Goniometric characteristics of optical fibres for temperature measurement in diesel engine exhaust filters

Brian J. Boothe, Albert J. Shih*, Jian Kong, William Roberts

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The accurate in situ, non-contact measurement of the temperature distribution within diesel after-treatment filters requires the employment of optical fibres with special tip geometry. The goniometric characteristics of optical fibres with flat, 45° angled and bent and polished tips are studied such that the specific radiation acceptance region can be determined. One 2 mm diameter fused silica and two 0.425 mm diameter sapphire optical fibres are examined. Detailed discussion of the relative intensity profiles observed for these fibres is presented. Of the three fibres evaluated, the 45° angled tip geometry provides the most precise response for measuring radiation emitted from the internal filter walls. Exploiting the characteristics of total internal reflection, the 45° angled tip fibre accepts the maximum quantity of incident radiation at an angle perpendicular to the optical axis.

Original languageEnglish (US)
Pages (from-to)563-572
Number of pages10
JournalMeasurement Science and Technology
Issue number5
StatePublished - Jan 1 2003


  • Angled tip
  • Effective numerical aperture
  • Goniometric characteristics
  • Optical fibre

ASJC Scopus subject areas

  • Instrumentation
  • Engineering (miscellaneous)
  • Applied Mathematics

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