title: Fringe-counting technique used to lock a suspended interferometer.
abstract: We implement a digital fringe-counting technique to measure in real time the relative mirror displacement of a suspended Michelson interferometer with modulated optical path length for oscillations much larger than the laser wavelength (λ). This provides the proper error signal for a servo mechanism that reduces the relative displacement within λ/2. The implemented technique does not require extra optics or polarizers and thus can be used for interferometric gravitational wave detectors as a starting procedure to get the system locked.
authors.forename: F
authors.initials: F
authors.lastname: Barone
authors.forename: E
authors.initials: E
authors.lastname: Calloni
authors.forename: R D
authors.initials: RD
authors.lastname: Rosa
authors.forename: L D
authors.initials: LD
authors.lastname: Fiore
authors.forename: F
authors.initials: F
authors.lastname: Fusco
authors.forename: L
authors.initials: L
authors.lastname: Milano
authors.forename: G
authors.initials: G
authors.lastname: Russo