Few-mode fiber Bragg grating (FM-FBG) has wide applications in the field of multi-wavelength fiber lasers and fiber-optic sensing. In this letter, FBG is successfully written in a novel type of FM fiber (FMF) based on 248-nm excimer laser and a uniform phase mask. A low-loss coupling between the FMF to a singlemode fiber is realized by a graded-index multi-mode fiber with a length of about a quarter pitch. The sensing properties of the FMF grating are further investigated. The experimental results indicate that the novel FM-FBG has sensitivities of temperature, strain, and bending of 11.2 pm/°C, 1.3 pm/με, and 636.9 pm/m-1, respectively.
© 2013 Chinese Optics Letters
Peng Guo, Yunjiang Rao, Dengyong Li, Yuan Gong, Gangding Peng, Yu Wu, Weili Zhang, and Huijuan Wu, "Inscription of Bragg gratings in few-mode optical fibers," Chin. Opt. Lett. 11, 020606- (2013)