APOGEE fiber development and FRD testing

Sophia Brunner, Adam Burton, Jeff Crane, Bo Zhao, Frederick R. Hearty, John C. Wilson, Larry Carey, French Leger, Mike Skrutskie, Ricardo Schiavon, Steven R. Majewski

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Scopus citations


Development of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) near-infrared spectrograph has motivated thorough investigation into the properties and performance of optical fibers. The fiber selected for APOGEE is a step index, multi-mode fiber, developed by PolyMicro, with a 120μm low OH, fused silica core, 25μm cladding, and 10μm buffer. The instrument design includes a 40 meter fiber run, connecting the spectrograph to the 2.5m Sloan Digital Sky Survey (SDSS) telescope, and an additional 2.5 meter fiber segment located within the instrument dewar, a vacuum-sealed, cryogenic environment. This light path is convoluted and includes many transitions and connections where the beam is susceptible irrevocable loss. To optimize the spectrograph performance it is necessary to minimize the losses incurred in the fiber system, especially those resulting in focal ratio degradation (FRD). The focus of this research has been to identify potential sources of loss and where applicable, select material components to minimize this effect. There is little previous documented work concerning the performance of optical fibers within this wavelength band (1.5-1.7μm). Consequently, the following includes comprehensive explanations of the APOGEE fiber system components, our experimental design and optical test bed set-up, beam alignment procedures, fiber terminating and polishing techniques, and results from our examination of FRD as correlated with source wavelength, fiber length and termination, and environmental conditions.

Original languageEnglish (US)
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy III
EditionPART 1
StatePublished - Nov 12 2010
EventGround-Based and Airborne Instrumentation for Astronomy III - San Diego, CA, United States
Duration: Jun 27 2010Jul 2 2010


OtherGround-Based and Airborne Instrumentation for Astronomy III
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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