239.3-Gbit/s net rate PAM-4 transmission using directly modulated membrane lasers on high-thermal-conductivity SiC

We present a directly modulated membrane laser on high-thermal-conductivity SiC exhibiting >100-GHz bandwidth. A ∼40-GHz relaxation oscillation frequency, owing to low thermal resistance and high optical confinement, and a ∼95-GHz photonphoton resonance are achieved. Net 239.3-Gbit/s PAM-4 transmission over 2-km standard single-mode fibre is demonstrated.