摘要
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 d B linewidth of 11.2 nm,pulse duration of 2.552 ps,and repetition rate of3.96 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.
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 d B linewidth of 11.2 nm, pulse duration of 2.552 ps, and repetition rate of3.96 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.
基金
National Natural Science Foundation of China(91950105)
Natural Science Foundation of Jiangsu Province(BK20161521,BK20180742)
Nanjing University of Posts and Telecommunications Talents(NY214002,NY215002)
Distinguished Professor Project of Jiangsu(RK002STP14001)
Six Talent Peaks Project in Jiangsu Province(2015-XCL-023)
Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX18_0856)
