40-km single-mode-fiber transmission for 100-Gbit/s Ethernet system based on 25-Gbit/s 1.3-μm electroabsorption modulator integrated with distributed feedback laser

We have developed a 1.3-μm electroabsorption modulator integrated with a distributed feedback laser for medium- and long-distance 100-Gbit/s Ethernet. To ensure a sufficient extinction ratio in the 1.3-μm band, we used a tensile-strained quantum well absorbing layer made with InGaAlAs-based material, which has a larger conduction band offset than InGaAsP. The modulator was coupled to the laser by butt jointing to optimize the structure separately. The fabricated device packaged in a butterfly module has a small-signal 3-dB bandwidth of 33 GHz. With this module, we demonstrated 10- and 40-km transmission on a single-mode fiber at the modulation speed of 25 Gbit/s at 40°C.