Long-period fibre grating fabrication with femtosecond pulse radiation at different wavelengths
P. G. Kryukova, Yu. V. Larionova, A. A. Rybaltovskiia, K. A. Zagorul'ko
, 
, a, A. Dragomirb, D. N. Nikogosyanb and A. A. Ruthb
a Fiber Optics Research Center, General Physics Institute, Russian Academy of Sciences, 38 Vavilov Street, 119991, Moscow, Russia
b National University of Ireland, University College Cork, Cork, Ireland
Available online 24 June 2003.
The fabrication of long-period fibre gratings (LPFGs) in optical fibres by femtosecond pulses at different wavelengths is reported. Several types of fibres were used and it was found that LPFGs with strong attenuation peaks (more than 20 dB) can be induced in hydrogen-loaded germanosilicate fibres using the second harmonic of a femtosecond Ti:sapphire laser without the use of an amplifier (400 nm, 70 fs and 2.5 nJ) and amplified, frequency-quadrupled pulses from a Nd:glass laser (264 nm, 220 fs and 0.4 mJ). Low `out-of-band' losses and results of isochronal annealing for the fabricated gratings suggest that the photoinduced refractive index change is not accompanied by damage to irradiated fibres.
Author Keywords: Fibre grating; Femtosecond laser; Excimer laser; Non-linear absorption; Photosensitivity
