A 40Gb/s PAM4 Optical DAC Silicon Microring Resonator Modulator Transmitter
Additional Document Info
2017 IEEE. PAM4 modulation is currently being implemented in high-speed wireline communication standards in order to increase bandwidth density. This paper presents a transmitter which utilizes a low-area silicon microring resonator modulator with two separate phase shifter segments to realize high-speed PAM4 modulation with an optical DAC approach. The optical DAC is designed with an optimized MSB/LSB segment size ratio of 1.9:1 to generate a uniform four level output with independent MSB/LSB two-level NRZ drivers. Two differential high-swing segmented pulsed-cascode output stages drive the MSB/LSB segments with independent edge-rate and level controls that compensate for output level spacing and eye skew. The hybrid integrated prototype, with the optical DAC microring modulator fabricated in a 130nm silicon photonic process and the transmitter circuitry fabricated in a GP 65nm CMOS process, achieves 40Gb/s operation at 4.38mW/Gb/s when driving each differential terminal of the segmented depletion-mode microring modulator with 4.4Vppd swing.
name of conference
2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS)