A Two-Mode (De)Multiplexer Based on Multimode Interferometer Coupler and Y-Junction on InP Substrate

A two-mode (de)multiplexer [(DE)MUX] based on a multimode interferometer coupler and a symmetric Y-junction coupler is proposed and demonstrated on an InP substrate. By introducing a phase shifter section with a thickness-detuned core layer, a miniature two-mode (DE)MUX with mode conversion of 100% is designed and demonstrated. Simulation shows that the total length of the device can be as small as 446 μm: much shorter than other mode (DE) MUX in InP materials. Within the entire C-band wavelength range, the calculated insertion loss of the device is less than 0.7 dB, and the crosstalk is below -24 dB. A mode (DE) MUX was fabricated in InP materials, and the mode conversion of the TE
₀
and TE
₁
modes were successfully demonstrated.