We experimentally demonstrated a method of generating continuously wavelength-switchable optical vortex beams （OVBs） in an all-fiber laser. A polarization-dependent microknot resonator （MKR） functions as comb filt...We experimentally demonstrated a method of generating continuously wavelength-switchable optical vortex beams （OVBs） in an all-fiber laser. A polarization-dependent microknot resonator （MKR） functions as comb filter and accounts for the narrow linewidth （0.018 nm） of multlwavelength channels. The wavelength interval corresponds to the free spectral range of the MKR. We exploit a fused SMF-FMF （single mode fiber-few mode fiber） mode coupler to obtain broadband mode conversion and successfully achieve multiwavelength switchable OVBs. As far as we know, this is the first report about identical multiwavelength vortex beams with topological charges of 4-1. It has been verified that each channel of the vortex beams preserves the same orbital angular momentum （OAM） properties through their dear spiral interferograms. Multiwavelength vortex beams with identical OAM properties are desirable for multiplexing, exchanging, and routing to further improve the capacity of optical fiber transmission.展开更多
基金National Natural Science Foundation of China(NSFC)(91750108,61635006)Science and Technology Commission of Shanghai Municipality(STCSM)(16520720900)Shanghai Education Development Foundation(SHEDF)(16SG35)
文摘We experimentally demonstrated a method of generating continuously wavelength-switchable optical vortex beams （OVBs） in an all-fiber laser. A polarization-dependent microknot resonator （MKR） functions as comb filter and accounts for the narrow linewidth （0.018 nm） of multlwavelength channels. The wavelength interval corresponds to the free spectral range of the MKR. We exploit a fused SMF-FMF （single mode fiber-few mode fiber） mode coupler to obtain broadband mode conversion and successfully achieve multiwavelength switchable OVBs. As far as we know, this is the first report about identical multiwavelength vortex beams with topological charges of 4-1. It has been verified that each channel of the vortex beams preserves the same orbital angular momentum （OAM） properties through their dear spiral interferograms. Multiwavelength vortex beams with identical OAM properties are desirable for multiplexing, exchanging, and routing to further improve the capacity of optical fiber transmission.
