Coupled mode analysis of micro-disk resonators with an asymmetric-index-profile coupling region

Arlotti, Clément; Almuneau, Guilhem; Gauthier-Lafaye, Olivier; Calvez, S.

doi:10.1117/12.2250157

Cited by 3 publications

(7 citation statements)

References 14 publications

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“…As it will be described in full in section V, the behavior in the evanescent coupling section of length L (see Fig. 1) is treated using the complete Coupled-Mode Theory (CMT) as in references [18] and [27]. The assumption made here is that bothf the resonator and access waveguides are each taken to only support one single transverse mode.…”

Section: Model Of the Waveguide-coupled Resonatorsmentioning

confidence: 99%

Coupled-Mode Analysis of Vertically Coupled AlGaAs/AlOx Microdisk Resonators

Arlotti

Lafleur

Larrue

et al. 2018

IEEE J. Quantum Electron.

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This article reports the experimental and theoretical assessments of the optical characteristics of recently-introduced vertically-coupled microdisk resonators made by selective oxidation of AlGaAs multilayer structures. Experimental measurements show that the Q-factors are in the 10 3 to 10 4 range for diameters ranging from 75 to 300 µm. To establish the origins of this limited performance a coupled-mode-theory-based model of the single-access-waveguide-coupled resonator system was developed. It includes features which are specific to oxide-based vertically-coupled resonators, namely losses towards the slab waveguide lying under the resonator and a coupling region with an asymmetric and multilayer structure. Setting this simulation tool required the proposal and validation of a general criterion to select an appropriate set of decomposition permittivity profiles to be able to accurately model the characteristics of these more complex couplers using the coupled-mode-theory approach. This theoretical development is generic and can be now deployed to simulate any device which includes multi-waveguide couplers with arbitrary piece-wise-constant profile of the dielectric permittivity. Exploiting this particular development and experimental measurements of the disk sidewall roughness and of the coupling lengths, the calculated and experimental Q-factors are found to be in good agreement and allow establishing that the current performance is limited by the scattering losses and the slab-leakage losses for small-and large-diameter devices respectively.

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Section: Model Of the Waveguide-coupled Resonatorsmentioning

confidence: 99%

Coupled-Mode Analysis of Vertically Coupled AlGaAs/AlOx Microdisk Resonators

Arlotti

Lafleur

Larrue

et al. 2018

IEEE J. Quantum Electron.

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“…Noting that a, and K(λ)=κa(λ)κb(λ) are independent variables, expanding equation (12b) leads to: (15) With 16and (17) Assuming that the resonator losses are wavelength-independent, the achromatic critically-coupled designs are solutions of (13) and of the simplified equation:…”

Section: Figmentioning

confidence: 99%

“…to be phase mismatched (PMM). Equations (16) and (17) can then be approximated by: An achromatic critically-coupled design whose coupler length is L~(2m±1)Lπ(λ0)/2 simultaneously verifies equations (18), (22), (23) and presents an achromatic power-coupling efficiency as the evaluation of equation 24shows that:…”

Section: Figmentioning

confidence: 99%

“…According to the experimentally-validated models of references [11]- [13], vertically-coupled WGM resonators with single transverse mode waveguides can be efficiently modelled using CMT considering the coupling region as being made of two parallel one-dimensional slab waveguides whose length, L, depends on the waveguides dimensions and positions. Following simple geometric considerations [17], for center-aligned waveguides as assumed here,…”

Section: B Resonator Design and Characteristicsmentioning

confidence: 99%

“…3a). As an integral part of the above-mentioned approximation, the complete set of mode overlap coefficients is calculated by the one-dimensional numerical integration along the vertical axis of the TE-polarized guided mode profiles of the constitutive (resonator and access) decomposition waveguides defined according to the criterion detailed in [17]. The accuracy of this approximation will obviously improve as the considered waveguides resemble slab-like waveguides i.e.…”

Section: B Resonator Design and Characteristicsmentioning

confidence: 99%

See 2 more Smart Citations

Achromatic critically coupled racetrack resonators

Arlotti¹,

Gauthier-Lafaye²,

Monmayrant³

et al. 2017

J. Opt. Soc. Am. B

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In this paper, we investigate the spectral response of whispering-gallery-mode (WGM) resonators coupled to their access waveguide with a view to design their constitutive waveguides to promote critical-coupling over a wide spectral range and thereby facilitate their use for high-sensitivity sensing or nonlinear frequency conversion applications. The carried-out theoretical analysis is based on the universal response functions of singlemode and unidirectional devices. A coupled-mode treatment of the coupling region enables to derive two sets of favorable designs. The identified resonator/access waveguide systems exploit waveguides with mismatched propagation constants forming a coupling section exhibiting either an achromatic beat-length or an achromatic power-transfer coefficient. This generic model is followed by a numerical case study of vertically-coupled Si3N4 racetrack resonators. The conventional (quasi-)phase-matched configuration, treated as a reference case, is shown to display a critical-coupling bandwidth of 23 nm at a wavelength of 1550nm, whereas the proposed new designs demonstrate critical bandwidths larger than 330nm, i.e. exhibit bandwidths enhanced by more than one order of magnitude.

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Silicon-Based Group-IV O-E-O Devices for Gain, Logic, and Wavelength Conversion

et al. 2020

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Using the strip-guided “manufacturable” SOI/GeSn group-IV integrated-photonics platform operating at 1550 nm, we propose an optical-to-electrical-to-optical (O-E-O) device that can work either as an amplifierless optical repeater with gain, as a linear-optics wavelength-converter repeater, or as a new “optical–optical” logic (OOL) gate. An interconnected array of such linear-optics gates performs complicated digital-logic functions. The OEO comprises a photodetector (PD), an electro-optical modulator (EOM), and an electrical biasing-and-interconnect circuit. A digitally modulated optical signal is sent into a waveguided photoconductive GeSn PIN PD whose electrical output is compatible with the electrical input of a resonant bus-coupled Si PN-depletion microdisk EOM modulating a CW optical input beam. Our self-consistent physical model takes into account N and P doping effects. Assuming a peak optical input power of 0.5 mW and 3 V DC bias, our 1.55 μm simulations predict successful repeater-converter operation at 6.5 GHz (13 Gbit/s) and successful OOL functioning at 4.7 GHz (9.4 Gbit/s), with 12-to-16 dB extinction ratio and switching energy in the 5.8 to 9.6 fJ/bit range. A further increase of the OOL bit rate to 14 Gbit/s is available at the expense of an increased optical signal power.

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Coupled mode analysis of micro-disk resonators with an asymmetric-index-profile coupling region

Cited by 3 publications

References 14 publications

Coupled-Mode Analysis of Vertically Coupled AlGaAs/AlOx Microdisk Resonators

Coupled-Mode Analysis of Vertically Coupled AlGaAs/AlOx Microdisk Resonators

Achromatic critically coupled racetrack resonators

Silicon-Based Group-IV O-E-O Devices for Gain, Logic, and Wavelength Conversion

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