Photonics Research, 2019, 7 (12): 12001479, Published Online: Nov. 21, 2019
Cylindrical vector beam fiber laser with a symmetric two-mode fiber coupler Download: 794次
Abstract
We demonstrate a passively mode-locked all-fiber laser generating cylindrical vector beams (CVBs) only using a symmetric two-mode fiber optical coupler (TMF-OC) for both high-order mode excitation and splitting. Theoretical analyses show that for a symmetric TMF-OC with appropriate taper diameter, the second-order mode can be excited and coupled into output tap with high purity due to the effective index difference of different modes. Based on the fabricated TMF-OC, the passively mode-locked fiber laser delivers pulsed CVBs at a center wavelength of 1564.4 nm with 3 dB linewidth of 11.2 nm, pulse duration of 2.552 ps, and repetition rate of 3.96 MHz. The purity of both radially and azimuthally polarized beams is estimated to be over 91%. Due to simple fabrication method of the TMF-OC and high purity of the generated CVBs, this mode-locked CVB fiber laser with all-fiber configuration has potential applications in optical trapping, optical communications, material processing, etc.
Yang Xu, Su Chen, Zhiqiang Wang, Bing Sun, Hongdan Wan, Zuxing Zhang. Cylindrical vector beam fiber laser with a symmetric two-mode fiber coupler[J]. Photonics Research, 2019, 7(12): 12001479.