Oscillatory Vertical Coupling between a Whispering-Gallery Resonator and a Bus Waveguide

Ghulinyan, Mher; Ramiro‐Manzano, Fernando; Prtljaga, N.; Guider, R.; Carusotto, Iacopo; Pitanti, Alessandro; Pucker, G.; Pavesi, L.

doi:10.1103/physrevlett.110.163901

Cited by 41 publications

(32 citation statements)

References 21 publications

(30 reference statements)

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“…Since light is usually coupled in and out of the resonators by evanescent coupling, the preferred technique to address the latter challenge relies on using a vertical integration scheme where the access waveguide lies (typically) below the resonator. Indeed, this approach offers greater fabrication tolerances and enables different materials to be used for the resonator and its access waveguides [4]. However, it generally suffers from complex fabrication procedures involving either a demanding planarization of the coupling layer to a set thickness [5]- [7] or a critical substrate transfer to allow both sides of a few-micrometer-thick epilayer to be processed [8].…”

Section: Introductionmentioning

confidence: 99%

Vertically Coupled Microdisk Resonators Using AlGaAs/AlOx Technology

Calvez

Lafleur

Larrue

et al. 2015

IEEE Photon. Technol. Lett.

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In this letter, we report the first experimental demonstration of microdisk resonators that are vertically coupled to their buried access waveguides on III-V semiconductor epitaxial structures using an original fabrication process. The here-proposed and validated three-dimensional integration scheme exploits selective lateral thermal oxidation of aluminiumrich AlGaAs layers. Compared with the previously reported processing techniques, this new scheme is simpler as it does not require any planarization or substrate transfer steps. As a proofof-principle demonstration of this approach, 250-µm diameter microdisk devices exhibiting quality factor reaching ∼8500 have been successfully fabricated.

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Section: Introductionmentioning

confidence: 99%

Vertically Coupled Microdisk Resonators Using AlGaAs/AlOx Technology

Calvez

Lafleur

Larrue

et al. 2015

IEEE Photon. Technol. Lett.

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“…In the context of integrated planar microresonator devices, design rules [26,27] and optimized coupler geometries [17,28,29] have been reported. However, comparatively little attention has been paid to their coupler performance, especially with regard to the multi-mode nature of waveguides.…”

Section: Introductionmentioning

confidence: 99%

Coupling Ideality of Integrated Planar High-QMicroresonators

et al. 2017

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( † These authors contributed equally to this work.)Chipscale optical microresonators with integrated planar optical waveguides are useful building blocks for linear, nonlinear and quantum optical photonic devices alike. Loss reduction through improving fabrication processes has resulted in several integrated microresonator platforms attaining quality (Q) factors of several millions. Beyond improvement of quality factor, the ability to operate the microresonator with high coupling ideality in the overcoupled regime is of central importance. In this regime the dominant source of loss constitutes the coupling to a single, desired output channel, which is particularly important not only for quantum optical applications such as the generation of squeezed light and correlated photon pairs but also for linear and nonlinear photonics. However to date, the coupling ideality in integrated photonic microresonator is not well understood, in particular design-dependent losses and their impact on the regime of high ideality. Here we investigate design-dependent parasitic losses, described by the coupling ideality, of the commonly employed microresonator design consisting of a microring resonator waveguide side-coupled to a straight bus waveguide, a system which is not properly described by the conventional input-output theory of open systems, due to the presence of higher-order modes. By systematic characterization of multi-mode high-Q silicon nitride microresonator devices, we show that this design can suffer from low coupling ideality. By performing 3D simulations, we identify the coupling to higher-order bus waveguide modes as the dominant origin of parasitic losses which lead to the low coupling ideality. Using suitably designed bus waveguides, parasitic losses are mitigated with a nearly unity ideality and strong overcoupling (i.e. a ratio of external coupling to internal resonator loss rate > 9), are demonstrated. Moreover, we find that different resonator modes can exchange power through the coupler, which therefore constitutes a mechanism that induces modal coupling, a phenomenon known to distort resonator dispersion properties. Our results demonstrate the potential for significant performance improvements of integrated planar microresonators for applications in quantum optics and nonlinear photonics, achievable by optimized coupler designs.

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“…The exponential term is a natural choice when dealing with a logarithmic scale factor. Moreover, this Hamiltonian has experimental potential [29][30][31]. First, we look at the single-system case.…”

Section: Logarithmic Scale-factormentioning

confidence: 99%

Optomechanical Analogy for Toy Cosmology with Quantized Scale Factor

Smiga

2017

Entropy

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Abstract:The simplest cosmology-the Friedmann-Robertson-Walker-Lemaître (FRW) modeldescribes a spatially homogeneous and isotropic universe where the scale factor is the only dynamical parameter. Here we consider how quantized electromagnetic fields become entangled with the scale factor in a toy version of the FRW model. A system consisting of a photon, source, and detector is described in such a universe, and we find that the detection of a redshifted photon by the detector system constrains possible scale factor superpositions. Thus, measuring the redshift of the photon is equivalent to a weak measurement of the underlying cosmology. We also consider a potential optomechanical analogy system that would enable experimental exploration of these concepts. The analogy focuses on the effects of photon redshift measurement as a quantum back-action on metric variables, where the position of a movable mirror plays the role of the scale factor. By working in the rotating frame, an effective Hubble equation can be simulated with a simple free moving mirror.

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Oscillatory Vertical Coupling between a Whispering-Gallery Resonator and a Bus Waveguide

Cited by 41 publications

References 21 publications

Vertically Coupled Microdisk Resonators Using AlGaAs/AlOx Technology

Vertically Coupled Microdisk Resonators Using AlGaAs/AlOx Technology

Coupling Ideality of Integrated Planar High-QMicroresonators

Optomechanical Analogy for Toy Cosmology with Quantized Scale Factor

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