Frozen Mode in an Asymmetric Serpentine Optical Waveguide

Parareda, Albret Herrero; Vitebksiy, Ilya; Scheuer, Jacob; Capolino, Filippo

doi:10.1002/adpr.202100377

Cited by 12 publications

(3 citation statements)

References 29 publications

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“…The outer rings here act as Sagnac loop reflectors [30]. We note that even though variants of this geometry have been considered before for building various optical devices for different applications such as sensing, lasing, and information processing [31][32][33][34][35], the peculiar feature that we highlight in this work has escaped attention.…”

Section: Integrated Photonics Implementationmentioning

confidence: 99%

The missing link between standing- and traveling-wave resonators

et al. 2022

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Optical resonators are structures that utilize wave interference and feedback to confine light in all three dimensions. Depending on the feedback mechanism, resonators can support either standing- or traveling-wave modes. Over the years, the distinction between these two different types of modes has become so prevalent that nowadays it is one of the main characteristics for classifying optical resonators. Here, we show that an intermediate link between these two rather different groups exists. In particular, we introduce a new class of photonic resonators that supports a hybrid optical mode, i.e. at one location along the resonator the electromagnetic fields associated with the mode feature a purely standing-wave pattern, while at a different location, the fields of the same mode represent a pure traveling wave. The proposed concept is general and can be implemented using chip-scale photonics as well as free-space optics. Moreover, it can be extended to other wave phenomena such as microwaves and acoustics.

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Section: Integrated Photonics Implementationmentioning

confidence: 99%

The missing link between standing- and traveling-wave resonators

et al. 2022

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“…The SIP is an exceptional point degeneracy (EPD) of order three occurring in multimode waveguides without loss and gain. [2][3][4][5] While other waveguide geometries have been found to support the stationary inflection point (SIP), [6][7][8] the two SIP geometries investigated here are those in Refs. 3, 5 with their finite length structures shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Impact of waveguide imperfections on lasing near a stationary inflection point

Furman,

Herrero-Parareda,

Thompson

et al. 2023

Active Photonic Platforms (APP) 2023

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We investigate the effect of fabrication tolerances on photonic multimode waveguides operating in the vicinity of a third-order exceptional point degeneracy (EPD), known as a stationary inflection point (SIP). An EPD is a point in the parameter space where two or more Bloch eigenmodes coalesce in an infinite periodic waveguide, and at an SIP three modes coalesce to form the frozen mode. Waveguides operating near an SIP exhibit slow-light behavior in finite-length waveguides with anomalous cubic scaling of the group delay with waveguide length. The frozen mode facilitates stronger light-matter interactions in active media, resulting in a significant increase in the effective gain within the cavity. However, systems operating near an EPD are also exceptionally sensitive to fabrication deviations. In this work, we explore wave propagation and the impact of various fabrication imperfections in analytic models and in fabricated photonic chips for three mirrorless devices operating near an SIP. To advance the concept of the SIP laser, we also analyze how the addition of gain and loss affects the SIP performance. Our results show that while minor deviations from the ideal parameters can prevent perfect mode coalescence at the EPD, the frozen mode remains resilient to small perturbations and a significant degree of mode degeneracy prevails. These findings provide critical insights into the design and fabrication of passive and active photonic devices operating near high-order EPDs, paving the way for their practical implementation in a wide range of applications.

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“…Considerable efforts are required to design an EPD system, and several methods have been proposed for achieving EPD. Those approaches are based on: (i) non-Hermitian parity-time (PT) symmetric coupled systems with balanced loss and gain [10,11,12]; (ii) lossless and gainless structures associated with a stationary inflection point (SIP) and degenerate band edge (DBE) [13,14,15,16,17]; (iii) coupled resonators [18,19,20]; and (iv) time-varying systems [21,22,23,24]. Additionally, the EPD is investigated in a nonreciprocal circuit consisting of two LC resonators without gain and loss coupled via a nonreciprocal element, i.e., a gyrator [25,26,27,28,29].…”

Section: Introductionmentioning

confidence: 99%

Two resonators with negative and positive reactive components to achieve an exceptional point of degeneracy

Rouhi

Nikzamir

Figotin

et al. 2022

2022 Sixteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials)

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An exceptional point of degeneracy (EPD) occurs when both the eigenvalues and the corresponding eigenvectors of a square matrix coincide and the matrix has a nontrivial Jordan block structure. It is not easy to achieve an EPD exactly. In our prior studies, we synthesized simple conservative (lossless) circuits with evolution matrices featuring EPDs by using two LC loops coupled by a gyrator. In this paper, we advance even a simpler circuit with an EPD consisting of only two LC loops with one capacitor shared. Consequently, this circuit involves only four elements and it is perfectly reciprocal. The shared capacitance and parallel inductance are negative with values determined by explicit formulas which lead to EPD. This circuit can have the same Jordan canonical form as the nonreciprocal circuit we introduced before. This implies that the Jordan canonical form does not necessarily manifest systems' nonreciprocity. It is natural to ask how nonreciprocity is manifested in the system's spectral data. Our analysis of this issue shows that nonreciprocity is manifested explicitly in: (i) the circuit Lagrangian and (ii) the breakdown of certain symmetries in the set of eigenmodes. All our significant theoretical findings were thoroughly tested and confirmed by extensive numerical simulations using commercial circuit simulator software.

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Frozen Mode in an Asymmetric Serpentine Optical Waveguide

Cited by 12 publications

References 29 publications

The missing link between standing- and traveling-wave resonators

The missing link between standing- and traveling-wave resonators

Impact of waveguide imperfections on lasing near a stationary inflection point

Two resonators with negative and positive reactive components to achieve an exceptional point of degeneracy

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