Highly Security 7-Core 16 WDM OCDM Transmission System Based on Time-Domain Spectral Dynamic Disturbance

This paper proposes an encryption scheme based on the dynamic disturbance of time-domain spectra for orthogonal chirp division multiplexing (OCDM) and implements wavelength division multiplexed (WDM) transmission in 7-core fiber. The encryption of the signal is realized entirely in the digital domain, and we introduce the dispersion perturbation in the digital signal processing to realize the dynamic disturbance of the time-domain spectral waveform. The three-dimensional Lorenz chaotic model generates the encryption factors to perturb the orthogonal chirp subcarriers, chirp constellations, and dispersion values. Data of 16 channels is multiplexed via WDM and the 1.12 Tb/s encrypted signal is successfully transmitted over a 2km 7-core fiber. The experimental findings indicate that the proposed secure OCDM-WDM scheme exhibits compatibility across various modulation formats and transmission rates, achieving a key space of 1 × 10 ⁹⁰ . Meanwhile, the encrypted signals get gains of 0.55, 0.61 and 0.42 dB compared to the unencrypted under the modulation formats of QPSK, 8QAM and 16QAM respectively, demonstrate the significant potential applications of the proposed scheme in the realm of future optical communications.