Forward-Biased Silicon Phase Shifter Modelling for Electronic-Photonic Co-Simulation and Validation in a 250 nm EPIC BiCMOS Technology

A physical model of a forward biased silicon phase shifter (FB-PS) in a 250 nm electronic-photonic integrated circuit (EPIC) BiCMOS technology was developed and fitted to measurement results. The model is implemented via VerilogA and SPICE to allow usage in all standard EDA software tools, enabling reliable simulations of electrooptical transmitter systems with FB-PSs. Physical effects inside the phase shifter (PS) are modelled individually by VerilogA/SPICE building blocks, allowing independent parametric modelling and fitting, as well as investigation of internal charges, currents, voltages and electromagnetic field parameters. Therefore, the presented FB-PS modelling is universally applicable and adoptable to FB-PSs in different technologies. The modelled FB-PS exhibits high efficiency, enabling very compact Mach-Zehnder modulators (MZM) with short PS length. All considered physical effects, measurement setups, model parameters, VerilogA implementations, and a bandwidth extension technique are presented. Validation of the model is done by means of electrooptical bandwidth measurements and non-return-to-zero signal generation experiments.