title: Fiber-based distance sensing interferometry.
abstract: We present an interferometric displacement sensor based on a folded low-finesse Fabry-Perot cavity. The fiber-optic sensor uses a quadrature detection scheme based on the wavelength modulation of a DFB laser. This enables measuring position changes over a range of 1 m for velocities up to 2 m/s. The sensor is well suited to work in extreme environments such as ultrahigh vacuum, cryogenic temperatures, or high magnetic fields and supports multichannel applications. The interferometer achieves a repeatability of 0.44  nm(3σ) at a working distance of 20 mm, a resolution of 1 pm, and an accuracy of 1 nm.
authors.forename: Klaus
authors.initials: K
authors.lastname: Thurner
authors.forename: Francesca Paola
authors.initials: FP
authors.lastname: Quacquarelli
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Braun
authors.forename: Claudio
authors.initials: C
authors.lastname: Dal Savio
authors.forename: Khaled
authors.initials: K
authors.lastname: Karrai