Influence of tension-induced photosensitivity change on the fabrication of Erbium-doped phase-shifted fiber gratings

In the fabrication of erbium-doped π-phase shift fiber gratings, which are the core components of distributed feedback fiber lasers, the relationship between optical fiber photosensitivity and tension is studied, and the influence on κL value of phase shift gratings and output characteristics of narrow linewidth laser is investigated. The experimental results show that under the same exposure and fabrication parameters, the greater the tension applied during exposure, the greater the reflectivity of the FBG, indicating higher photosensitivity. For doped fiber, the higher the tension, the worse the photosensitivity of the fiber.When the erbium-doped fiber used to fabricate phase-shifted fiber gratings the exposure needs to be increased to ensure that the κL value meets the lasing threshold condition if the tension applied on the fiber is adjusted to manipulate the operating wavelength, which will lead to worse power stability of DFB-FL compared with the devices made by lower tension and exposure.