Characterisation of multi-mode propagation in silicon nitride slab waveguides

Jennings, Brian D.; McCloskey, David; Gough, John J.; Hoang, Tung T.; Abadía, Nicolás; Zhong, Chuan Jian; Karademir, Ertuğrul; Bradley, A. Louise; Donegan, John F.

doi:10.1088/2040-8986/19/1/015604

Cited by 6 publications

(4 citation statements)

References 33 publications

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“…Therefore, this parameter will be used to describe the broadband interference phenomenon in the next section. Methods for directly measuring and determining differences in the propagation constants Δ β can be found in the literature [42,43]. The relationship between the propagation constant and the effective refractive index is expressed as follows: βi(λ,nc)=2πNi(λ,nc)λ, after substituting in Equation (3) into Equation (6), one can derive the following: sans-serifΔϕ(λ,nc)=sans-serifΔβ(λ,nc)⋅L, where Δ β is the difference in the propagation constants for TE and TM modes: sans-serifΔβ(λ,nc)=βTE(λ,nc)−βTM(λ,nc).…”

Section: Resultsmentioning

confidence: 99%

Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides

Gut

2019

Nanomaterials

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A model and the waveguide parameters of a broadband, polymer-based slab waveguide difference interferometer is presented in this paper. The parameters were determined based on knowledge of the dispersion in the structure materials used to fabricate the waveguide. The impact of the waveguide layer thickness, propagation path length, and change in the waveguide cover refractive index on the output signal from the system was determined. It has been shown that the direction of the maximum shifting is determined by the thickness of the waveguide layer. A relationship describing the shift in the signal extrema for a change in the waveguide cover refractive index was derived. The results show that the use of a propagation constant simplifies the description of the interferometer. Polymer waveguides, although they have a small contrast in refractive indices, allow for large shifts in the maxima of the signal. The determined shifts in the output signal extrema for polymer waveguides are comparable, and these shifts are larger for some waveguide thicknesses compared to waveguides based on Si3N4.

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Section: Resultsmentioning

confidence: 99%

Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides

Gut

2019

Nanomaterials

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“…For instance, rectangular crosssection nanophotonic waveguides are well-known to support both quasi-transverse-electric (TE-like) and quasi-transversemagnetic (TM-like) modes, the number of which depends on the waveguide's width and height (46). Although orthogonality prevents copropagating modes from interfering with each other, the local phase difference between their evanescent tails causes various near-field light-matter interactions (43,(47)(48)(49)(50), including optical forces (10), to be subject to near-field mode-beating phenomena. When two co-propagating guided modes are excited, a periodic spatial modulation of the optical force field appears along the waveguide, with a characteristic beat period (43,47,49,50):…”

Section: Experimental Optical Force Modulation Via Near-field Mode Bementioning

confidence: 99%

Optical tweezing using tunable optical lattices along a few-mode silicon waveguide

Jager

Tardif

et al. 2018

Lab Chip

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Fourteen years ago, optical lattices and holographic tweezers were considered as a revolution, allowing for trapping and manipulating multiple particles at the same time using laser light. Since then, near-field optical forces have aroused tremendous interest as they enable efficient trapping of a wide range of objects, from living cells to atoms, in integrated devices. Yet, handling at will multiple objects using a guided light beam remains a challenging task for current on-chip optical trapping techniques. We demonstrate here on-chip optical trapping of dielectric microbeads and bacteria using one-dimensional optical lattices created by near-field mode beating along a few-mode silicon nanophotonic waveguide. This approach allows not only for trapping large numbers of particles in periodic trap arrays with various geometries, but also for manipulating them via diverse transport and repositioning techniques. Near-field mode-beating optical lattices may be readily implemented in lab-on-a-chip devices, addressing numerous scientific fields ranging from bio-analysis to nanoparticle processing.

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“…The dielectric waveguide consists of a 180 nm thick LPCVD deposited silicon nitride (Si3N4) core on a 2 μm thermally grown silicon dioxide (SiO2) layer on Silicon (Si-Mat). This structure can support only one transverse magnetic (TM) and one transverse electric (TE) mode at the free space wavelength of λ0 = 850 nm [22]. The evanescent coupling between the core Si3N4 (refractive index = 2.02) waveguide and the NFT occurs in the presence of another dielectric layer with a smaller index than the core, here chosen to be SiO2 (refractive index = 1.45).…”

Section: Nft Designmentioning

confidence: 99%

Effective heat dissipation in an adiabatic near-field transducer for HAMR

Zhong¹,

Flanigan²,

Abadía³

et al. 2018

Opt. Express

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To achieve a feasible heat-assisted magnetic recording (HAMR) system, a near-field transducer (NFT) is necessary to strongly focus the optical field to a lateral region measuring tens of nanometres in size. An NFT must deliver sufficient power to the recording medium as well as maintain its structural integrity. The self-heating problem in the NFT causes materials failure that leads to the degradation of the hard disk drive performance. The literature reports NFT structures with physical sizes well below 1 micron which were found to be thermo-mechanically unstable at an elevated temperature. In this paper, we demonstrate an adiabatic NFT to address the central challenge of thermal engineering for a HAMR system. The NFT is formed by an isosceles triangular gold taper plasmonic waveguide with a length of 6 µm and a height of 50 nm. Our study shows that in the full optically and thermally optimized system, the NFT efficiently extracts the incident light from the waveguide core and can improve the shape of the heating source profile for data recording. The most important insight of the thermal performance is that the recording medium can be heated up to 866 K with an input power of 8.5 mW which is above the Curie temperature of the FePt film while maintaining the temperature in the NFT at 390 K without a heat spreader. A very good thermal efficiency of 5.91 is achieved also. The proposed structure is easily fabricated and can potentially reduce the NFT deformation at a high recording temperature making it suitable for practical HAMR application.

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Characterisation of multi-mode propagation in silicon nitride slab waveguides

Cited by 6 publications

References 33 publications

Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides

Study of a Broadband Difference Interferometer Based on Low-Cost Polymer Slab Waveguides

Optical tweezing using tunable optical lattices along a few-mode silicon waveguide

Effective heat dissipation in an adiabatic near-field transducer for HAMR

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