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

• A novel PS-FBG was inscribed by overlapped a normal FBG and a TFBG. • The intensity and wavelength of PS-FBGs can be controlled by tilt angles. • The method has merits of simple fabrication and good repeatability. • The PS-FBG shows a high strain and temperature sensitivity. 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 single-mode 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° + 3° PS-FBG are experimentally measured, which are 0.867 pm/με and 14.91 pm/℃, respectively. [ABSTRACT FROM AUTHOR]