A 10 Gb/s, 6 V p-p , Digitally Controlled, Differential Distributed Amplifier MZM Driver

Abstract

A 10 Gb/s, digitally controlled, differential distributed amplifier (DA) optical modulator driver is implemented in 0.18 μm SiGe-BiCMOS technology. The 2.87 mm 2 prototype integrates clock phase shifters, digital latches, limiting amplifiers, broadband n+/n-well back termination resistors and a substrate-shielded output line on chip. It produces 6 V p-p differential output swing across 50 Ω loads. The output edge speed is trimmable, with 20-80% rise/fall times ranging from <; 15 ps to 50 ps at 10 Gb/s. Minimum sensitivity of the ECL-compatible inputs is 65 mVp-p at 10 Gb/s single-ended, with negligible additive jitter. Measured output return loss is better than 10 dB below 35 GHz, sufficient to drive an external push-pull Mach-Zehnder optical modulator. Total power consumption is 2.13 W operating from -5.2 V and 5 V supplies. The fully-digital input interface supports scalability in the number of DA stages, output swing and to multiple output channels.