Control System Design for the LIGO Pre-stabilized Laser

To meet the strain sensitivity requirements [1], [2] of the Laser Interferometer Gravitational Wave Observatory (LIGO), the laser frequency and amplitude noise must initially be reduced by a factor of 1000 in the pre-stabilized portion of the interferometer [3]. A control system was implemented to provide laser noise suppression, data acquisition interfaces, diagnostics, and operator control inputs. This paper describes the VME-based analog and digital controls used in the LIGO Pre-stabilized Laser (PSL).