Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1541733 | Optics Communications | 2006 | 8 Pages |
Abstract
Long period gratings (LPGs) were written into a D-shaped optical fibre that has an elliptical core with a W-shaped refractive index profile and the first detailed investigation of such LPGs is presented. The LPGs' attenuation bands were found to be sensitive to the polarisation of the interrogating light with a spectral separation of about 15 nm between the two orthogonal polarisation states. A finite element method was successfully used to model many of the behavioural features of the LPGs. In addition, two spectrally overlapping attenuation bands corresponding to orthogonal polarisation states were observed; modelling successfully reproduced this spectral feature. The spectral sensitivity of both orthogonal states was experimentally measured with respect to temperature and bending. These LPG devices produced blue and red wavelength shifts depending upon the orientation of the bend with measured maximum sensitivities of â3.56 and +6.51 nm m, suggesting that this type of fibre LPG may be useful as a shape/bend orientation sensor with reduced errors associated with polarisation dependence. The use of neighbouring bands to discriminate between temperature and bending was also demonstrated, leading to an overall curvature error of ±0.14 mâ1 and an overall temperature error of ±0.3 °C with a maximum polarisation dependence error of ±8 Ã 10â2 mâ1 for curvature and ±5 Ã 10â2 °C for temperature.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
T. Allsop, H. Dobb, V. Mezentsev, T. Earthgrowl, A. Gillooly, D.J. Webb, I. Bennion,