  So far, performance prediction and optimization of microwave SQUID
multiplexers has largely been based on simple approximate analytical models and
experimental results. This is caused by the complexity of the underlying
physics and the intricacy of operation and readout parameters. As a simplified
description can never account for all potential effects occurring in a real
device, we have developed a software framework to simulate the characteristics
and performance of a microwave SQUID multiplexer. Our simulation framework is a
powerful tool to guide understanding and optimization of microwave SQUID
multiplexers and other related devices. It includes common readout schemes such
as open-loop or flux ramp modulated readout as well as the nonlinear behavior
of Josephson tunnel junctions. Moreover, it accounts for the non-zero response
time of superconducting microwave resonators with high loaded quality factors
as well as the most significant noise contributions such as amplifier noise,
resonator noise as well as SQUID noise. This ultimately leads to a prediction
of device performance that is significantly better as compared simple
analytical methods. Using the simulation framework, we discuss first steps
towards a full microwave SQUID multiplexer optimization and highlight some
other applications which our simulation framework can be used for.
