A new type of few-mode photonic crystal fiber with nearly-zero flattened dispersion properties

A new Few-mode photonic crystal fiber (FM-PCF) is designed. By adding leakage channels of mode and replacing the circular air-holes of the first central ring with elliptic air-holes, the confinement loss of second-order mode and the high order model can be greater than 1dB/m, while a more flattened dispersion curve can be realized. The impacts of the parameters of the FM-PCF on the dispersion properties are analyzed. The results indicate that the second-order odd mode LP
₁₁
(odd) was effectively suppressed to achieve the transmission of fundamental mode LP
₀₁
, second-order even mode LP
₁₁
(even), and third-order mode LP
₂₁
. The dispersion value in 1550nm of three mode are 0.13ps/(nm·km), 0.04ps/(nm·km), 0. 014ps/(nm·km) when PCF of Λ=20μm, d
₁
/Λ=0.85, d
₂
/Λ=0.4, so this PCF can achieve dispersion-flattened transmission in the wavelength range of communication.