Chapter 12: Simulation methods for advanced interferometers

This chapter provides an introduction to laser interferometer simulations for advanced gravitational-wave detectors. The single optical components involved in these detectors are simple, but in combination, can produce new complex systems. The stringent requirements on the sensitivity of the instruments demand accurate predictions and prevent us from artificially reducing the complexity of our models. Over the years the gravitational-wave research community has developed its own set of simulation packages adapted for the specific requirements of this field. In this chapter we aim to provide insight into the features and limitations of the existing models and the algorithms on which they are based. Our aim is to give an overview of the typical optical simulation tools developed to support the design, commissioning and characterization of advanced detectors. At the same time we hope to provide enough details so that interested readers would be able to program a basic optical model themselves. We also provide a dedicated webpage www.gwoptics.org/AdvDetectorBook with code samples accompanying this chapter. The code is presented in the form of Python notebooks that contain simple interactive examples for the main modeling methods discussed below.