Fibre Bragg gratings (FBGs) are usually fabricated by UV laser light (typically, 248 nm radiation from a KrF* excimer laser), which spectrally coincides with the absorption band of defects in germanosilicate fibre core [1, 2]. Recently, it was demonstrated that the use of highintensity femtosecond UV pulses leads to an improvement of the inscription efficiency in photosensitive fibres due to realisation of the two-step excitation process S0!S1!SN [3, 4]. The possibility of such an improvement follows from the consideration of the scheme of the electronic levels for the germanium sites in fused silica glass and corresponding defects . In this Letter we study FBG recording in a highly-nonlinear fibre (HNLF, OFS Denmark), employing 264 nm femtosecond pulses with a peak intensity of around 180 GW=cm2. refractive fluence, kJ/cm2.
|Publication status||Published - 2004|
Slattery, S. A., Nikogasyan, D. N., Plougmann, N., Sørensen, H. R., & Kristensen, M. (2004). Efficient bragg grating fabrication in Ge-rich fibre by high-intensity femtosecond 264 mm irradation. Electronics Letters, 40(23), 1472-1473.