The paper presents a fiber-coupled single-photon detection system using superconducting nanowire single-photon detectors (SNSPDs) that achieve a system detection efficiency (SDE) of over 93% in the wavelength range of 1520-1610 nm. The system also features a low dark count rate of approximately 0.01 counts per second (cps), a timing jitter of about 150 picoseconds (FWHM), and a reset time of 40 nanoseconds. The SNSPDs are based on amorphous tungsten silicide (WSi) nanowires, which offer improved robustness and flexibility compared to traditional NbN nanowires. The system's performance is characterized over a wide range of temperatures, showing that the SDE remains high up to 2 K, and the dark count rate is dominated by blackbody radiation. The detector's polarization and wavelength dependence are also studied, demonstrating good performance across a broad spectral range. The paper concludes by discussing the potential for high fabrication yield and broad wavelength sensitivity, which could lead to advancements in mid-infrared detection and large-scale SNSPD arrays.The paper presents a fiber-coupled single-photon detection system using superconducting nanowire single-photon detectors (SNSPDs) that achieve a system detection efficiency (SDE) of over 93% in the wavelength range of 1520-1610 nm. The system also features a low dark count rate of approximately 0.01 counts per second (cps), a timing jitter of about 150 picoseconds (FWHM), and a reset time of 40 nanoseconds. The SNSPDs are based on amorphous tungsten silicide (WSi) nanowires, which offer improved robustness and flexibility compared to traditional NbN nanowires. The system's performance is characterized over a wide range of temperatures, showing that the SDE remains high up to 2 K, and the dark count rate is dominated by blackbody radiation. The detector's polarization and wavelength dependence are also studied, demonstrating good performance across a broad spectral range. The paper concludes by discussing the potential for high fabrication yield and broad wavelength sensitivity, which could lead to advancements in mid-infrared detection and large-scale SNSPD arrays.