High extinction ratio operation at 40-Gb/s direct modulation in 1.3-/spl mu/m InGaAlAs-MQW RWG DFB lasers

Direct modulation of 1.3-mum InGaAlAs DFB RWG lasers at 40 Gb/s is experimentally demonstrated. This laser achieves a record extinction ratio of 5 dB under 40-Gb/s modulation. Moreover, it can provide 40-Gb/s modulated transmission over 2 km