Ring resonator is an essential element in silicon integrated circuit, it is widely used as filter, wavelength multiplexer and switch in single-mode operation regime. As the rapid development of mode division multiplexing (MDM) technique, ring resonator that can process multimode signals simultaneously and uniformly is highly desired. However, the severe modal dispersion makes identical transmission for different modes very hard. In this paper, by breaking through the limitation of conventional multi-mode manipulation design with evanescent coupling or mode interference, we propose and demonstrate a multi-mode ring resonator (MMRR) inspired by the free space geometric optics. Arbitrary number of supporting modes can be achieved by simply widening the waveguide width. For proof-of-concept demonstration, an MMRR supporting four modes is fabricated with uniform transmittance. Furthermore, architecture of cascaded four MMRRs are also demonstrated experimentally.
Bibliographical noteFunding Information:
This work was supported by the National Key Research and Development Program of China (2019YFB1803801, 2019YFB2203502), National Natural Science Foundation of China (61922034, 61911530161), Program for HUST Academic Frontier Youth Team (2018QYTD08).
© 2021 Mengyuan Ye et al., published by De Gruyter.
- Geometrical optics
- Integrated optics devices
- Ring resonator