Large mode-area chalcogenide multicore fiber prepared by continuous two-stage extrusion

A large mode-area (LMA) chalcogenide multicore fiber (MCF) with 13 hexagonally arranged cores has been designed and fabricated for mid-infrared (MIR) high power laser delivery. The dependence of mode distributions, bending loss and dispersion characteristics on the fiber structure parameters has been investigated by the method of finite element analysis at a wavelength range from 3 to 5 μm. An ultra-large fundamental mode (FM) effective area of ∼8000 μm2 as well as a low normal dispersion down to -46 ps/nm/km at 3 μm are theoretically obtained, which is of great benefit to high power MIR laser delivery. The fiber possesses a calculated low bending loss less than 0.075 dB/m as the bending radius is larger than 0.4 m. Finally, a well-structured 13-core fiber consisting of Ge9As23Se68 and Ge10As22Se68 glasses is fabricated via the continuous two-stage extrusion method, and this fiber shows a low optical loss of 0.28 dB/m at 6.6 µm, which is the lowest fiber loss for a micro-structured chalcogenide fiber obtained via extrusion, to the best of our knowledge.