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Journal ArticleDOI

Semianalytical method to study silicon slot waveguides for optical sensing application

01 Oct 2013-Optical Engineering (International Society for Optics and Photonics)-Vol. 52, Iss: 10, pp 107102-107102
TL;DR: In this article, an effective index based matrix method was used to analyze high-index contrast slab and slot optical waveguides, and the results were compared with results obtained from numerical techniques like finite element method, finite-difference time-domain, and beam propagation method.
Abstract: High-index contrast slab and slot optical waveguides have a high index variation both along the lateral and vertical interfaces and are usually analyzed numerically, requiring large computer memory and time. In this article, their analysis is done semianalytically using an effective-index based matrix method. This method, which is computationally very fast, was earlier used successfully for low-index profile waveguide structures only and is now suitably modified for use in high-index contrast structures. The electric field profile of the waveguide structures is plotted and the effective refractive index at different wavelengths is calculated. The results are compared with results obtained from numerical techniques like finite element method, finite-difference time-domain, and beam propagation method and they match very well. The dependence of their different optical characteristics with the waveguide parameters is also studied. These studies will help in obtaining improved sensitivity of slot waveguides for sensing applications.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors investigated a modification by adding a Si layer beneath a segmented slot waveguide (SSW) and optimizing the hybrid SSW as the core of a sensor to determine the sensor features in terms of the frequency response and sensitivity.
Abstract: Integrated electric-field (E-field) sensors are commonly used devices in E-field sensing. However, distortion in the modulated signal due to high half-voltage ( V π ) and obtaining a low-frequency response are challenging issues in low-frequency AC E-field sensors. The aim of this study is to investigate a modification by adding a Si layer beneath a segmented slot waveguide (SSW) and optimizing the hybrid SSW as the core of a sensor to determine the sensor features in terms of the frequency response and sensitivity. The results of reducing the Si-layer thickness and segment width with high periodicity revealed a high modulation efficiency for very low-frequency AC E-field sensors and simultaneously expanded the minimum limit of detection by incorporating sensors in very small AC E-fields. This study validated the feasibility and efficiency of using a hybrid SSW as the core of highly sensitive low-frequency AC E-field sensors.

6 citations


Cites methods from "Semianalytical method to study sili..."

  • ...tions of the TE0 mode, which is important in analyzing the hybrid SSW using the transverse E-field amplitude along the x-axis.(44) By following the same method, the con-...

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Posted Content
19 Nov 2019
TL;DR: In this paper, the authors explored the impact of waveguide design in photon collection efficiency and indistinguishability of single photon emitters embedded in photonic integrated circuits and proposed an analytical model based in the Green dyadic of the Helmholtz equation for different geometries of the waveguide.
Abstract: This work explores the impact of waveguide design in photon collection efficiency and indistinguishability of single photon emitters embedded in photonic integrated circuits. Transition Metal Dichalcogenides (TMDC) materials have been selected as single photon emitters because their prominent properties for single photon emission: their giant oscillator strength promotes a stronger Purcell effect and their short exciton lifetimes enhances the indistinguishability of photons. We have calculated the photon extraction efficiency and the indistinguishability of a TMDC point-source of photons with arbitrary orientation embedded at an arbitrary location within a SiN waveguide. For the calculation we propose an analytical model based in the Green dyadic of the Helmholtz equation for different geometries of the waveguide, position of the source and orientation. Calculations have been numerically evaluated through finite-difference time-domain (FDTD) simulations showing consistent results. We have found a maximum coupling up to 81% to the fundamental mode when the quantum emitter is placed in the centre of the waveguide and a maximum indistinguishability of 81% when the emitter is placed 10 nm away from the edge of the waveguide. The results help for a better understanding of the coupling of quantum emitters to nanophotonic devices and photonic integrated circuits (PICs).

6 citations


Cites background from "Semianalytical method to study sili..."

  • ...Due to the index contrast between air and waveguide the electric field feels a strong discontinuity at the interface with an amount comparable to the square of the index ratio at the interface [34]....

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Journal ArticleDOI
TL;DR: In this article, an optimized segmented slot waveguide was used as the core of a sensor to determine the sensor features that produce useful frequency responses and sensitivity for low-frequency alternating-current (AC) electric-field sensors.
Abstract: The use of integrated waveguide modulators is a common technique in electric-field sensing. However, the distortion in the modulated signal caused by high half-voltage Vπ and the difficulty in obtaining low-frequency responses are challenging issues for the use of low-frequency alternating-current (AC) electric-field sensors. This study investigates the use of an optimized segmented slot waveguide as the core of a sensor to determine the sensor features that produce useful frequency responses and sensitivity. The segmented slot waveguide is optimized in terms of periodicity and segment width to produce low Vπ and electrical bandwidth before testing the sensor sensitivity. The results show that reducing the segment width achieves a low Vπ of 0.32 V and a very low electrical bandwidth of 4.3 kHz. Our study provides evidence of the feasibility of using a segmented slot waveguide as the primary element for highly sensitive, low-frequency AC electric-field sensors.

6 citations


Cites methods from "Semianalytical method to study sili..."

  • ...The overlap integral factor (Γ) was studied for a slot waveguide through the transverse E-field amplitude along the x-axis.(26,27) In this study, we followed the same method to determine the confinement of the TE0 mode inside the slot region and to detect the effect of using different segmented waveguide dimensions (periodicity and segment width) on the horizontal aggregation reflection that reconcentrates the light beam in the overlap area....

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Journal ArticleDOI
TL;DR: In this article, the authors developed an analytical model that uses the Green's Dyadic of a 3D unbounded rectangular waveguide to calculate the coupling and the indistinguishability of an ideal point-source quantum emitter coupled to a photonic waveguide depending on its orientation and position.
Abstract: One of the main steps towards large-scale quantum photonics consists of the integration of single photon sources (SPS) with photonic integrated circuits (PICs). For that purpose, the PICs should offer an efficient light coupling and a high preservation of the indistinguishability of photons. Therefore, optimization of the indistinguishability through waveguide design is especially relevant. In this work we have developed an analytical model that uses the Green’s Dyadic of a 3D unbounded rectangular waveguide to calculate the coupling and the indistinguishability of an ideal point-source quantum emitter coupled to a photonic waveguide depending on its orientation and position. The model has been numerically evaluated through finite-difference time-domain (FDTD) simulations showing consistent results. The maximum coupling is achieved when the emitter is embedded in the center of the waveguide but somewhat surprisingly the maximum indistinguishability appears when the emitter is placed at the edge of the waveguide where the electric field is stronger due to the surface discontinuity.

5 citations

Journal ArticleDOI
TL;DR: In this article, a compact, dielectric-metal-dielectric surface plasmon polariton (SPP) waveguide is designed that can have propagation lengths as high as several thousand microns.
Abstract: A compact, dielectric–metal–dielectric surface plasmon polariton (SPP) waveguide is designed that can have propagation lengths as high as several thousand microns. The dielectric layers surrounding the metal waveguide are actually periodic layers of different nanometer-sized dielectric pairs. By proper selection of the surrounding layer widths, a device with a controllable effective index and increased compactness can be designed. It can have a propagation loss

3 citations


Cites methods from "Semianalytical method to study sili..."

  • ...Here, the Lorentzian peak is obtained by calculating the excitation efficiency of the waveguide structure using the matrix approach.(30,31) The propagation loss is calculated from the FWHM of the Lorentzian peak as is done in Ref....

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References
More filters
Journal ArticleDOI
TL;DR: All-optical logic in a micron-size silicon ring resonator based on the free-carrier dispersion effect in silicon is demonstrated and the free -carrier-lifetime-limited bit-rate can be significantly improved by active carrier extraction.
Abstract: We demonstrate all-optical logic in a micron-size silicon ring resonator based on the free-carrier dispersion effect in silicon. We show AND and NAND operation at 310 Mbit/s with ∼10-dB extinction ratio. The free-carrier-lifetime-limited bit-rate can be significantly improved by active carrier extraction.

465 citations


Additional excerpts

  • ...Ri 1⁄4 n 2 i cos θi − n(2)iþ1 cos θiþ1 n(2)i cos θi þ n(2)iþ1 cos θiþ1 ; (5)...

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Journal ArticleDOI
TL;DR: Values up to gamma=7 x 10(6)/(W km) for the nonlinear parameter are feasible if silicon-on-insulator based strip and slot waveguides are properly designed, and this enables ultrafast all-optical signal processing with nonresonant compact devices.
Abstract: Values up to gamma=7 x 10(6)/(W km) for the nonlinear parameter are feasible if silicon-on-insulator based strip and slot waveguides are properly designed This is more than three orders of magnitude larger than for state-of-the-art highly nonlinear fibers, and it enables ultrafast all-optical signal processing with nonresonant compact devices At lambda=155 microm we provide universal design curves for strip and slot waveguides which are covered with different linear and nonlinear materials, and we calculate the resulting maximum gamma

395 citations

Journal ArticleDOI
TL;DR: An experimental demonstration of an integrated biochemical sensor based on a slot-waveguide microring resonator that detects a minimal refractive index variation of 2x10(-4) RIU.
Abstract: We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguide microring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 μm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n=1.33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2×10−4 RIU.

378 citations

Journal ArticleDOI
TL;DR: A theoretical investigation of silicon-on-insulator nanometer slot waveguides for highly sensitive and compact chemical and biochemical integrated optical sensing is proposed.
Abstract: A theoretical investigation of silicon-on-insulator nanometer slot waveguides for highly sensitive and compact chemical and biochemical integrated optical sensing is proposed. Slot guiding structures enabling high optical confinement in a low-index very small region are demonstrated to be very sensitive to either cover medium refractive index change or deposited receptor layer thickness increase. Modal and confinement properties of slot waveguides have been investigated, considering also the influence of fabrication tolerances. Waveguide sensitivity has been calculated and compared with that exhibited by other silicon nanometer guiding structures, such as rib or wire waveguides, or with experimental values in literature.

357 citations


Additional excerpts

  • ...Ti 1⁄4 2n 2 i cos θi n(2)i cos θiþ1 þ n(2)iþ1 cos θi ; (6)...

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Journal ArticleDOI
TL;DR: Refractive index differences as small as 10-4 between air and acetylene at varying pressures in the near-IR are measured to detect acetylene gas on a silicon chip using photonic microcavities and a chip-scale gas cell.
Abstract: We demonstrate a chip-scale photonic system for the room-temperature detection of gas composition and pressure using a slotted silicon microring resonator. We measure shifts in the resonance wavelength due to the presence and pressure of acetylene gas and resolve differences in the refractive index as small as 10-4 in the near-IR. The observed sensitivity of this device (enhanced due to the slot-waveguide geometry) agrees with the expected value of 490 nm/refractive index unit.

321 citations