Mach–Zehnder modulator integrated with a gain-coupledDFB laser for 10 Gbit/s, 100 km NDSF transmission at 1.55 µm

The first monolithic integration of an interferometric modulator with a gain-coupled distributed-feedback laser is reported. The integrated MZ/DFB is fabricated by butt-coupling in order to minimise design constraints on the MZ and DFB active regions. 10 Gbit/s transmission over 100 km of NDSF at λ = 1.55 µm is achieved with a receiver penalty of <1 dB. ~90% of the integrated lasers emit in a single longitudinal mode.