Suppression of the fundamental mode in a dual-mode photonic crystal fiber

For the first time, the fundamental mode of a dual-mode photonic crystal fiber (PCF) is suppressed by the index-matching between the core and cladding modes. The PCF designed proposes a new solution of selective excitation of second-order modes. The simulation results demonstrate that the confinement loss of the fundamental mode is higher than 1 dB/m, while the second-order modes are lower than 10−4 dB/m in the C+L waveband. The high feasibility and low wavelength dependence make the fiber of great potential in the mode-division multiplexing (MDM) transmission.