This is the documentation for Finesse 3, which is in a alpha stage of development. You can find the documentation, executables and code for the stable Finesse 2 at http://www.gwoptics.org/finesse.


Finesse is a fast and easy to use Python-based interferometer simulation program. It uses frequency-domain optical modelling to build accurate quasi-static simulations of arbitrary interferometer configurations.

For convenience, a number of standard analyses can be performed automatically by the program, namely computing modulation-demodulation error signals, transfer functions, quantum-noise-limited sensitivities, and beam shapes. The optical system can be modelled using the plane-wave approximation or Hermite-Gauss modes, allowing the computation of optical systems like telescopes or the effects of mode matching and mirror angular positions.

Finesse is based on an object-oriented design and provides a large set of utility functions for ease of use when handling complex simulation tasks, for example:

  • chained simulations,

  • advanced plotting of outputs,

  • automated simulations,

  • the use of Jupyter notebooks to document simulation tasks,

  • and much more!