10-Gbit/s transmission using an integrated electroabsorption-modulator/DFB laser grown by selective-area epitaxy

Optical transmitters with monolithically integrated electroabsorption-modulator/DFB lasers (EMLs) are expected to be key components in future lightwave transmission systems. The low chirp of these devices makes them well suited for long-haul (500 km) 2.5-Gbit/s transmission systems that make use of existing standard fiber and erbium-doped fiber amplifiers (EDFAs).1 Recently, several groups have also reported transmission at 10 Gbit/s over 50 km of standard fiber,2 which is the theoretical dispersion limit, as well as over longer spans by using dispersion-shifted fiber3,4 or nonlinear dispersion compensation.2 However, many of these devices have a butt-joined waveguide structure and/or use polyimide dielectrics to reduce the parasitic capacitance of the modulator,2,3 both of which are serious concerns for manufacturability and long-term reliability.