Propagation of Optical Signals Encrypted with Spectral Phase Encoding and Signal/Polarisation Shuffling

Non-intrusive tapping and other threats have underscored the necessity for enhanced security mechanisms in transparent optical networks (TONs). In this work, we explore the application of both intra- and inter-signal cryptography techniques to secure TON signals. The intra-signal approach utilizes spectral phase encoding, while the inter-signal technique relies on shuffling the samples among different signals, including the X - and Y polarisation components of each signal. Computer simulation results suggest that encrypted $448 \mathrm{~Gb} / \mathrm{s}$ dual polarisation (DP) 16-quadrature amplitude modulation (QAM) signals may be properly recovered after $\sim 700 \mathrm{~km}$ of standard single-mode fiber propagation.