WDM-Compatible Polarization-Diverse OAM Generator and Multiplexer in Silicon Photonics

• Published in: IEEE journal of selected topics in quantum electronics Vol. 26; no. 2; pp. 1 - 7
• Main Authors: Chen, Yuxuan, Lin, Zhongjin, Villers, Simon Belanger-de, Rusch, Leslie A., Shi, Wei
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-03-2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Angular momentum; Antenna arrays; Apertures; Circular polarization; Coupling; Couplings; Crosstalk; Dependence; Electron beams; Emitters; Fiber optics; Heating systems; integrated photonic circuits; Linear polarization; Multiplexers; Multiplexing; Optical fibers; orbital angular momentum; Photonics; Polarization; Silicon; Silicon photonics; space division multiplexing; Two dimensional displays; Wave division multiplexing; Wavelength division multiplexing
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2019.2941488

Spatial multiplexing using orbital angular momentum (OAM) modes is an efficient means of scaling up the capacity of fiber-optic communications systems; integrated multiplexers are crucial enablers of this approach. OAM modes are circularly polarized when propagating in a fiber, however, OAM generators previously demonstrated in silicon photonics use locally linearly polarized emitters. Coupling from multiplexers to fibers in those solutions results in extra loss and complexity. Moreover, many of those solutions are based on resonator structures with strong wavelength dependence, and are thus incompatible with wavelength-division multiplexing (WDM). We experimentally demonstrate on-chip generation and multiplexing of OAM modes using an array of circularly polarized 2-D antennas with wide wavelength coverage. The proposed device was implemented on the standard 220-nm silicon-on-insulator platform. Optical vortex beams with OAM orders ranging from -3 to +3 in both left and right circular polarization states were generated from the same aperture across a wavelength range of 1540 to 1557 nm. This device could serve as a multiplexer or demultiplexer for up to 12 information bearing channels coupling into an OAM fiber, and is compatible with WDM multiplexing as well.