An MMI-Based Mode (DE)MUX by Varying the Waveguide Thickness of the Phase Shifter

A two-mode (de)multiplexer [(DE)MUX] based on multimode interference couplers on InP substrate is proposed and experimentally demonstrated. A phase shifting section with a variation of the waveguide thickness is introduced to precisely control the phase shift to realize 100% mode conversion efficiency and multiplexing. Performance analysis of the (DE)MUX is carried out numerically, showing excellent properties with insertion loss <;1.2 dB and crosstalk <;-18.4 dB for both the TE
₀
and TE
₁
mode within the whole C-band. The proposed device is also fabricated and demonstrated on InP substrate.