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 center dot nm(-1)center dot km(-1) and the total dispersion variation is below 10 ps center dot nm(-1)center dot km(-1) from 1 500 nm to 1 600 nm. Moreover, the confinement loss of each OAM mode is below 8.17x10(-10) dB/m at 1 550 nm, and the nonlinear coefficients is less than 0.71 W-1 /km for all modes at 1 550 nm. With all these good features, this proposed optical fiber is promising to be applied in fiber-based OAM communication systems.