42-Gbps/ch x 4 ch Simultaneous Error-Free Operation with Low-Power Transmitter Flip-Chip-Bonded 1.3-μm LD-Array-on-Si

Gbps/ch NRZ PRBS-31 x 4 ch simultaneous error-free BtoB operation was achieved with a 4-ch transmitter used LD drivers with EO-bandwidth-improvement functions, yielding an LD bandwidth increase of 60% and power efficiency of $2.06 \mathrm{~mW} / \mathrm{Gbps}$.