25-Gbaud PAM4 and 1300nm directly modulated laser diode using low parasitic electrodes for long-distance transmission

A new high-speed 1300nm directly modulated DFB laser with high power has been demonstrated. With low parasitic capacitance of coplanar electrodes, 25mW has been obtained in a long waveguide, while maintaining high-speed performance. 50Gb/s PAM-4 modulation over 35km transmission without amplification has been realized with low degradation.