High temperature sensing using higher-order-mode rejected sapphire-crystal fiber gratings

Chun Zhan, Jae Hun Kim, Jon Lee, Stuart Yin, Paul Ruffin, Claire Luo

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

8 Scopus citations

Abstract

In this paper, we report the fabrication of higher-order-mode rejected fiber Bragg gratings (FBGs) in sapphire crystal fiber using infrared (IR) femtosecond laser illumination. The grating is tested in high temperature furnace up to 1600 degree Celsius. As sapphire fiber is only available as highly multimode fiber, a scheme to filter out higher order modes in favor for the fundamental mode is theoretically evaluated and experimentally demonstrated. The approach is to use an ultra thin sapphire crystal fiber (60 micron in diameter) to decrease the number of modes. The small diameter fiber also enables bending the fiber to certain radius which is carefully chosen to provide low loss for the fundamental mode LP01 and high loss for the other high-order modes. After bending, less-than-2-nm resonant peak bandwidth is achieved. The grating spectrum is improved, and higher resolution sensing measurement can be achieved. This mode filtering method is very easy to implement. Furthermore, the sapphire fiber is sealed with hi-purity alumina ceramic cement inside a flexible high temperature titanium tube, and the highly flexible titanium tube offers a robust packaging to sapphire fiber. Our high temperature sapphire grating sensor is very promising in extremely high temperature sensing application.

Original languageEnglish (US)
Title of host publicationPhotonic Fiber and Crystal Devices
Subtitle of host publicationAdvances in Materials and Innovations in Device Applications
DOIs
StatePublished - 2007
EventPhotonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications - San Diego, CA, United States
Duration: Aug 26 2007Aug 27 2007

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6698
ISSN (Print)0277-786X

Other

OtherPhotonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications
Country/TerritoryUnited States
CitySan Diego, CA
Period8/26/078/27/07

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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