{"DOI":"10.1038/s41598-020-80174-8","PMCID":"PMC7807047","PMID":"33441726","abstract":"AbstractMultimode optical switch is a key component of mode division multiplexing in modern high-speed optical signal processing. In this paper, we introduce for the first time a novel 2\u2009\u00d7\u20092 multimode switch design and demonstrate in the proof-of-concept. The device composes of four Y-multijunctions and 2\u2009\u00d7\u20092 multimode interference coupler using silicon-on-insulator material with four controllable phase shifters. The shifters operate using thermo-optic effects utilizing Ti heaters enabling simultaneous switching of the optical signal between the output ports on four quasi-transverse electric modes with the electric power consumption is in order of 22.5 mW and the switching time is 5.4\u00a0\u00b5s. The multimode switch exhibits a low insertion loss and a low crosstalk below \u2212\u20093\u00a0dB and \u2212\u200919\u00a0dB, respectively, in 50\u00a0nm bandwidth in the third telecom window from 1525 to 1575\u00a0nm. With a compact footprint of 10\u00a0\u00b5m\u2009\u00d7\u2009960\u00a0\u00b5m, this device exhibits a relatively large width tolerance of\u2009\u00b1\u200920\u00a0nm and a height tolerance of\u2009\u00b1\u200910\u00a0nm. Furthermore, the conceptual principle of the proposed multimode switch can be reconfigurable and scalable in multifunctional on-chip mode-division multiplexing optical interconnects.","author":[{"family":"Truong","given":"Cao Dung"},{"family":"Nguyen Thi Hang","given":"Duy"},{"family":"Chandrahalim","given":"Hengky"},{"family":"Trinh","given":"Minh Tuan"}],"id":"unknown","issue":"1","issued":{"date-parts":[[2021,1,13]]},"language":"en","page-first":"897","publisher":"Springer Science and Business Media LLC","title":"On-chip silicon photonic controllable 2\u2009\u00d7\u20092 four-mode waveguide switch","type":"article-journal","volume":"11"}