Gain-Coupled 4×56 Gb/s EML Array with Optimized Bonding-Wire Inductance

Gain-coupled 4 × 56 Gb/s electroabsorption modulated laser (EML) arrays are implemented by identical epitaxial layer (IEL) integration scheme. On-chip coplanar waveguide (CPW) electrodes are incorporated to reduce the parasitic capacitance and facilitate direct microwave probing of the device. Based on the circuit parameters extracted from the S11 data, the influence of bonding-wire inductance on the modulation performance of the EML is investigated. It is found that the modulation bandwidth can be enhanced by taking advantage of the bonding-wire induced resonance. Modulation bandwidth over 40 GHz as well as low microwave reflection has been experimentally confirmed by optimizing the bonding-wire inductance. Clear eye opening under 56 Gb/s nonreturn-to-zero (NRZ) modulation is demonstrated for the EML array with optimized bonding-wire length, and transmission through 10 km single-mode fiber (SMF) has been carried out.