A wavelength-tunable narrow-linewidth all-fiber laser with cylindrical vector beam outputs

In this paper, we experimentally demonstrated wavelength-tunable cylindrical vector beams of very narrow spectral linewidth at ∼1μm with an authentic all-fiber structure for the first time to the best of our knowledge. An ytterbium-doped fiber laser was utilized to initiate the continuous-wave single-longitudinal-mode laser emission, and an off-set splice spot together with a few-mode fiber Bragg grating were used as the mode converter as well as mode selecting output coupler. By adjusting the built-in polarization controllers, radially and azimuthally polarized CVB outputs were both obtained. The central wavelength was at 1053.4 nm with a tuning range of 1.1 nm with thermal control, and two fiber Mach-Zehnder interferometers were cascaded to achieve a 20-dB linewidth of 14.7 kHz.