18Gb/s Optical IO: VCSEL Driver and TIA in 90nm CMOS

Abstract

An 18 Gb/s optical data rate is achieved with a commercial GaAs VCSEL by applying rising and falling edge pre-emphasis with a 90 nm CMOS driver. The pre-emphasis pulse shape can be digitally adjusted with time resolution less than one bit period. The TIA receiver has cross-coupled cascodes to increase the amplifier gain/bandwidth and operates at 12.5 Gb/s to 18 Gb/s depending on the input capacitance.