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Diffraction grating

About: Diffraction grating is a research topic. Over the lifetime, 24884 publications have been published within this topic receiving 372437 citations. The topic is also known as: grating.


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Journal ArticleDOI
TL;DR: Experimental measurements indicate a propagation loss as low as 2.1 dB/cm for subwavelength grating waveguide with negligible polarization and wavelength dependent loss, which compares favourably to conventional microphotonic silicon waveguides.
Abstract: We report on the experimental demonstration and analysis of a new waveguide principle using subwavelength gratings. Unlike other periodic waveguides such as line-defects in a 2D photonic crystal lattice, a subwavelength grating waveguide confines the light as a conventional index-guided structure and does not exhibit optically resonant behaviour. Subwavelength grating waveguides in silicon-on-insulator are fabricated with a single etch step and allow for flexible control of the effective refractive index of the waveguide core simply by lithographic patterning. Experimental measurements indicate a propagation loss as low as 2.1 dB/cm for subwavelength grating waveguides with negligible polarization and wavelength dependent loss, which compares favourably to conventional microphotonic silicon waveguides. The measured group index is nearly constant n(g) ~1.5 over a wavelength range exceeding the telecom C-band.

288 citations

Journal ArticleDOI
TL;DR: Two experimental examples of refractive index engineering are demonstrated, namely, a microphotonic fiber-chip coupler with a coupling loss as small as -0.9dB and minimal wavelength dependence and a planar waveguide multiplexer with SWG nanostructure, which acts as a slab waveguide for light diffracted by the grating, while at the same time acting as a lateral cladding for the strip waveguide.
Abstract: We use subwavelength gratings (SWGs) to engineer the refractive index in microphotonic waveguides, including practical components such as input couplers and multiplexer circuits. This technique allows for direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6–3.5 by lithographic patterning. We demonstrate two experimental examples of refractive index engineering, namely, a microphotonic fiber-chip coupler with a coupling loss as small as −0.9dB and minimal wavelength dependence and a planar waveguide multiplexer with SWG nanostructure, which acts as a slab waveguide for light diffracted by the grating, while at the same time acting as a lateral cladding for the strip waveguide. This yields an operation bandwidth of 170nm for a device size of only ~160μm×100μm.

285 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a whole host of processes which can enhance and tailor the properties of both conventional and not-so-conventional fibre Bragg gratings, including multi-photon excitation of germanosilicate based defects with CW 244 nm light.
Abstract: Although mainstream grating writing, more often than not using single photon excitation of germanosilicate based defects with CW 244 nm light, remains the key technology for complex devices it is now being complemented by a whole host of processes which can enhance and tailor the properties of both conventional and not-so-conventional fibre Bragg gratings. Further, processes for writing of gratings in non-germanosilicate fibres have also continued to develop and include multi-photon excitation directly into the band edge of the glass. It is now possible to custom tailor a gratings property based on the application and the nature of production as well as custom tailor the grating writing process to suit the type of fibre and application. Examples and suggestions where these can benefit sensors and lasers are outlined.

282 citations

Patent
13 Jun 2001
TL;DR: An apparatus for high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is described in this paper.
Abstract: An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens A mirror is placed one focal length away from the lens and the alteration of the grating groove density, the grating input angle, the grating output angle, and/or the mirror tilt produce a change in optical group and phase delay This apparatus permits the optical group and phase delay to be scanned by scanning the angle of the mirror In other embodiments, this device permits optical delay scanning without the use of moving parts

280 citations

Journal ArticleDOI
TL;DR: In this article, the diffraction of light by periodic gratings is analyzed with a characteristic-matrix formalism based on a rigorous coupled-wave approach, and a new algorithm that remains stable for gratings of any thickness is proposed.
Abstract: Diffraction of light by periodic gratings is analyzed with a characteristic-matrix formalism based on a rigorous coupled-wave approach. This formalism is particularly convenient for modeling the diffraction by nonuniform periodic structures. In order to overcome numerical difficulties that are due to inhomogeneous eigenmodes, we propose a new algorithm that remains stable for gratings of any thickness. We obtain the stability by distinguishing in the computation the growing and the decaying inhomogeneous modes. Numerical examples and comparisons with previous results are given.

279 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202394
2022279
2021266
2020426
2019534
2018606