NIR Single Photon Detectors with Up-Conversion Technology and its Applications in Quantum Communication Systems

Abstract

The performance of any quantum communication system is limited by its transmission loss and detection efficiency, both of which must be balanced for optimal overall system performance. For current fiber-optic based systems, the transmission loss is small in the near infrared (NIR) range, and many fiber-based communication systems and devices tend to use this wavelength range. Therefore, the 1310 nm and 1550 nm bands, both of which are in the NIR range, have become mainstream in the telecom industry. However, the most efficient and low cost single photon detectors, such as silicon based avalanche photodiodes (APD), do not work in the NIR wavelength range. Bridging this gap is, of course, essential for an optimal quantum communication system. In current systems, the preferred types of single photon detectors include photocathodebased detectors, APD-based detectors and superconducting-based detectors. Photocathodebased detectors use an InGaAs/InP photomultiplier tube (PMT) or an InGaAs Microchannel plate (MCP) for single photon detection in the NIR range. APD-based detectors, on the other hand, may only use InGaAs/InP APDs when detecting NIR single photons. Almost all superconducting-based detectors work in the NIR and can be described by two main types, including the Transition Edge Sensor (TES) and Superconducting Single-Photon Detectors (SSPD). In addition to these mainstream detectors, single photon detection at NIR can be achieved using a technique known as frequency up-conversion. We discuss this alternative technique in detail in this chapter.