20 Gbit/s Integrated Laser Diode Voltage Driver Using 0.3 μm Gate Length Quantum Well Transistors

An integrated laser diode voltage driver (LDVD) making use of enhancement/depletion AlGaAs/GaAs quantum well high electron mobility transistors (QW-HEMTs) with a gate length of 0.3 μm has been developed. Its large signal bandwidth was 12 GHz. Eye diagrams of the output signal at bit rates up to 8 Gbit/s showed an opening like that of the input signal. Increasing the bit rate of the input signal by means of a multiplexer, we can prove that the LDVD can operate at 20 Gbit/s. The maximum output current is over 90 mA; the maximum modulation voltage of 800 mV corresponds to 40 mA modulation current for a laser diode with 20 º dynamic resistance. The power consumption is less than 500 mW.