We demonstrate the development of femtosecond laser inscribed superstructure fiber gratings (fsSFG) in silica optical fibre. We utilise a single step process, to inscribe low loss and polarisation independent, sampled gratings in optical fibres using the point by point femtosecond laser inscription method. Our approach results in a controlled modulated index change with complete suppression of any overlapping LPG structure leading to highly symmetric superstructure spectra, with the grating reflection well within the Fourier design limit. We also solve Maxwell's equations and calculate the back reflection spectrum using the bidirectional beam propagation method (BiBPM). Experimental results validate our numerical analysis and the estimation of inscription parameters such as ac index modulation, wavelength and the relative peak strength. We also explore how changes in the grating's period influence the reflection spectrum.
|Conference||21st International Conference on Optical Fiber Sensors|
|Period||15/05/11 → 19/05/11|
K. Kalli, C. Koutsides, E. Davies, M. Komodromos, D. J. Webb and L. Zhang, "Femtosecond laser inscribed superstructure fibre gratings", Proc. SPIE 7753, 775393 (2011). 21st International Conference on Optical Fiber Sensors (OFS21), 15-19 May 2011, Ottawa (CA).
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- femtosecond laser inscribed superstructure fiber gratings
- silica optical fibre
- single step process
- low loss
- polarisation independent
- sampled gratings
- optical fibres
- point by point femtosecond laser inscription method
- controlled modulated index change
- symmetric superstructure spectra
- grating reflection
- Fourier design limit
- Maxwell's equations
- back reflection spectrum
- bidirectional beam propagation method
- ac index modulation
- peak strength