DFB lasers with integrated electroabsorption modulator

We present high-performance 1550nm DFB lasers with butt-coupled, bulk type integrated electroabsorption modulators of good manufacturability and reliability. Key issues in device design are reviewed and the strong influence of the exact detuning between lasing wavelength and modulator bandgap is demonstrated. Fibre-coupled output powers as large as 6 dBm and attenuation efficiencies as high as 12 dB V -1 are obtained. Butterfly-packaged devices show only 1 dB penalty for l0 Gbits -1 NRZ transmission over 50-km standard single-mode fibre (SMF) without the use of an optical amplifier. With an optical booster amplifier, self-phase-modulation in the fibre is exploited and repeaterless 10 Gbits -1 transmission is possible over 150-km standard SMF.