title: Origin of spectral modal noise in fiber-coupled spectrographs.
abstract: We describe the origin of spectral modal noise in a fiber-coupled spectrograph. Prior investigations of this phenomenon have considered optical fibers with large cores that support thousands of optical modes and used a statistical treatment to analyze spectral noise that arises from interference between the modes. We examine spectral modal noise for a fiber-coupled spectrograph with a smaller-diameter fiber core, optimized for adaptively corrected telescopes, that supports only a few propagating modes for visible and near-infrared light. Simulations to predict the minimum amount of fiber stretch required to shift spectral oscillations by a half-period are confirmed by experiment.
authors.affiliation: Optical Sciences Center, University of Arizona, Tucson 85721, USA. cchen@optics.arizona.edu
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Chen
authors.forename: Robert O
authors.initials: RO
authors.lastname: Reynolds
authors.forename: Alan
authors.initials: A
authors.lastname: Kost