“…PCF has many unique optical characteristics compared with traditional fiber, such as: single-mode transmission characteristics with no cut-off wavelength, extremely low loss, adjustable nonlinearity, good dispersion characteristics, high birefringence characteristics, super-continuum generation, etc. [1][2], and has wide application prospects in sensing [3], fiber lasers [4][5], beam splitters [6][7], medical imaging [8]and many other fields. Therefore, since the first photonic crystal fiber came out in 1996, it has received wide attention.…”