Design and fabrication of 125-μm standard cladding diameter heterogeneous 8-core fiber with ultra-low crosstalk for C-band transmission

In this paper, a novel heterogeneous 8-core fiber, with a standard cladding diameter of 125μm, is proposed for C-band transmission. The structural parameters of 8-core fiber have been meticulously optimized through the utilization of an artificial intelligence-based algorithm, which resulted in a notable decrease in crosstalk and confinement loss, as the effective mode area of each core is sufficiently large to partially suppress the accumulation of nonlinear effects. The designed 8-core fiber was manufactured by traditional plasma chemical vapor deposition process. Besides, in order to implement the optical interconnection between single-mode fiber and 8-core fiber, a pair of corresponding fan-in/fan-out devices with low insertion loss have also been developed. The maximum crosstalk of designed 8-core fiber was measured to be -52.9dB/10km at 1550nm. Finally, using these fan-in/fan-out devices, we successfully demonstrated a 1.6Tbps (4x400G) self-homodyne coherent detection transmission in C-band over 10km, and the transmission characteristics were evaluated using a PDM-16QAM transceiver.