title: Extremely broadband, on-chip optical nonreciprocity enabled by mimicking nonlinear anti-adiabatic quantum jumps near exceptional points.
abstract: Time-asymmetric state-evolution properties while encircling an exceptional point are presently of great interest in search of new principles for controlling atomic and optical systems. Here, we show that encircling-an-exceptional-point interactions that are essentially reciprocal in the linear interaction regime make a plausible nonlinear integrated optical device architecture highly nonreciprocal over an extremely broad spectrum. In the proposed strategy, we describe an experimentally realizable coupled-waveguide structure that supports an encircling-an-exceptional-point parametric evolution under the influence of a gain saturation nonlinearity. Using an intuitive time-dependent Hamiltonian and rigorous numerical computations, we demonstrate strictly nonreciprocal optical transmission with a forward-to-backward transmission ratio exceeding 10 dB and high forward transmission efficiency (∼100%) persisting over an extremely broad bandwidth approaching 100 THz. This predicted performance strongly encourages experimental realization of the proposed concept to establish a practical on-chip optical nonreciprocal element for ultra-short laser pulses and broadband high-density optical signal processing.
authors.affiliation: Department of Physics, Hanyang University, Seoul 04763, South Korea.
authors.forename: Youngsun
authors.initials: Y
authors.lastname: Choi
authors.affiliation: Department of Physics, Hanyang University, Seoul 04763, South Korea.
authors.forename: Choloong
authors.initials: C
authors.lastname: Hahn
authors.affiliation: Department of Physics, Hanyang University, Seoul 04763, South Korea.
authors.forename: Jae Woong
authors.initials: JW
authors.lastname: Yoon
authors.affiliation: Department of Physics, Hanyang University, Seoul 04763, South Korea.
authors.forename: Seok Ho
authors.initials: SH
authors.lastname: Song
authors.affiliation: School of Electrical Engineering and Computer Science, University of Ottawa, 800 King Edward Avenue, Ottawa, Ontario, Canada K1N 6N5.|Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario, Canada K1N 6N5.|Centre for Research in Photonics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Pierre
authors.initials: P
authors.lastname: Berini