A Single TE01 Mode Fiber Laser

In this paper, we propose and experimentally demonstrate a fiber laser operating at single azimuthally polarized mode (TE
₀₁
mode) and stably outputting cylindrical vector beam. We use the self-designed ring-core fibers, which have an annular guided mode layer, to break the degeneracy of LP
₁₁
mode and make TE
₀₁
mode propagate stably in the fibers. A pair of fiber Bragg gratings which is inscribed on the passive ring-core fibers is used as the reflector and output coupler. A mode selective device is used to introduce different propagating losses for different modes, which is fabricated by corroding the fiber clad and depositing a layer of gold in the fiber surface. The slope efficiency of the fiber laser is 7.5% and its mode purity is about 92.4%. We believe that this single TE
₀₁
mode fiber laser could be practically applied in a wide range of applications.