Hole-Assisted Few-Mode Multicore Fiber for High-Density Space-Division Multiplexing

Abstract

A seven-core few-mode multicore fiber in which each core supports both the LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> mode and the two degenerate LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> modes has been designed and fabricated for the first time, to the best of our knowledge. The hole-assisted structure enables low inter-core crosstalk and high mode density at the same time. LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> inter-core crosstalk has been measured to be lower than -60 dB/km. LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> inter-core crosstalk has been measured to be around -40 dB/km using a different setup. The LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> free-space excitation-induced crosstalk is simulated and analyzed. This fiber allows multiplexed transmission of 21 spatial modes per polarization per wavelength. Data transmission in LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub> /LP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> mode over 1 km of this fiber has been demonstrated with negligible penalty.