Effect Of External Angle And Annealing Technology On Tilted Fiber Gratings

Fiber gratings is one of the fiber optics passive components, by virtue of its small size, light weight, high sensitivity, good stability, intrinsically safe in national life, military, aerospace and other fields has been applied.Tilted fiber Bragg grating (TFBG) is a kind of fiber gratings whose grating has a certain angle perpendicular to the fiber axis, its refractive index modulation and the period are uniform. Because of tilted angle, not only does it have the advantages of the ordinary FBG, but also have the advantages of the long-period gratings. Therefore, in all-optical communication and sensing, it become a research hotspot.This thesis is based on Maxwell’s equations,with the the ordinary FBG coupled mode theory and a schematic view, a better understanding of FBG coupled mode theory and mode radiation is got. An overview of the traditional method of making FBG is completed. We use the method of operating a simple and low cost rotating mask method combined with conventional phase mask method, fabricated a group of TFBG. Because of the manufacture process and the Talbot effect, The internal angle of TFBG didn’t coincided and rapid increased with external angle increasing by this method. We studied this phenomenon, there is a certain linear relationship found between internal angle and external angle. After annealing, The relationship of between internal angle(θint)and external angle(θext)can be expressed as θint=0.0286+1.10616θext. In order to improve the stability of the TFBG, we studied the annealing process on the center wavelength drift effects, the results show that the annealing TFBG reflection center wavelength is blue-shifted, and the blue shift with increasing tilted angle become smaller and smaller. The results have a certain significance for TFBG fabrication...