Conical Double-Core Structure LPmn Mode Converter

In this work, a LP
_mn
mode converter is proposed based on a tapered double-core structure. With opposite changes of the two cores in radius dimension, matching the effective refractive index between the fundamental mode (LP
₀₁
) in one core and one desired high-order mode in the other core is obtained, and the fundamental mode power is gradually converted to the high-order mode. The simulation results show that the mode conversion of LP
₀₁
to any high-order mode of LP
₁₁
, LP
₂₁
, LP
₃₁
, LP
₁₂
, LP
₄₁
, LP
₂₂
, LP
₃₂
, LP
₄₂
and LP
₂₃
modes can be obtained with a conversion efficiency of ~99%, ~96%, ~92%, ~93%, ~82%, ~92%, ~84%, ~85% and ~81% at the working wavelength of 1550 nm, respectively, and also conversion bandwidth (>80% conversion efficiency) is 265, 125, 130, 130, 100, 35 and 30 nm, respectively. Compared to the previously reported works, the proposed mode converter structure is more universal to support any of higher-order mode conversions with wider bandwidth.