Common-signal-induced synchronization in photonic integrated circuits and its application to secure key distribution

Abstract

We experimentally achieve common-signal-induced synchronization in two photonic integrated circuits with short external cavities driven by a constant-amplitude random-phase light. The degree of synchronization can be controlled by changing the optical feedback phase of the two photonic integrated circuits. The change in the optical feedback phase leads to a significant redistribution of the spectral energy of optical and RF spectra, which is a unique characteristic of PICs with the short external cavity. The matching of the RF and optical spectra is necessary to achieve synchronization between the two PICs, and stable synchronization can be obtained over an hour in the presence of optical feedback. We succeed in generating information-theoretic secure keys and achieving the final key generation rate of 184 kb/s using the PICs.

0.75 Gbit/s high-speed classical key distribution with mode-shift keying chaos synchronization of Fabry–Perot lasers

“…This transition time is determined by the rising time of the electrical codes from the low level to the high level which is measured as 1 ns. It is greatly shorter than that of optical-feedback semiconductor lasers with phase-shift keying, which was reported as about 68 ns 13 . The shortened transition time is beneficial to improving the rate of key distribution.…”

“…The key rate is more than 300 times higher than that of the key distribution with phase-shift keying chaos synchronization 13 thanks to that the transition time is greatly shortened. The final key generation ratio is 0.3139, and the retention ratio of dual-threshold quantization is calculated as 0.6301, which is slightly higher than that of integrated optical-feedback semiconductor lasers 13 because the lasers without feedback have stronger robustness of chaos synchronization. According to the entropy rate of 16 Gbit/s and the key generation ratio of 0.3139, one can expect a 5 Gbit/s key distribution rate.…”

“…Yoshimura et al further introduced random shift-keying modulation on the feedback phase as an additional layer of security 11 . A 182-kbit/s key distribution rate with 120-km fiber transmission was experimentally demonstrated by photonic-integrated optical-feedback lasers 13 . Subsequently, vertical-cavity surface-emitting laser under polarization-shift-keying optical injection 14 and analog–digital hybrid optical chaos source with phase-shift keying 15 were presented for key distribution.…”

Numerical study on dynamics-dependent synchronization in mutually-coupled lasers with asymmetric feedback

“…As monolithically integrated optical devices, Photonic Integrated Circuits (PICs) have been fabricated recently [16], which is suitable for the applications of random number generation [17][18][19][20][21] and secure key distribution [22]. The external cavity length plays an important role in laser dynamics with time-delayed optical feedback [23,24].…”

Real-Time 2.5-Gb/s Correlated Random Bit Generation Using Synchronized Chaos Induced by a Common Laser With Dispersive Feedback

“…characterized with wide bandwidth, large amplitude noise-like oscillation and synchronization possibility [2]. Such merits make them attractive for security-oriented applications, such as high-speed physical random bit generation [3][4][5][6][7][8][9][10][11], secure communication [12][13][14][15][16][17][18][19] and key distribution [20][21][22][23][24][25][26].…”