N212-126 TITLE: GHz Optical Underwater Detection Receiver

RT&L FOCUS AREA(S): General Warfighting Requirements (GWR)

TECHNOLOGY AREA(S): Sensors;Weapons

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 wide bandwidth (GHz), multi-element optical receiver to enable the extraction of both reflectivity and range features of objects in water. The optical receiver should have high sensitivity at visible wavelengths and sufficient dynamic range to detect signals in high clutter environments.

DESCRIPTION: Time resolved detection is needed in underwater imaging to distinguish between desired object returns and unwanted environmental clutter. Sufficient resolution (< 5cm) in both space and time is required to identify underwater threats. While techniques have been developed on the transmitter side to create high bandwidth optical interrogation signals, the receiver side has been limited to single element receivers that must be mechanically scanned to image a scene. Such a configuration is not compatible with moving platforms. While time of flight cameras have been developed for the automotive industry, these cameras do not have the time resolution necessary to operate in high clutter environments. A multi-element, wide bandwidth optical receiver is needed to achieve the benefits of high time resolution with a spatially resolved optical detector.

PHASE I: Develop a concept for a multi-element (>10,000), wide bandwidth (1GHz) optical receiver with optical sensitivity in the blue-green wavelengths. The concept should include methods to simultaneously sample the optical receiver elements with sufficient speed to enable the processing of GHz-bandwidth signals. Areas of technical risk and mitigation methods should be identified. 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: Design, build and test the multi-element, wide bandwidth optical receiver developed in Phase I. Test the developed optical receiver with wide bandwidth, chirp-modulated optical signals to verify its capability to recover high bandwidth signals with multiple receiver elements.

PHASE III DUAL USE APPLICATIONS: Support the Government in transitioning the optical receiver to fielded laser imaging systems. Dual use opportunities include unmanned underwater vehicle (UUV) surveying and automotive light detection and ranging (LIDAR).

REFERENCES:

1. Mullen, L.; Lee, R. and Nash, J. "Digital passband processing of wideband-modulated optical signals for enhanced underwater imaging." Applied Optics, vol. 55, no. 31, 2016, pp. C18-C24.
2. Mack, K.V.; Jemison, W.D.; Rumbaugh, L.K.; Illig, D.W. and Banavar, M.K. "Time-of-Flight (ToF) Cameras for Underwater Situational Awareness." Proceedings of OCEANS 2019 MTS/IEEE Seattle, 2019, pp. 1-5.
3. Kadambi, A.; Schiel, J. and Rasker, R. "Macroscopic Interferometry: Rethinking Depth Estimation with Frequency-Domain Time-of-Flight." Proceedings of 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Las Vegas, 2016.

KEYWORDS: LIDAR; laser imaging; underwater vision; time of flight camera; 3D camera; modulated laser; undersea weapon; underwater sensor