A time-delay signature elimination and broadband electro-optic chaotic system with enhanced nonlinearity by deep learning

Abstract

In this paper, a novel electro-optic chaotic system with enhanced nonlinearity by deep learning (ENDL) is proposed to achieve time-delay signature (TDS) elimination. A long-short term memory network (LSTM) is trained by a specially designed loss function to enhance the nonlinear effect that can hide the TDS of the system. For the first time, the trained deep learning module is put into a single feedback loop to participate in chaos generation. Simulation results show that the ENDL system can eliminate TDS and increase the bandwidth to more than 31GHz when the feedback intensity is very low (α = 4V). Moreover, the complexity of the chaotic output can be improved with permutation entropy (PE) reaching 0.9941. The synchronization result shows that the ENDL system has high sensitivity to TDS but has low sensitivity to the feedback intensity, thus the system has both high security and high robustness. This system has an uncomplicated synchronization structure and high flexibility, and it opens up a new direction for high-quality chaos generation.

Physical Layer Encryption for CO-OFDM Systems Enabled by Camera Projection Scrambler

“…Various physical layer encryption methods, such as quantum key distribution (QKD) [7], optical steganography [8], optical code division multiple access (OCDMA) [9], hardware chaos encryption [10][11][12][13], and digital chaos encryption [14][15][16][17][18][19][20][21][22][23][24], etc., have all made significant contributions to securing data. Zhang et al used an implementation of high-speed QKD in an SiP QKD encoder using a pass-block architecture and a dedicated SiP decoder based on the polarization-based decoy state Bennett-Brassard 1984 protocol [7].…”

“…Lu et al used an electro-optical chaotic system with phase modules for time delay signature elimination through deep learning to enhance nonlinearity. Long short-term memory (LSTM) networks are trained with specially designed loss functions to enhance the nonlinear effects [10]. Digital chaotic encryption with digital signal processing (DSP) technology saves a lot of components and is easy to operate, and many researchers have invested in the work.…”

Electro-optical chaotic communication system based on additional chaotic phase-shift with time-delay signature concealment

“…For the above reasons, electro-optical chaotic systems have been extensively studied and analyzed by scholars in corresponding fields in recent years 9 – 11 …”

“…For the above reasons, electro-optical chaotic systems have been extensively studied and analyzed by scholars in corresponding fields in recent years. [9][10][11] The chaotic signal of the electro-optical chaotic feedback system is generated based on the delay differential equation. The existence of the time-delay in the feedback loop increases the complexity and dimension of the chaos.…”

Time-Delay Signature Concealment in a Security-Enhanced Optical System With Dual-Loop Electro-Optic Self- Feedback Phase Encryption

“…In 2022, Cheng et al reported the conception of increasing the nonlinear dimensionality of the chaotic system in the transmitter while decreasing the dimensionality of the transmitted signal [24]. More recently, TDS elimination with enhanced nonlinearity by deep learning has been inventively conceived and demonstrated [25].…”