Femtosecond laser writing of fibre Bragg gratings in large diameter air-clad optical fibre

Nathaniel Groothoff*, Netnanja Jovanovic, Graham D. Marshall, John Canning, Michael J. Withford

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Fibre Bragg gratings were written in large diameter (∼300-400 μm) air-clad optical fibre using an amplified Ti:Sapphire femtosecond laser (800 nm, 100 fs, 0-3 μJ/pulse) with the point-by-point method. Utilising multiphoton absorption, we induced modifications in the core of the air-clad fibre. By focusing the femtosecond laser close to the diffraction limit with a 20 × oil immersion microscope objective lens, the glass modification region is of the order of 1μm in the fibre, which has a 5 μm core diameter. A technique to avoid the scattering effect of the large air-silica index contrast, on the femtosecond radiation, was implemented. Grating rejection strengths of 20 dB were achieved with an accompanying insertion loss of 3-4 dB at 1085 nm.

Original languageEnglish
Pages (from-to)75-78
Number of pages4
JournalGlass Technology: European Journal of Glass Science and Technology Part A
Volume50
Issue number1
Publication statusPublished - Feb 2009

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