40 Gbit/s directly modulated passive feedback laser

High speed directly modulated lasers are key devices for compact, low cost transmitters. In this paper we describe the mechanism of modulation bandwidth enhancement by passive feedback sections and the characteristics of accordingly fabricated 1.55 mum InGaAsP/InP lasers. The system performance at 40 Gbit/s is analysed, including VSR transmission and BER measurements, and the potential for chirp tuning is shown.