Graded index photonic crystals

Kurt, Hamza; Citrin, D. S.

doi:10.1364/oe.15.001240

Cited by 131 publications

(64 citation statements)

References 21 publications

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“…Although in principle anisotropic materials, such as SiC, can be used in silicon photonics, TO requires in general a gradient anisotropy, which is much more complex to achieve. Note that one could also use photonic crystals [9][10][11][12] or grooves 13,14 to tailor the index and anisotropy, however these discrete structures result in additional field scattering and inter-mode coupling due to the finite wavelength/period ratio (typically around 10:1). Instead, we use a grayscale-lithography technique described below that produces smooth gradients but is limited to mostly isotropic effective indices.…”

Section: Resultsmentioning

confidence: 99%

On-chip transformation optics for multimode waveguide bends

et al. 2012

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Current optical communication systems rely almost exclusively on multimode fibres for short-and medium-haul transmissions, and are now expanding into the long-haul arena. Ultra-high bandwidth applications are the main drive for this expansion, based on the ability to spatially multiplex data channels in multimode systems. Integrated photonics, on the other hand, although largely responsible for today's telecommunications, continues to operate almost strictly in the single-mode regime. This is because multimode waveguides cannot be compactly routed on-chip without significant inter-mode coupling, which impairs their data rate and prevents the use of modal multiplexing. Here we propose a platform for on-chip multimode devices with minimal inter-mode coupling, opening up the possibilities for integrated multimode optics. Our work combines a novel theoretical approach-large-scale inverse design of transformation optics to maximize performance within fabrication constraints-with unique grayscale-lithography fabrication of an exemplary device: a low-crosstalk multimode waveguide bend.

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Section: Resultsmentioning

confidence: 99%

On-chip transformation optics for multimode waveguide bends

et al. 2012

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“…In the relatively early studies, [19][20][21][22] the PCs were usually composed of an uniform structure with various geometrical shapes, and the same physical limitations as for conventional optical lenses were therefore observed. Later, analogously to the studies in optics, 23 gradient-index (GRIN) PCs were proposed, especially for waves at low frequency, on the first acoustic band. 24,25 To now the focusing achievements for waves with different polarizations have been investigated.…”

Section: Introductionmentioning

confidence: 93%

Beam paths of flexural Lamb waves at high frequency in the first band within phononic crystal-based acoustic lenses

2014

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International audienceThis work deals with an analytical and numerical study of the focusing of the lowest order anti-symmetric Lamb wave in gradient index phononic crystals. Computing the ray trajectories of the elastic beam allowed us to analyze the lateral dimensions and shape of the focus, either in the inner or behind the phononic crystal-based acoustic lenses, for frequencies within a broad range in the first band. We analyzed and discussed the focus-ing behaviors inside the acoustic lenses where the focalization at sub-wavelength scale was achieved. The focalization behind the gradient index phononic crystal is shown to be efficient as well: we report on FMHM = 0.63λ at 11MHz

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“…Gradient variations introduced in the lattice period, filling factor, and dielectric constant of these periodic media (referred as Gradient Index Photonic Crystals (GRIN PC) [6]) can provide efficient light molding applications such as spatial beam compression [7,8], effective control over light propagation [9], optical absorbers [10], directional cloaking [11] etc.…”

Section: Introductionmentioning

confidence: 99%

Spatial Beam Compression and Effective Beam Injection Using Triangular Gradient Index Profile Photonic Crystals

Yogesh¹,

Subramanian²

2012

PIER

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Abstract-Spatial beam compression of an electromagnetic wave is one of the fundamental techniques employed in microwaves and optics. As there are many ways to achieve this task using the combination of prisms and lenses, recent research suggests the parabolic gradient index photonic crystals (GRIN PC) for the design of spatial beam compressor owing to its functionalities. However, the fabrication of a graded media with the parabolic profile is a difficult challenge in practical realization. As an alternative, present work attempts this problem with respect to the triangular gradient index profile. The performance and aspects of the beam compression are investigated experimentally using the pillar type GRIN PC at the microwave length-scales. The utility of the device for an effective beam injection to the photonic-waveguide component is further demonstrated experimentally.

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Graded index photonic crystals

Cited by 131 publications

References 21 publications

On-chip transformation optics for multimode waveguide bends

On-chip transformation optics for multimode waveguide bends

Beam paths of flexural Lamb waves at high frequency in the first band within phononic crystal-based acoustic lenses

Spatial Beam Compression and Effective Beam Injection Using Triangular Gradient Index Profile Photonic Crystals

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