Experimental demonstration of a 4,294,967,296-QAM-based Y-00 quantum stream cipher template carrying 160-Gb/s 16-QAM signals.

Xi Chen,Argishti Melikyan,Ken Tanizawa,Po Dong,Kentaro Kato,K W Kim,Junho Cho,Peter Winzer,Fumio Futami

doi:10.1364/oe.405390

Abstract

We demonstrate a 4,294,967,296-quadrature amplitude modulation (QAM) based Y-00 quantum stream cipher system carrying a 160-Gb/s 16-QAM signal transmitted over 320-km SSMF. The ultra-dense QAM cipher template is realized by an integrated two-segment silicon photonics I/Q modulator.

Highlights

Fiber-optic transmission systems are susceptible to eavesdropping and require encryption for sensitive data
We show that we can generate a 4,294,967,296 (=232) quadrature amplitude modulation (QAM) based Y-00 ciphertext that carries 22-GBaud 16-QAM information at 160-Gb/s physical-layer secure net rate with 320-km standard single mode fiber (SSMF) transmission
With the two-segment I/Q modulator, we demonstrate the transmission of a 22-GBaud 16QAM signal encrypted into a 4,294,967,296-QAM Y-00 quantum stream ciphertext

Summary

Introduction

Fiber-optic transmission systems are susceptible to eavesdropping and require encryption for sensitive data. OTP encryption requires the key to have the same length as the data/plaintext, which limits the data rate to the key distribution rate. The Advanced Encryption Standard (AES) is a practically secure scheme applied in application layer. The Y-00 quantum stream cipher [3,6,7,8] is one of the physical layer encryption schemes that uses inevitable quantum noise/shot noise at detection to mask the information. The scheme relies on an encryption algorithm to convert a lower-order quadrature amplitude modulation (QAM) original constellation to an ultra-dense higher-order QAM constellation, which together with fundamental shot noise in photodetection makes recovery of the information impossible without the key. The higher the order of the ultra-dense modulation is chosen that the original data is converted to, the more security the system can provide. The largest demonstrated encrypted QAM size is 1,048,576 (=220) QAM with low-speed 10-bit DACs at a symbol rate of 5 GBaud and line rate of 70 Gb/s [9]

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