Ultrafast superconducting single-photon detector with a reduced active area coupled to a tapered lensed single-mode fiber

Abstract

This paper presents an ultrafast niobium nitride (NbN) superconducting single-photon detector (SSPD) with an active area of 3×3 μ m 2 that offers better timing performance metrics than the previous SSPD with an active area of 7×7 μ m 2 . The improved SSPD demonstrates a record timing jitter ( ), an ultrashort recovery time ( ), an extremely low dark count rate, and a high detection efficiency in a wide spectral range from visible part to near infrared. The record parameters were obtained due to the development of a new technique providing effective optical coupling between a detector with a reduced active area and a standard single-mode telecommunication fiber. The advantages of the new approach are experimentally confirmed by taking electro-optical measurements.