De Vine, GlennRabeling, DSlagmolen, Bram Johannes JozefLam, TimothyChua, Sheon (SSSY)Wuchenich, DanielleMcClelland, DavidShaddock, Daniel2010-07-162010-12-202010-07-162010-12-20Optics Express 17.2 (2009): 828-8371094-4087http://hdl.handle.net/10440/1043http://digitalcollections.anu.edu.au/handle/10440/1043Digitally enhanced heterodyne interferometry is a laser metrology technique employing pseudo-random codes phase modulated onto an optical carrier. We present the first characterization of the technique’s displacement sensitivity. The displacement of an optical cavity was measured using digitally enhanced heterodyne interferometry and compared to a simultaneous readout based on conventional Pound-Drever-Hall locking. The techniques agreed to within 5 pm/√Hz at 1 Hz, providing an upper bound to the displacement noise of digitally enhanced heterodyne interferometry. These measurements employed a real-time signal extraction system implemented on a field programmable gate array, suitable for closed-loop control applications. We discuss the applicability of digitally enhanced heterodyne interferometry for lock acquisition of advanced gravitational wave detectors.10 pages"OSA will grant the authors permission to deposit the publisher’s pdf from their Optics Express articles into the repository with the proper citation (reference number or journal /volume/page/year citation)." - from email received from Authorized Agent, The Optical Society, 27/05/10instrumentation, measurement, and metrologyheterodyne detectors2009-01-0910.1364/OE.17.0008282015-12-08