Ongoing R&D into quantum computing, quantum communications, and quantum networking solutions requires optical detectors that can detect a single photon with high efficiency. For many experiments, it is critical to know the precise detection efficiency of these detectors. Calibrating these detectors is currently a challenge as these detector are often large, complex, and fragile and must be shipped to a calibration facility for measurement. We propose an alternate method of detector calibration that permits on-site detector calibration using a small, rugged quantum bi-photon source. These bi-photon sources can be used with a calibration method previously reported and demonstrated by NIST (the Klyshko method). As part of our proposed Phase I project, a proof-of-principle demonstration of the Klyshko calibration method will be implemented using a commercial-off-the-shelf (COTS) bi-photon source offered by Qubitekk. The calibration accuracy achievable with this non-optimized COTS source will be demonstrated and documented. This COTS source design will then serve as the starting point for an optimized, enhanced stability, prototype bi-photon source for on-site detector calibration. The performance improvements of this prototype source design will be estimated through optical modeling and experimental measurements and compared against the COTS source specs and testing data. The suitability of the prototype for various environments (both space-based and terrestrial) will be evaluated through modeling and comparison with prior testing data. The ability of the prototype source to characterize SPD efficiency across a broad wavelength spectrum will be evaluated and any spectral gaps or range limitations identified. The design and anticipated performance improvements related to this prototype, optimized bi-photon source will be detailed in the projectâs final report and its construction and testing proposed as part of any follow-on Phase II effort. Potential NASA Applications (Limit 1500 characters, approximately 150 words): The proposed technology has applications related to the NASA mission, including secure satellite communication networks, deep space laser communications (using terrestrial single photon counting arrays), quantum sensors for atmospheric measurements, and a large number of applications enabled by quantum computers. The proposed technology is in direct response to NASA STTR solicitation and its request for quantum sources "needed for system calibration of single-photon counting detectors and energy-resolving single-photon detector arrays." Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): The proposed technology has wide application across the emerging quantum technology markets. These markets - which consist of products related to quantum computing, quantum communications, and quantum sensing solutions â have seen rapid growth over the past decade. The largest of these non-NASA applications include cybersecurity for critical infrastructure and quantum computing for data mining. Duration
