INTERCONNECT frequency domain simulations provide steady-state complex transmission
spectra of photonic circuits using scattering analysis.
Each element in the circuit is characterized by a complex scattering matrix, or S-matrix,
that describes the relationship between its bidirectional ports as well as the relationship
between the modes supported.
The S-parameter simulator, called SPS for short, calculates the overall frequency domain
response of the circuit from the S-matrices of the individual elements.
Running a frequency domain simulation in INTERCONNECT requires the optical network analyzer also called
the ONA element, with the analysis type set to scattering analysis.
The ONA is placed in the layout and its output is connected to an element port to provide
a source signal to the circuit.
One or more of the ONA inputs are connected to element ports.
The ONA calculates the overall scattering matrix of the circuit, which is
used to extract the complex transmission, including the amplitude and phase of the optical signals.
Frequency domain simulations are particularly useful in studying photonic circuits in steady-state.
Some common results studied from frequency domain simulations include, transmission and
reflection spectra, group delay, and resonator properties such as free spectral range
and quality factor.
One of the main advantages of frequency domain simulations is that they are generally more
straight-forward to set up than time domain simulations as there are fewer considerations.
For this reason, even when a time domain simulation is ultimately of interest, a quick frequency
domain simulation can help you take a look at the circuit performance and identify problems.