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Superconducting Materials and Devices

Above: A 12-pixel fiber-coupled tungsten silicide SNSPD array is prepared for measurement on a subkelvin refrigerator.

Superconducting Nanowire Single-Photon Detectors Study Marks Three Milestones

The Lunar Laser Communication Demonstration (LLCD), NASA’s first high-rate, two-way, space laser communication technology demonstration has successfully completed its mission from orbit around the Moon on April 18, 2014. In collaboration with JPL’s optical communication group, a ground receiver for LLCD based on an MDL-fabricated 12-pixel SNSPD array was developed. This receiver was fielded on the Optical Communications Telescope Laboratory (OCTL) at JPL’s Table Mountain Facility, and used to successfully downlink error-free data from lunar orbit at 79 megabits per second.

The free-space optical coupling is adjusted for a 64-element SNSPD module for NASA’s Deep Space Optical Communication project. MDL has fabricated the largest active-area SNSPD array to date.

In addition, two different versions of free-space coupled SNSPD arrays with photon collection areas 8 times larger than the previous state of the art arrays were demonstrated with useful optical efficiency. The arrays were used for proof-of-concept advanced communication experiments under NASA’s Deep Space Optical Communication project and DARPA’s Information in a Photon program.

MDL’s tungsten silicide SNSPDs have demonstrated record-breaking efficiency (> 90%) in the infrared, with 150 ps timing jitter, 40 ns reset time, and subhertz intrinsic dark counts. They may be useful for a variety of future applications such as lidar, quantum communications, and high-time-resolution astrophysics.

 

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