Time-domain model for Advanced LIGO interferometer

A time-domain model for AdvLIGO interferometer has been implemented using LIGO End to End simulation framework. AdvLIGO interferometer configuration is a dual-recycled Fabry-Perot Michelson. The system is highly complex: it requires a good understanding in the control of the microscopic positions of seven mirrors to keep five strongly-coupled interferometric degrees of freedom at their working point. The transition from the uncontrolled to the controlled state (lock acquisition) necessitates a time-domain simulation to understand and guide the lock acquisition process using fast feedback systems. A productive interplay between simulation and experiment is required to achieve a good result. AdvLIGO interferometer is not yet ready but its configuration will be tested at CalTech's 40 m laboratory in the near future, as it is the closest experiment to AdvLIGO. The time-domain model is built-up using macros to define IFO parameters: in this way one is able to switch easily between the 40 m configuration and the Advanced LIGO configuration.