title: Direct period measurement for fiber Bragg grating using an optical imaging technique.
abstract: This paper proposes an approach based on an optical imaging technique for the period measurement of fiber Bragg gratings (FBG). The simple, direct technique involves a differential interface contrast (DIC) microscope and a high-resolution CCD camera. Image processing is performed on the microscope images to obtain low-noise grating profiles and then the grating periods. Adopting a large image sample size in the image processing can reduce uncertainty. During the investigation, FBGs of different grating periods are fabricated by prestraining the photosensitive fibers during the UV-writing process. A good linearity between the measured Bragg wavelengths and grating periods is observed and the measured strain-optics coefficient was found to be in agreement with reported literature.
authors.affiliation: Photonics Research Centre, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: M M
authors.initials: MM
authors.lastname: Ali
authors.forename: K S
authors.initials: KS
authors.lastname: Lim
authors.forename: H Z
authors.initials: HZ
authors.lastname: Yang
authors.forename: W Y
authors.initials: WY
authors.lastname: Chong
authors.forename: W S
authors.initials: WS
authors.lastname: Lim
authors.forename: H
authors.initials: H
authors.lastname: Ahmad