Silicon three-mode (de)multiplexer based on cascaded asymmetric Y junctions

Abstract

A three-mode (de)multiplexer based on two cascaded asymmetric Y junctions is proposed and experimentally demonstrated on a silicon-on-insulator platform for mode-division multiplexing applications. Within a bandwidth from 1537 to 1566 nm, the best demultiplexing crosstalk of the fabricated device, composed of a three-mode multiplexer, a multimode straight waveguide, and a three-mode demultiplexer, is up to -31.5 dB, while in the worst case it is -9.7 dB. The measured maximum insertion loss is about 5.7 dB at a wavelength of 1550 nm. The mode crosstalk and insertion loss can be further improved by high-quality fabrication processes.