10 Gbit/s series-connected voltage-balancing pulse driver with high-speed input buffer

A series-connected voltage-balancing pulse driver employing direct-coupled current switch architecture with a high-driving-capability input buffer and 0.1 μm InP HEMTs is presented. By connecting two HEMTs in series the driver can output 3.6 V_pp voltage swing. With the input buffer, the -3 dB limiting bandwidth of the driver increases from 11 to 30 GHz, and the rise and fall times decrease from 33 to 16 and from 37 to 16 ps, respectively. These short rise and fall times enable the driver to output clear 10 Gbit/s eye opening.