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A microwave reflection control technique that improves the performance of electroabsorption modulators (EAMs) is presented. The technique exploits the superposition of incident and reflected electrical signals as a modulation signal to enhance the modulation signal voltage applied to EAMs and therefore differs from conventional impedance matching techniques in terms of operating principle. A nearly flat electrical-to-optical frequency response up to 50 GHz and significant improvement in eye openings at 40 Gbit/s have been achieved with the technique. The effects of the technique are demonstrated through both experimental and computational investigations. [ABSTRACT FROM PUBLISHER]

We clarified experimentally that an EA-DFB laser in which the EAM and DFB parts are coupled with a passive waveguide provides a large bandwidth, even when a large reverse bias is applied to the EAM. This allows the chip to operate in a negative-chirp condition. We fabricated an EA-DFB module terminated with a 50 Omega resistor through a dc-block capacitor to suppress the increase in dc current as the reverse bias increases. A module equipped with our new EA-DFB chip successfully transmitted data over a distance of 3 km at a rate of 40 Gbit/s and at a driving voltage as low as 2 V. [ABSTRACT FROM PUBLISHER]

A high-performance 1.3 µm InGaAlAs electroabsorption modulator integrated with a DFB laser for the metro-area 100 Gbit/s Ethernet system (100GBASE-LR4 and -ER4) has been developed. 40 km transmission under 25 Gbit/s operation on singlemode fibre that is required for 100GBASE-ER4 application at 40°C is demonstrated for the first time. [ABSTRACT FROM AUTHOR]

40 Gbit/s electroabsorption modulators with an RF extinction ratio of 10 dB and driven by a peak-to-peak voltage as low as 1.1 V have been successfully fabricated. This low driving voltage is achieved by employing strain-compensated InGaAlAs/InAlAs multi-quantum-well layers with very good extinction characteristics and by optimising the number of wells and electroabsorption length. [ABSTRACT FROM AUTHOR]