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 S
₁₁
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.