Wavelength-tunable equivalent circuit models for SPICE-based photonic-electronic co-simulation

This paper introduces a SPICE-compatible photonic–electronic co-simulation framework based on the complex vector fitting (CVF) algorithm, developed for accurate representation of multi-wavelength behavior in linear and passive photonic integrated circuits (PICs). The proposed wavelength-tunable equivalent circuit models feature a fixed network topology, yet comprise components whose values are parameterized with respect to the optical carrier frequency. This enables both frequency- and time-domain simulations at arbitrary wavelengths, making the framework particularly suited for modeling multi-wavelength photonic systems. To support intricate co-simulation with electronic subsystems, a novel interface circuit is introduced, allowing seamless interconnection with third-party active and passive SPICE models. The capability of the framework to capture complex photonic–electronic interactions is demonstrated through three application examples, highlighting its effectiveness for co-simulating photonic devices with control and receiver electronics.