Low Thermal Sensitivity Grating Devices Based on Ex-45$^{\circ}$ Tilting Structure Capable of Forward-Propagating Cladding Modes Coupling

Kaiming Zhou, Lin Zhang, Xianfeng Chen, Ian Bennion
2006 Journal of Lightwave Technology  
We describe a detailed investigation on tilted fiber Bragg grating (TFBG) structures with tilted angles exceeding 45°. In contrast to the backward mode coupling mechanism of Bragg gratings with normal and small-tilting structures, the ex-45°TFBGs facilitate the light coupling to the forward propagating cladding modes. We have theoretically and experimentally examined the mode coupling transition of TFBGs with small, medium and large tilt angles. In particular, we have conducted experiments to
more » ... ed experiments to investigate the spectra and far field distribution, and temperature, strain and refractive index sensitivities of ex-45° devices. It has been revealed that these ex-45°gratings exhibit ultra-low thermal sensitivity. As in-fiber devices, they may be superior to conventional Bragg and long period gratings when the low thermal cross sensitivity is required. K from Eq.2. On the other hand, we can also use Eq.2 to design a grating with particular tilt structure for light at certain wavelength to be radiated in a desired direction.
doi:10.1109/jlt.2006.884985 fatcat:t5lly6v2nng75gp7bhvuglxldq