An SNSPD-based detector system for NASA's Deep Space Optical Communications project

TL;DR

This paper presents a superconducting nanowire single-photon detector array designed for NASA's deep space optical communication, achieving high efficiency, low false counts, and fast response suitable for space applications.

Contribution

The development of a 64-pixel SNSPD array with integrated optics and electronics optimized for deep space optical communication at Palomar Observatory.

Findings

Peak detection efficiency of 76% at 1550 nm

Background-limited false count rate of 3.7 kcps

Timing jitter less than 120 ps FWHM

Abstract

We report on a free-space-coupled superconducting nanowire single-photon detector array developed for NASA's Deep Space Optical Communications project (DSOC). The array serves as the downlink detector for DSOC's primary ground receiver terminal located at Palomar Observatory's 200-inch Hale Telescope. The 64-pixel WSi array comprises four quadrants of 16 co-wound pixels covering a 320 micron diameter active area and embedded in an optical stack. The detector system also includes cryogenic optics for filtering and focusing the downlink signal and electronics for biasing the array and amplifying the output pulses. The detector system exhibits a peak system detection efficiency of 76% at 1550 nm, a background-limited false count rate as low as 3.7 kcps across the array, timing jitter less than 120 ps FWHM, and a maximum count rate of ~ 1 Gcps.