LAUSR

This paper proposes an optimized 16-chip multi-level phase-shifted optical code division multiplexing (OCDM) en/decoder for 4-level pulse amplitude modulation (PAM-4) format by using an amplitude-shaping (AS) technique. The optimized en/decoder can efficiently suppress the crosstalk and the primary beat noise (PBN). The code detection performance for 4-OCDM PAM-4 becomes the lowest to our knowledge. The numerical bit error rate analysis and the back-to-back simulation are shown. We also successfully demonstrate by computer simulation a 100 Gbps/ $\lambda $ enabling by 12.5 Gbaud 4-OCDM PAM-4 transmission in O-band over $6\times 30$ km with in-line optical amplifiers.