N232-098 TITLE: Photodetector and Optical Subassembly for Digital Fiber Optic Receiver

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Sustainment

OBJECTIVE: Develop and package uncooled photodetectors and optical subassemblies for military digital optical communications applications that can operate in air platforms at 10, 25, 40, 50, and 100 Gbps using binary, non-return-to-zero, on-off keyed data modulation techniques in fiber optic receivers.

DESCRIPTION: Current airborne military (mil-aero) core avionics, electro-optic (EO), communications, and electronic warfare systems require ever-increasing bandwidths while simultaneously demanding reductions in space, weight, and power (SWaP). The effectiveness of these systems hinges on optical communication components that realize high per-lane throughput, low latency, large link budget, and are compatible with the harsh avionic environment.

As digital avionics fiber-optic transmitter transmission rates increase from 10�100 Gbps, a new fiber-optic receiver will be required. A key enabling component in the fiber-optic receiver is a high-sensitivity and saturation photodetector that is compatible with 50 �m core multimode optical fiber, and various connectorized and fiber-pigtailed subassembly designs for both single-wavelength multimode fiber receivers and wavelength de-multiplexed and receiver arrays. The photodetectors should enable 15 dB receiver loss budget performance at 10 Gbps, 25 Gbps, 50 Gbps, and 100 Gbps. Photodetectors should be compatible with shortwave wavelength division multiplexing (SWDM) (844�1000 nm) and coarse wavelength division multiplexing (CWDM) (1271�1331) wavelength band ranges. Individual photodetector designs are acceptable for each wavelength band. The photodetector optical subassemblies should be compatible with 4 X 10 Gbps, 2 X 20 Gbps, 4 X 25 Gbps, 1 X 50 Gbps, 2 X 50 Gbps, and 1 X 100 Gbps transmission speeds. The optical subassemblies should be compatible with 50 �m core OM4 multimode optical fiber inputs, and 10 Gbps, 25 Gbps, 40 Gbps, 50 Gbps, and 100 Gbps receiver electronic circuits. The optical subassemblies are expected to operate over a -40� to +95� Centigrade temperature range.

PHASE I: Develop a design concept for photodetectors and their optical subassemblies for military digital fiber-optic communication applications. Demonstrate the feasibility of the photodetector design, showing a path toward meeting Phase II goals. Show optical subassembly design compatibility with fiber-optic inputs and receiver circuits. Demonstrate the feasibility of the concept to meet the described parameters listed in the Description through modeling, simulation, and analysis. The Phase I Option, if exercised, will include initial design specifications and capabilities description to build prototype solutions in Phase II. Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Design and develop prototype photodetectors optimized using results from Phase I. Build and test the photodetectors and photodetector optical subassemblies and deliver to the Navy. If necessary, perform root-cause analysis and remediate photodetector and optical subassembly failures.

PHASE III DUAL USE APPLICATIONS: Transfer the photodetector and optical subassembly design to a high-speed digital fiber optic receiver supplier. Photodetector and optical subassembly technology could be used in commercial data center and/or internet provider installations.

REFERENCES:

1. Binh, L N. (2017). Advanced digital optical communications (2nd ed.). CRC Press. https://www.routledge.com/Advanced-Digital-Optical-Communications/Binh/p/book/9781138749542
2. Verbist, J., Verplaetse, M., Srivinasan, S. A., De Heyn, P., De Keulenaer, T., Pierco, R., Vaernewyck, R., Absil, P., Torfs, G., Yin, X., Roelkens, G., Van Campenhout, J., & Bauwelinck, J. (2017, March). First real-time 100-Gb/s NRZ-OOK transmission over 2 km with a silicon photonic electro-absorption modulator. In Optical Fiber Communication Conference (pp. Th5C-4). Optical Society of America. https://opg.optica.org/abstract.cfm?URI=OFC-2017-Th5C.4
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4. AS-3 Fiber Optics and Applied Photonics Committee. (2018, January). AS5750A Loss budget specification for fiber optic links. SAE. https://saemobilus.sae.org/content/as5750a
5. The MIL-STD-810 Working Group. (2008, October). MIL-STD-810G: Department of Defense test method standard: Environmental engineering considerations and laboratory tests. Department of Defense. http://everyspec.com/MIL-STD/MIL-STD-0800-0899/MIL-STD-810G_12306/
6. AS-3 Fiber Optics and Applied Photonics Committee. (2018, August). Aerospace Standard ARP6318: Verification of discrete and packaged photonic device technology readiness. SAE International. https://saemobilus.sae.org/content/arp6318
7. Wang, B., Huang, Z., Sorin, W. V., Zeng, X., Liang, D., Fiorentino, M., & Beausoleil, R. G. (2019). A low-voltage Si-Ge avalanche photodiode for high-speed and energy efficient silicon photonic links. Journal of Lightwave Technology, 38(12), 3156-3163. https://doi.org/10.1109/JLT.2019.2963292
8. Defense Logistics Agency Land and Maritime. (2016). MIL-STD-883K: Department of Defense test method standard: Microcircuits. Department of Defense. http://everyspec.com/MIL-STD/MIL-STD-0800-0899/MIL-STD-883K_54326/

KEYWORDS: Photodetector; fiber optics; communications, digital; receiver; optical subassembly

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