Two kinds of tension in fiber Bragg gratings with cladding etched as the sinusoidal function

摘要

A new grating structure with cladding etched as the sinusoidal function along the length direction is introduced. The cladding area of the grating varies as the sinusoidal function along fiber axes. The coupled mode theory is used to analyze its performance. Compared with the linearly chirped grating, the new structure exhibits an ideal box spectrum with steep edges when the tension is applied on the gratings in two different ways. For the type B grating, without tension after writing, it has a bigger bandwidth utilization (BWU) than that of the type A grating with tension after writing. Compared with the type A grating, the type B one is more adaptable in fiber-optic communications and sensor systems.