Device and method for generating columnar vector beams in optical fiber by utilizing electrically-controlled tunable optical grating

The invention provides a device and a method for generating columnar vector beams in optical fiber by utilizing an electrically-controlled tunable optical grating. By means of the linear polarization characteristic of the electrically-controlled tunable optical grating, efficient coupling between a linear polarization vector basic mode in a fiber core and TM01 and TE01 modes can be realized, and a columnar vector light field with strict radial and angular polarization characteristics can be generated. Complete coupling between the linear polarization vector basic mode and the columnar vector light field can be realized by optimizing the refractive index modulation degree of the electrically-controlled tunable optical grating. Columnar vector light can be generated in different wavelength positions of the optical fiber conveniently by adjusting and modulating the period of the electrically-controlled tunable optical grating. The adopted device is simple and has high columnar vector light field generation efficiency, the generated columnar vector light beams have high mode purity, meanwhile, different radial and angular vector light fields can be conveniently converted, and the columnar vector light field can be generated in different wavelengths by adjusting radio-frequency signals.