics. The beam control system should be designed to minimize and compensate for optical jitter from those various disturbance sources. A well-designed optical jitter control system not only increases the effectiveness of the laser pointing system on targets, but also enhances the imaging and tracking capabilities that will share the same optical path. In order to have a very accurate beam control system, the conventional alignment, which is based on mechanical system alignment between beam director and target line of sight, needs to be very accurate under mechanical jitter, atmospheric turbulence, target motion, etc. However, this method is relatively low speed and requires a very stable platform. To avoid such problems, in this SBIR topic the Navy seeks an innovative high speed and high precision beam steering technology to compensate for any of the above disturbances from mechanical jitters, atmospheric turbulence, phase correction errors, etc.

Detailed requirements for the beam control system:

• Laser Power: > 100 kW average

• Elevation Range: -10 degrees to +85 degrees

• Azimuth Range: 360 degrees

• Target Acquisition Course Field of View (FOV): Wide (50 degree), Medium (8 degree FOV), Narrow (2 degree FOV)

• Target Acquisition Fine: < 1 degree FOV (with zooming capability)

• Target Acquisition Sensors: Visible (VIS), Short Wavelength Infrared (SWIR) and Medium Wavelength Infrared (MWIR) sensors with common FOV

• Target Feedback Control System with Target/Track Illumination Laser (TIL): As a probe laser and BIL (beacon illumination laser)

• Target Tracking: Demonstrate accurate and stable target tracking with positive feedback target lock-in, short acquisition time, and multiple target selection

• Wave Slap: Detection and mitigation within 10 milli seconds or less and closed loop with fire control

• Pointing Accuracy: 1 microradian (relative to inertial reference) closed loop using pulse probe laser

• Shock Tolerance: Structures and components must remain operable through 20G shock acceleration

• Beam Control System Housing: Pressurized 1 atm N2 gas for reduced condensation along the beam control optical path

• Beam Control System: Shall have Athermalization of the optical system

• Beam Director/Periscope Housing: Withstand fluid pressure of greater than 500 psi without leakage; and isolate components at maritime environment

• Volume: Compatible with existing/future Navy platform mast configurations (17" x 17" x 45")

• Target illumination pulse laser with Deformable Mirror (DM): Include in design for adaptive wave-front, phase correction of laser beam due to atmospheric turbulence; Polarized pulse laser (as probe laser, LIDAR, TIL) can be used for the advanced beam control target detection and laser beam control on target of interest.

• Co-bore sighting: shared by imaging, TIL and laser

• Fast Steering Mirror: Include in design for correction of jitter from on-board vibrations and base motion compensation.

• LIDAR: Target ranging to provide information to beam control system for FOV and target tracking for beam delivery onto target.

• Imaging band: Vis, SWIR and MWIR; Use of Artificial Intelligence technique and multiband imaging for improving target detection, tracking, and pointing of the laser beam under different atmospheric condition is recommended.

• Optical path beam scattering detection system: to monitor beam path inside the beam control system in real time with laser fire control for safety.

Many technical challenges need to be solved before a laser system can be integrated onto a platform mast configuration. One of these issues involves building and demonstrating a compact and agile beam control system. Beam Control systems developed so far for land-based or airborne use are too large for to integrate them for Navy platform mast configuration use and are not submersible. Adapting beam control system designs for the Navy platform mast configurations requires greatly reduced space, weight, and volume while the overall system continues to maintain extremely accurate movement of the optical elements so that the laser intensity is maintained on target for the application of free space optical communication, imaging and tracking, LIDAR, and other laser system. Furthermore, system affordability must be addressed upfront as a major design consideration.

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.

PHASE I: Develop a concept and demonstrate the feasibility of the advanced beam control system and identify the risk associated for mast mounted configuration to include integration of both TIL and laser beams. Modeling and simulation shall be used to determine feasibility and to assist with providing an initial assessment of performance under marine environment. Parameters that will demonstrate feasibility are identified in the Description section. The Phase I Option, if exercised, would include the initial layout and design to build the prototype in Phase II.

PHASE II: Develop and deliver the full-scale prototype beam control system with wave slap detection closed loop with beam fire control, target acquisition, target detection, stable optical communication, and power delivery on target with high precision based on the requirements outlined in the Description. If the Phase II Base is successful and is able to meet all initial objectives as outlined, the Phase II Option I and Option II will be exercised for the full mast mounted beam control system delivered to NAVY for test and evaluation.

It is probable that the work under this effort will be classified under Phase II (see the Description section for details).

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the advanced beam control system into submarine laser and imaging programs for target tracking, and laser beam delivery on target. Validate, test, qualify, and certify the system for Navy use at the Navy facility.

Free-space optical (FSO) communications is an area of dual use for this technology.

REFERENCES:

1. Barchers, J.D. "Modeling of laser beam control systems using projections onto constraint sets." Proceedings of the 2004 American Control Conference, Vol. 2., Boston, MA, USA, 2004, pp. 1493-1498. https://ieeexplore.ieee.org/document/1386787

2. Kim, Jae Jun; Nagashima, Masaki and Agrawal, Brij. N. "Optical Beam Jitter Control for the NPS HEL Beam Control Testbed." Naval Postgraduate School, Monterey, CA. https://nps.edu/documents/106865520/106917544/Optical+Beam+Jitter+Control+-DEPS+Paper.pdf/9b787113-9c99-4827-ac88-08496dc498e1?t=1458153910000

3. Ganesan, A.R.; Arulmozhivarman, P.; Mohan, D. and Gupta, A.K. "Laser Beam Steering Control System for Free-Space Line of Sight Optical Communication." IETE Journal of Research, 52(6), 2006, pp. 417-424. https://doi.org/10.1080/03772063.2006.11416482, https://www.tandfonline.com/doi/abs/10.1080/03772063.2006.11416482

4. Kim, B.S.; Gibson, Steve and Tsao, Tsu-Chin. "Adaptive Control of a Tilt Mirror for Laser Beam Steering." Proceedings of the 2004 American Control Conference, Boston, MA, USA, 2004, pp. 3417-3421, vol.4. doi: 10.23919/ACC.2004.1384437, https://ieeexplore.ieee.org/document/1384437

5. "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

KEYWORDS: Beam control system; Wave slap detection; Free Space Optical; FSO; Adaptive optics; imaging and periscope system; target illumination laser (TIL)

TPOC 1: Tariq Manzur
(401) 832-6887
Email: [email protected]

TPOC 2: Jae Choe
(202) 487-642
Email: [email protected]

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