Broadband and High Conversion Efficiency Mode Converters Based on Sinusoidal Tapers

Mode converter is one of the important components in mode-division multiplexing (MDM) system. In this letter, we propose broadband and high conversion efficiency mode converters on silica-based PLC platform, in which sinusoidal taper waveguides are used for mode conversion. Symmetrical and asymmetrical shapes have been designed for odd and even order modes and the effect of fabrication error tolerance on the conversion efficiency has been researched. In the wavelength range of 1500 to 1630 nm, the conversion efficiency of E00-E10 and E00-E20 converters are higher than −0.856 dB (82.2%) and −1.286 dB (74.3%) according to the experimental results, respectively. At 1550 nm, two mode converters achieve conversion efficiencies of −0.386 dB (91.5%) and −0.359 dB (92.1%). Moreover, the degradation of conversion efficiency is less than 0.926 dB and 0.895 dB with the length deviation of
$\pm 10~\mu \text{m}$
.