We propose a new interferometer technique for high precision phase measurements such as those in gravitational wave detection. The technique utilizes a pair of optically coupled resonators that provides identical resonance conditions for the upper as well the lower phase modulation signal sidebands. This symmetry significantly reduces the noise spectral density in a wide frequency band compared with single sideband recycling topologies of current and planned gravitational wave detectors. Furthermore the application of squeezed states of light becomes less demanding.
@article{arxiv.0707.0413,
title = {Detuned Twin-Signal-Recycling for ultra-high precision interferometers},
author = {Andre Thuering and Roman Schnabel and Harald Lueck and Karsten Danzmann},
journal= {arXiv preprint arXiv:0707.0413},
year = {2007}
}