Optical isolation with nonlinear topological photonics

• Published in: New journal of physics Vol. 19; no. 9; pp. 95002 - 95013
• Main Authors: Zhou, Xin, Wang, You, Leykam, Daniel, Chong, Y D
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 08.09.2017
• Subjects: Arrays; Isolators; optical isolators; Phase transitions; Photonics; Physics; Solitary waves; solitons; topological photonics; Topology; Transmittance; Two dimensional models; Waveguides
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/aa7cb5

It is shown that the concept of topological phase transitions can be used to design nonlinear photonic structures exhibiting power thresholds and discontinuities in their transmittance. This provides a novel route to devising nonlinear optical isolators. We study three representative designs: (i) a waveguide array implementing a nonlinear 1D Su-Schrieffer-Heeger model, (ii) a waveguide array implementing a nonlinear 2D Haldane model, and (iii) a 2D lattice of coupled-ring waveguides. In the first two cases, we find a correspondence between the topological transition of the underlying linear lattice and the power threshold of the transmittance, and show that the transmission behavior is attributable to the emergence of a self-induced topological soliton. In the third case, we show that the topological transition produces a discontinuity in the transmittance curve, which can be exploited to achieve sharp jumps in the power-dependent isolation ratio.