Transparent Transmission of a Secure Time Domain Spectral Phase Encoding/Decoding DPSK–OCDM Signal Over a DWDM Network

We propose and experimentally demonstrate a transparent optical-code-division multiplexing (OCDM) overlay public dense wavelength-division multiplexing (DWDM) network architecture enabled by a passive spectral notch filter for extracting and detecting a secure OCDM signal, which employs a time domain spectral phase encoding/decoding scheme that can simultaneously generate differential-phase-shift-keying (DPSK) data and optical code patterns using only a single phase modulator. The time domain encoded OCDM signal has been scrambled bit-by-bit by a prime hopping pattern and concealed in the public DWDM channels to significantly improve the OCDM channel security. The effect of optical code patterns, the channel number, and bandwidth of the spectral notch filters on the system performance has been theoretically simulated and experimentally validated. In the experiment, error-free transmission of a 2.5-Gb/s time domain spectral phase encoded DPSK-OCDM signal with three 8-chip, 20-Gchip/s optical codes and a scrambled code pattern in the transparent OCDM overlay two-channel 10-Gb/s DWDM network has been successfully demonstrated.