Input spectrum for heterodyne detection in advanced gravitational wave detectors without non-stationary shot-noise

Abstract

Future interferometric gravitational wave detectors will make use of the coupling between shot noise and radiation pressure noise that produces a squeezed output for the quantum noise at the dark-port of the interferometer allowing these interferometers to operate with a sensitivity that exceeds the standard quantum limit at certain frequencies. The ability of the detector to take advantage of this squeezed output state depends in part on the readout system used. With the phase modulated laser input planned for these interferometers the quantum-noise limited sensitivity is slightly better when homodyne (rather than heterodyne) detection is used. We show that by modifying the laser input spectrum for these interferometers, readout with heterodyne detection can be made to have the same quantum-noise limited sensitivity as readout with homodyne detection.

10 pages with 6 figures

References in corpus (4)

• Conversion of conventional gravitational-wave interferometers into QND interferometers by modifying their input and/or output optics
• Quantum noise in second generation, signal-recycled laser interferometric gravitational-wave detectors
• Quantum noise in laser-interferometer gravitational-wave detectors with a heterodyne readout scheme
• New Photodetection Method Using Unbalanced Sidebands for Squeezed Quantum Noise in Gravitational Wave Interferometer