A photonic crystal fiber for supporting 30 orbital angular momentum modes with low dispersion

This paper proposes a novel photonic crystal optical fiber which can support 30 orbital angular momentum(OAM)modes transmission and possesses relatively flat and low dispersion.The OAM modes can be well-separated due to the large effective refractive index difference(above 10^-4)between the eigenmodes.The only material of the designed fiber is silica.The dispersion of each OAM mode is controlled in the range of 50-100 ps·nm^-1·km^-1 and the total dispersion variation is below 10 ps·nm^-1·km^-1 from 1500 nm to 1600 nm.Moreover,the confinement loss of each OAM mode is below 8.17×10^-10 dB/m at 1550 nm,and the nonlinear coefficients is less than 0.71 W^-1/km for all modes at 1550 nm.With all these good features,this proposed optical fiber is promising to be applied in fiberbased OAM communication systems.