skip to main content

SciTech ConnectSciTech Connect

Title: Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials

A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 GSamples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO₃. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L<10⁻⁴) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in themore » thermal ignition of the high explosive PBX-9501 is also demonstrated. In conclusion, both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.« less
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [1] ;  [3] ;  [3] ;  [1] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); National High Magnetic Field Lab., Los Alamos, NM (United States)
  3. National Security Technologies, Santa Barbara, CA (United States)
Publication Date:
OSTI Identifier:
1222269
Report Number(s):
LA-UR-15-22176
Journal ID: ISSN 1094-4087; OPEXFF
Grant/Contract Number:
AC52-06NA25396
Type:
Published Article
Journal Name:
Optics Express
Additional Journal Information:
Journal Volume: 23; Journal Issue: 11; Journal ID: ISSN 1094-4087
Publisher:
Optical Society of America (OSA)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; fiber Bragg gratings; equipment and techniques; fiber optics sensor; fiber measurements; pressure measurement; ultrafast technology; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; 47 OTHER INSTRUMENTATION; fiber optic sensors; ultrafast