Data Recovery and Pulse Position Modulation with a Photon Number Resolving SNSPD

A version of this chapter is in preparation for submission to Optics Express.

Abstract

Superconducting Nanowire Single Photon Detectors have leading low-jitter performance, especially in the mid-infrared. They are useful for classical communication over high loss channels –such as across deep space– and for quantum communication for which signals are restricted to the few-photon level. For classical communication, high photon information efficiency communication may be achieved with Pulse Position Modulation (PPM) whereby data is encoded in the arrival time of an optical pulse with respect to a clock. In the process of demonstrating PPM on a 20 GHz clock, we study the effects of Photon Number Resolution (PNR) in new low-jitter types of SNSPDs. These PNR effects complicate fixed-threshold triggering of RF pulses from the SNSPD, and corrupt arrival time measurements if not properly managed. We demonstrate methods for simultaneous arrival time and photon number measurement which enables high clock rate PPM for space applications as well as high rate quantum communication and computing applications that benefit from photon number resolution.