Quantum Photon Detector for Operation in the Telecom C Band

Emerging technologies for achieving secure communication through the use of quantum photonic systems necessarily require the ability to detect single photons. At the same time, existing telecommunications infrastructure requires practical, high-speed components operating in the C wavelength band. There is no present-day technology capable of combining these requirements to perform practical, high-speed detection of single C band photons, but such a technology must be developed in pursuit of the next generation of fast, secure quantum telecommunications networks. A review of present-day technologies for single photon detection reveals several possible paths forward to achieving practical, high-speed detection of single C-band photons. The objective of this program is to investigate improvements to the performance of the most promising of these existing single photon detector technologies by re-implementing the approach in a purpose-driven alternative semiconductor material system. Advantageous properties of alternative semiconductor materials previously unexplored for this purpose will bridge the performance gap between present-day technology and next-generation requirements. During Phase I of this program, Amethyst will design and fabricate novel C band single-photon detectors based on the semiconductor materials GaSb and AlGaSb, as well as analogous conventional detectors based on the materials InGaAs and InP. Amethyst will perform electro-optical characterization of devices implemented in both material systems and will demonstrate the superior performance of the novel GaSb/AlGaSb approach. Phase II of the program will involve more complicated characterization of the performance of single photon detector devices, including direct probing of the fundamental material characteristics responsible for fundamental performance limits. The Phase II program will culminate in the demonstration of a complete C band single-photon receiver based on the novel single-photon detector structure developed here and known and readily available C band electronics. Development of an inexpensive, high-performance, single-photon detector based in III-V semiconductor materials lattice matched to GaSb substrates and operating in the telecom C band will help bring quantum technology out of the laboratory and into the marketplace. The single-photon detector developed via this DoE SBIR program will be a building block for future quantum networks that operate over long-haul optical fibers, having a variety of commercial and scientific applications. A high-speed, C band single-photon detector will allow for further development of quantum key distribution for improved cryptographic protocols. Eventually, the technology could be applied directly to other consumer data privacy needs to ensure safe transfer of protected information. Additional applications include quantum cryptography for secure communications, free space communications, and quantum networks to link quantum computers.