arXiv subjects

Kenichi Komagata

Publications and source records attributed to Kenichi Komagata.

5 recordsLinked to original sources

arXiv2022

Protected generation of dissipative Kerr solitons in supermodes of coupled optical microresonators

The driven-dissipative photonic dimer comprised of two evanescently coupled high-Q microresonators is a fundamental element of multimode soliton lattices. It has demonstrated a variety of emergent nonlinear phenomena including supermode soliton generation, symmetry breaking, and soliton hopping. In this article, we present another aspect of dissipative soliton generation in coupled resonators, revealing the advantages of this system over conventional single resonator platforms. Namely, we show that the accessibility of solitons drastically varies for symmetric and antisymmetric supermode families of the dimer. Linear measurements reveal that the coupling between transverse modes, which gives rise to avoided mode crossings, can be almost completely suppressed. We explain the origin of this phenomenon and show its crucial influence on the dissipative Kerr soliton formation process in lattices of coupled high-Q resonators of any type. Choosing a particular example of the topological Su-Schrieffer-Heeger model, we demonstrate how the edge state can be protected from the interaction with higher-order modes, allowing for the formation of topological Kerr solitons.

physics.optics↗

arXiv2022

Dissipative structures in topological lattices of nonlinear optical resonators

We theoretically study the dynamics and spatio-temporal pattern formation of driven lattices of nonlinear optical microresonators and analyze the formation of dissipative structures, in particular dissipative Kerr solitons. We consider both equally coupled one-dimensional chains, as well as the topological Su-Schrieffer-Heeger model. We show the complexity of the four-wave mixing pathways arising in these systems with the increasing dimensionality due to the combined spatial and synthetic frequency dimension of each resonator, and show that it can be modeled using a two-dimensional variant of the Lugiato-Lefever equation. We demonstrate the existence of two fundamentally different dynamical regimes in one-dimensional chains - elliptic and hyperbolic - inherent to the system. In the elliptic regime, we generate hexagonal patterns and a two-dimensional dissipative Kerr soliton corresponding to the global spatio-temporal mode-locking and discuss its similarity to edge-state solitons in the two-dimensional Haldane topological lattice. We find that the presence of the second dimension leads to the observation of regularized wave collapse. Furthermore, we study similarities and differences between a one-dimensional topological lattice and a single cavity and analyze nonlinearly induced edge-to-bulk scattering in the Su-Schrieffer-Heeger model. Moreover, we show that soliton formation can both be impaired in trivial but, importantly, also topologically protected bands due to nonlinear bulk edge scattering.

physics.optics↗

arXiv2021

Dissipative Kerr solitons in a photonic dimer on both sides of exceptional point

Exceptional points are a ubiquitous concept widely present in driven-dissipative coupled systems described by a non-Hermitian Hamiltonian. It is characterized by the degeneracy of the Hamiltonian's eigenvalues and coalescence of corresponding eigenvectors. Recent developments demonstrated that exceptional points can play an important role in photonics. However, to date, exceptional points have been extensively examined in the systems supporting only a few optical modes, thereby leaving the observation of collective (multimode) effects outside of the scope of study. In the present paper, we analyze the role of exceptional points in nonlinear multimode photonics. Specifically, we provide insights into complex nonlinear dynamics arising in a continuous wave-driven pair of strongly coupled nonlinear micro-resonators (i.e. a nonlinear photonic dimer) operating in the multimode regime. Investigating this system, which is known to possess exceptional points, we find two fundamentally different nonlinear regimes of operation corresponding to effective parity-time symmetric and broken parity-time symmetry states. We demonstrate that the photonic dimer can be critically coupled to a bus waveguide, thereby, providing an efficient generation of the dissipative Kerr solitons on both sides of the exceptional point. The parity-time symmetric case, which corresponds to a pair of symmetrically split resonances, has been recently shown to exhibit a variety of emergent phenomena including gear soliton generation, symmetry breaking, and soliton hopping. Dissipative solitons generation in the parity-time symmetry broken case - leading to the dissipation splitting - up to now remains unexplored.

physics.optics↗

arXiv2020

Emergent Nonlinear Phenomena in a Driven Dissipative Photonic Dimer

Emergent phenomena are ubiquitous in nature and refer to spatial, temporal, or spatiotemporal pattern formation in complex nonlinear systems driven out of equilibrium that is not contained in the microscopic descriptions at the single-particle level. Examples range from novel phases of matter in both quantum and classical many-body systems, to galaxy formation or neural dynamics. Two characteristic phenomena are length scales that exceed the characteristic interaction length and spontaneous symmetry breaking. Recent advances in integrated photonics indicate that the study of emergent phenomena is possible in complex coupled nonlinear optical systems. Here we demonstrate that out-of-equilibrium driving of a strongly coupled ("dimer") pair of photonic integrated Kerr microresonators, which at the "single-particle" (i.e. individual resonator) level generate well understood dissipative Kerr solitons, exhibit emergent nonlinear phenomena. By exploring the dimer phase diagram, we find unexpected and therefore unpredicted regimes of soliton hopping, spontaneous symmetry breaking, and periodically emerging (in)commensurate dispersive waves. These phenomena are not included in the single-particle description and related to the parametric frequency conversion between hybridized supermodes. Moreover, by controlling supermode hybridization electrically, we achieve wide tunability of spectral interference patterns between dimer solitons and dispersive waves. Our findings provide the first critical step towards the study of emergent nonlinear phenomena in soliton networks and multimode lattices.

nlin.PS↗

arXiv2018

Efficient quantum algorithms for $GHZ$ and $W$ states, and implementation on the IBM quantum computer

We propose efficient algorithms with logarithmic step complexities for the generation of entangled $GHZ_N$ and $W_N$ states useful for quantum networks, and we demonstrate an implementation on the IBM quantum computer up to $N=16$. Improved quality is then investigated using full quantum tomography for low-$N$ GHZ and W states. This is completed by parity oscillations and histogram distance for large $N$ GHZ and W states respectively. We are capable to robustly build states with about twice the number of quantum bits which were previously achieved. Finally we attempt quantum error correction on GHZ using recent schemes proposed in the literature, but with the present amount of decoherence they prove detrimental.

quant-ph↗