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Фотонный рефлектометр во временной области на основе сверхпроводящего нанопроводникового однофотонного детектора и время-цифрового преобразователя
The Optical Time-Domain Reflectometer (OTDR) plays a key role in the diagnostics of fiber-optic networks and distributed fiber-optic sensing systems, enabling precise fault localization and performance optimization of long-haul communication links. This work presents a significant advancement in OTDR technology, achieved through the integration of a superconducting nanowire single-photon detector (SNSPD) and a field-programmable gate array (FPGA)-based time-to-digital converter (TDC). The SNSPD exhibits an efficiency of 63% at a wavelength of 1550 nm with a temporal jitter of 25 ps, while the FPGA-TDC provides a high temporal accuracy of 17.0 ± 1.3 ps at a high data acquisition rate. Experimental results demonstrate a dynamic range of 22.87 dB with a spatial resolution of 7.5 cm (at 25 km) and 1.6 m (at 100 km), confirming the system's high accuracy in determining fiber characteristics. This research lays the groundwork for the further development of real-time signal processing and automatic fault detection in fiber-optic networks, expanding their potential for applications in optical sensing.