A Compact Verilog-A Model of Silicon Carrier-Injection Ring Modulators for Optical Interconnect Transceiver Circuit Design

Abstract

Optical interconnect system efficiency is dependent on the ability to optimize the transceiver circuitry for low-power and high-bandwidth operation, motivating co-simulation environments with compact optical device simulation models. This paper presents a compact Verilog-A silicon carrier-injection ring modulator model, which accurately captures both non-linear electrical and optical dynamics. The device's electrical behavior is described by a p-i-n diode SPICE model, while the optical response is captured with a dynamic ring resonator model, which considers the ring's cumulative phase shift. Experimental verification of the model is performed both at 8 Gb/s with symmetric drive signals to study the impact of pre-emphasis pulse duration, pulse depth, and dc bias, and at 9 Gb/s with a 65 nm CMOS driver capable of asymmetric pre-emphasis pulse duration. The potential for 15 Gb/s operation is shown by utilizing the presented model for optimization of the asymmetric pre-emphasis signal waveform.