In this work, an all-fiber-based mode converter for generating orbital angular momentum （OAM） beams is proposed and numerically investigated. Its structure is constructed by cascading a mode selective coupler （MSC...In this work, an all-fiber-based mode converter for generating orbital angular momentum （OAM） beams is proposed and numerically investigated. Its structure is constructed by cascading a mode selective coupler （MSC） and an inner elliptical cladding fiber （IECF）. OAM modes refer to a combination of two orthogonal LPlm modes with a phase difference of ±π/2. By adjusting the parameters and controlling the splicing angle of MSC and IECF appropriately, higher-order OAM modes with topological charges of l = ±1, ±2, ±3 can be obtained with the injection of the fundamental mode LP01, resulting in a mode-conversion efficiency of almost 100%. This achievement may pave the way towards the realization of a compact, all-fiber, and high-efficiency device for increasing the transmission capacity and spectral efficiency in optical communication systems with OAM mode multiplexing.展开更多
We propose a new type of dispersion-flattened waveguide without a slot-assisted structure that can obtain an ultra-flat group velocity dispersion profile with five or six zero-dispersion wavelengths in the mid-infrare...We propose a new type of dispersion-flattened waveguide without a slot-assisted structure that can obtain an ultra-flat group velocity dispersion profile with five or six zero-dispersion wavelengths in the mid-infrared region.The dispersion profile becomes less sensitive to the waveguide dimensions due to the absence of the slot-assisted structure,making waveguide fabrication more friendly.The dispersion profile varies between−0.472 and 0.365 ps/(nm·km)over a 2665 nm bandwidth from 2885 nm to 5550 nm with a flatness of 3183.99 nm2·km/ps.Two different combinations of materials are demonstrated for dispersion flattening of the proposed waveguide structures.We also provide design guidance for the proposed waveguide structures with other combinations of materials.展开更多
基金This work was supported by National Natural Science Foundation of China （Grant No. 61275049）.
文摘In this work, an all-fiber-based mode converter for generating orbital angular momentum （OAM） beams is proposed and numerically investigated. Its structure is constructed by cascading a mode selective coupler （MSC） and an inner elliptical cladding fiber （IECF）. OAM modes refer to a combination of two orthogonal LPlm modes with a phase difference of ±π/2. By adjusting the parameters and controlling the splicing angle of MSC and IECF appropriately, higher-order OAM modes with topological charges of l = ±1, ±2, ±3 can be obtained with the injection of the fundamental mode LP01, resulting in a mode-conversion efficiency of almost 100%. This achievement may pave the way towards the realization of a compact, all-fiber, and high-efficiency device for increasing the transmission capacity and spectral efficiency in optical communication systems with OAM mode multiplexing.
基金supported by the National Key Research and Development Program of China(No.2020YFB2205802).
文摘We propose a new type of dispersion-flattened waveguide without a slot-assisted structure that can obtain an ultra-flat group velocity dispersion profile with five or six zero-dispersion wavelengths in the mid-infrared region.The dispersion profile becomes less sensitive to the waveguide dimensions due to the absence of the slot-assisted structure,making waveguide fabrication more friendly.The dispersion profile varies between−0.472 and 0.365 ps/(nm·km)over a 2665 nm bandwidth from 2885 nm to 5550 nm with a flatness of 3183.99 nm2·km/ps.Two different combinations of materials are demonstrated for dispersion flattening of the proposed waveguide structures.We also provide design guidance for the proposed waveguide structures with other combinations of materials.
