Contributed Review: A review of compact interferometers.

Compact interferometers, called phasemeters, make it possible to operate over a large range while ensuring a high resolution. Such performance is required for the stabilization of large instruments dedicated to experimental physics such as gravitational wave detectors. This paper aims at presenting the working principle of the different types of phasemeters developed in the literature. These devices can be classified into two categories: homodyne and heterodyne interferometers. Improvement of resolution and accuracy has been studied for both devices. Resolution is related to the noise sources that are added to the signal. Accuracy corresponds to distortion of the phase measured with respect to the real phase, called non-linearity. The solutions proposed to improve the device resolution and accuracy are discussed based on a comparison of the reached resolutions and of the residual non-linearities.