All-fiber cylindrical vector beams laser based on an acoustically-induced fiber grating

We presented a method to construct an all-fiber laser by using an acoustically-induced fiber grating (AIFG) in two-mode fiber (TMF) within the laser cavity to generate cylindrical vector beams (CVBs) in communication band. Based on the polarization dependent vector mode coupling characteristic of an AIFG, the CVBs were generated by respectively coupling HE11 x and HE11 y modes to TM01 and TE01 modes, which have radial and azimuthal polarizations characteristics, respectively. The output of the all-fiber laser could be adjusted from a linearlypolarized Gaussian mode to a radially or an azimuthally polarized vector mode through a polarization controller to adjust the linear polarization direction of the input mode of H11 x y and an acoustic flexural wave applied on TMF. This work provides a method for generating CVBs with convenient mode conversion characteristics.