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Proceedings Paper

Experimental demonstration of a broadband time-asymmetric waveguide architecture enabled by dynamically encircling an exceptional point in the optical domain (Conference Presentation)

Paper Abstract

We experimentally demonstrate a robust Si-photonic waveguide architecture that realizes dynamically encircling an exceptional point (EP) in the optical domain and broadband asymmetric modal transmission as an essential consequence. The structure consists of a pair of coupled channel waveguides and an adjacent slab-waveguide patch that enable precise lithographic controls on the phase velocities and radiation rates of the guided photonic modes. Complex modal index and inter-mode coupling constant profiles required for the encircling-an-EP parametric control are precisely coded in the geometry of those elements. The device created on this basis induces the symmetry-exchanging adiabatic state flip for one transmission direction and symmetry-preserving anti-adiabatic state-jump for the transmission in the opposite direction. In fabrication, we use a state-of-the-art electron-beam lithography for creating mm-long devices with nm-scale transversal precision. A comprehensive spectral measurement for the intensity and phase distributions of the transmitted optical states is obtained with a specially designed phase-sensitive infrared microscopy integrated with a tunable diode-laser system and spectrum analyzer. On this basis, we confirm in the experiment the highly asymmetric modal transmission persisting over a broad spectral band exceeding 100 nm in the telecommunications window around 1,550 nm. Hence, we establish a substantive experimental step toward broadband non-reciprocal photonic devices based on the unique non-Hermitian dynamics.

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10549, Complex Light and Optical Forces XII, 105490V (14 March 2018);
Show Author Affiliations
Jae Woong Yoon, Hanyang Univ. (Korea, Republic of)
Youngsun Choi, Hanyang Univ. (Korea, Republic of)
Choloong Hahn, Hanyang Univ. (Korea, Republic of)
Ki Yeon Yang, Samsung Advanced Institute of Technology (Korea, Republic of)
Jeong Yub Lee, Samsung Advanced Institute of Technology (Korea, Republic of)
Gunpyo Kim, Hanyang Univ. (Korea, Republic of)
Jong Kyun Hong, Hanyang Univ. (Korea, Republic of)
Yeonghwa Ryu, Hanyang Univ. (Korea, Republic of)
Seok Ho Song, Hanyang Univ. (Korea, Republic of)
Pierre Berini, Univ. of Ottawa (Canada)

Published in SPIE Proceedings Vol. 10549:
Complex Light and Optical Forces XII
Enrique J. Galvez; David L. Andrews; Jesper Glückstad, Editor(s)

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