Multicore chalcogenide photonic crystal fibers for large mode area and mode shaping

Phase locking and mode shaping in multicore Ge20Sb15S65 chalcogenide photonic crystal fibers are proposed and demonstrated. By manipulating the geometrical structure of the fibers, a large mode area of 1962 µm2 resulting from in-phase supermodes and equal amplitudes was obtained, which can significantly reduce the nonlinear damage in chalcogenide fibers in the infrared spectrum. With the coherent beam combining technology of multicore photonic crystal fibers, the far-field combining beam exhibits high brightness and high beam quality. Calculations show that with good phase locking and mode shaping, a seven-core photonic crystal fiber can achieve 49 times enhanced intensity compared with single-core fibers.