High-performance eight-channel system with fractal superconducting nanowire single-photon detectors

Authors:
raw_author_name: Zifan Hao
raw_affiliation_string: Key Laboratory of Optoelectronic Information Science and Technology, Ministry of Education, Tianjin, 300072, China; School of Precision Instrument and Optoelectronic Engineering, Tianjin University, Tianjin, 300072, China
raw_author_name: Kai Zou
raw_affiliation_string: Key Laboratory of Optoelectronic Information Science and Technology, Ministry of Education, Tianjin, 300072, China; School of Precision Instrument and Optoelectronic Engineering, Tianjin University, Tianjin, 300072, China
raw_author_name: Fangyuan Li
raw_affiliation_string: State Key Laboratory of Modern Optical Instrumentation, College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 300072, China
raw_author_name: Yongheng Huo
raw_affiliation_string: Hefei National Research Center for Physical Sciences at the Microscale and School of Physical Sciences, University of Science and Technology of China, Hefei, 230026, China
raw_author_name: Adrian Iovan
raw_affiliation_string: Department of Applied Physics, Royal Institute of Technology (KTH), SE-106 91 Stockholm, Sweden
raw_author_name: Val Zwiller
raw_affiliation_string: Department of Applied Physics, Royal Institute of Technology (KTH), SE-106 91 Stockholm, Sweden
raw_author_name: Xiaolong Hu
raw_affiliation_string: Key Laboratory of Optoelectronic Information Science and Technology, Ministry of Education, Tianjin, 300072, China; School of Precision Instrument and Optoelectronic Engineering, Tianjin University, Tianjin, 300072, China

Abstract: Superconducting nanowire single-photon detectors (SNSPDs) have become a mainstream photon-counting technology that has been used in various applications. So far, most multi-channel SNSPD systems, either reported in literature or been commercially available, are polarization sensitive, that is, the system detection efficiency (SDE) of each channel is dependent on the state of polarization of the to-be-detected photons. Here, we report on an eight-channel system with fractal superconducting nanowire single-photon detectors working in the wavelength range of 930-940 nm that all feature low polarization sensitivity. In a close-cycled Gifford-McMahon cryocooler system with the base temperature of 2.2 K, we install and compare the performance of two types of devices: (1) SNSPD, composed of a single, continuous nanowire, and (2) superconducting nanowire avalanche photodetector (SNAP), composed of 16 cascaded units of two nanowires electrically connected in parallel. The highest system detection efficiency (SDE) among the eight channels reaches 96−5+4%, with polarization sensitivity of 1.02 and dark-count rate of 13 counts per second. The average SDE for eight channels for all states of polarization is estimated to be 90 ± 5%. We conclude that both the SNSPDs and the SNAPs can reach saturated, high SDE at the wavelength of interest, and the SNSPDs show lower dark- (false-) count rates while the SNAPs show better properties in the time domain. Using this system, we showcase the measurements of the second-order photon-correlation functions of light emission from a single-photon source based on a semiconductor quantum dot and from a pulsed laser. We believe that our work provides new choices of systems with single-photon detectors combining the merits of high SDE, low polarization sensitivity, and low noise that can be tailored for different applications.