Optimized 25Gb/s Electroabsorption Modulated Tunable Lasers for O-band DWDM Systems

We propose and experimentally demonstrate an O-band electroabsorption modulated tunable in-series DFB laser array (EMTL). Four lasers with 400-GHz spacing in the laser array are placed in series to avoid the usage of an optical combiner and the additional power loss. The reconstruction-equivalent-chirp technique is used to simplify the grating fabrication and precisely control the grating phase. A semiconductor optical amplifier is integrated in front of the electroabsorption modulator (EAM) to amplify the output power. As a result, we realized 16 channels with 100 GHz spacing with the SMSRs of above 40 dB. The modulation bandwidth of the EAM is above 20 GHz, and 25Gb/s data per wavelength is obtained. The proposed EMTL shows the potential application as a compact and low-cost light source for DWDM systems, such as the next-generation fronthaul networks and passive optical networks in O-band.