Probabilistically shaped CAP based on group-level labeling and graphene-shaped constellation

This paper presents a probabilistically shaped (PS) carrier-less amplitude phase (CAP) modulation scheme enabled by group-level labeling and graphene-shaped constellation. A 9.8 Gb/s graphene-shaped PS 32-to-24 CAP transmission experiment over a 25-km standard single-mode fiber is successfully demonstrated. The results validates that our scheme can achieve a 1.8 dB receiver sensitivity improvement compared with the uniform CAP-32 signal due to the probabilistic and geometric shaping gain.