100 Gb/s (4×28 Gb/s) transmission in C-band by a directly modulated integrated transmitter and DSP-free coherent detection

We report C-band 100 Gb/s transmission (4?28 Gb/s) up to 6.5 km of standard single mode fiber exploiting an InP monolithically integrated WDM transmitter made by an array of four directly modulated DFB lasers on a 100?GHz spaced grid having a 3-dB bandwidth in excess of 20?GHz. To overcome the conventional chirp related chromatic dispersion limitation, we use the compact integrated transmitter in combination with a simplified DSP-free coherent detection scheme suitable for low cost, low power applications.