title: Absolute distance sensing by two laser optical interferometry.
abstract: We have developed a method for absolute distance sensing by two laser optical interferometry. A particularity of this technique is that a target distance is determined in absolute and is no longer limited to within an ambiguity range affecting usually multiple wavelength interferometers. We implemented the technique in a low-finesse Fabry-Pérot miniature fiber based interferometer. We used two diode lasers, both operating in the 1550 nm wavelength range. The wavelength difference is chosen to create a 25 μm long periodic beating interferometric pattern allowing a nanometer precise position measurement but limited to within an ambiguity range of 25 μm. The ambiguity is then eliminated by scanning one of the wavelengths over a small range (3.4 nm). We measured absolute distances in the sub-meter range and this with just few nanometer repeatability.
authors.affiliation: attocube systems AG, Königinstraße 11a RGB, 80539 München, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Thurner
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Braun
authors.forename: Khaled
authors.initials: K
authors.lastname: Karrai