Phase-shifted gratings fabricated with femtosecond laser by overlapped two types of fiber Bragg gratings

A phase-shifted fiber Bragg grating (PS-FBG) fabricated by femtosecond laser phase mask technique is demonstrated. The PS-FBG fabricated by overlapped two types of fiber Bragg gratings (FBGs), which is a normal FBG and a titled fiber Bragg grating (TFBG). They are inscribed one over the other on the same section in a singlemode fiber. We researched the effect of different tilt angles to the Bragg wavelength of TFBG. The intensity and wavelength of PS-FBGs can be changed by controlling tilt angles. The method has advantages of simple and efficient fabrication as well as high-quality spectrum. Meanwhile it has a good repeatability. Additionally, the strain and temperature sensitivities of the 0 degrees + 3 degrees PS-FBG are experimentally measured, which are 0.867 pm/mu epsilon and 14.91 pm/degrees C, respectively.