Disorder effects in subwavelength grating metamaterial waveguides

Ortega‐Moñux, Alejandro; Čtyroký, Jiřı́; Cheben, Pavel; Schmid, Jens H.; Wang, Shurui; Molina-Fernández, Í.; Halir, Robert

doi:10.1364/oe.25.012222

Cited by 33 publications

(19 citation statements)

References 27 publications

(34 reference statements)

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“…Tab l e 1 Footprint and Performance of SWG-Based Waveguide Couplers (Experimental Results) silicon segments. It has been recently shown [18] that a jitter as small as 5 nm in the longitudinal position or size of the Si segments of a comparatively wide (multimode) SWG waveguide may cause a significant reduction in the transmittance (∼3 dB loss penalty per 100 µm), degrading the device performance. On the other hand, the effect is practically negligible for narrow (single-mode) SWG waveguides.…”

Section: Proceedings Of the Ieeementioning

confidence: 99%

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

et al. 2018

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Segmenting silicon waveguides at the subwavelength scale produce an equivalent homogenous material. The geometry of the waveguide segments provides precise control over modal confinement, effective index, dispersion and birefringence, thereby opening up new approaches to design devices with unprecedented performance. Indeed, with everimproving lithographic technologies offering sub-100-nm patterning resolution in the silicon photonics platform, many practical devices based on subwavelength structures have been demonstrated in recent years. Subwavelength engineering has thus become an integral design tool in silicon photonics, and both fundamental understanding and novel applications are advancing rapidly. Here, we provide a comprehensive review of the state of the art in this field. We first cover the basics of subwavelength structures, and discuss substrate leakage, fabrication jitter, reduced backscatter, and engineering of material anisotropy. We then review recent applications including broadband waveguide couplers, high-sensitivity evanescent field sensors, low-loss devices for mid-infrared photonics, polarization management structures, spectral filters, and Manuscript

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Section: Proceedings Of the Ieeementioning

confidence: 99%

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

et al. 2018

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“…The tapers between the homogeneous and SWG waveguides in the MZI arms were 30 µm long to avoid transition losses, and the SWG waveguides were 600 µm long to accurately characterize the group index variation; a period of Λ = 0.25 µm was used. To reduce the influence of fabrication jitter, narrow single-mode SWG waveguides are preferred [31], so a width of w c = 1 µm was chosen. Highly-efficient input and output SWG edge couplers [7,14] were used to couple light in and out of the chip with a lensed polarization maintaining fiber (PMF).…”

Section: Resultsmentioning

confidence: 99%

Tilted subwavelength gratings: controlling anisotropy in metamaterial nanophotonic waveguides

et al. 2018

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Subwavelength grating (SWG) structures are an essential tool in silicon photonics, enabling the synthesis of practical metamaterials with controllable refractive index. Here we propose, for the first time, tilting the grating elements to gain control over the anisotropy of the metamaterial. Rigorous FDTD simulations demonstrate that a 45°tilt results in an effective index variation on the fundamental TE mode of 0.23 refractive index units, whereas the change in the TM mode is 20 times smaller. Our simulation predictions are corroborated by experimental results. We furthemore propose an accurate theoretical model for designing tilted SWG structures based on rotated uniaxial crystals, which is functional over a wide wavelength range and for both the fundamental and higher order modes. The proposed structures open up promising venues in polarization management of silicon photonic devices.

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“…For example, fabrication imperfections like slanted or collapsed silicon pillars can lead to reduced transmission, this becomes more probable as the number of periods increases in longer waveguides. Also, disorder effects induced losses arising from variations in period alignment along the waveguides could be more prominent in the wider structures [32].…”

Section: Loss [Db/mm]mentioning

confidence: 99%

Slow Light in Subwavelength Grating Waveguides

Jean

Gervais

LaRochelle

et al. 2020

IEEE J. Select. Topics Quantum Electron.

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Structural slow light is the dispersion engineering process by which the group velocity of light can be drastically reduced in a periodic waveguide structure. Enabling large group delay and enhancing the light-matter interaction on a subwavelength scale, on-chip slow light is of great interest in a vast array of fields such as non-linear optic, sensing, laser physics, telecommunication and computing. In this work, we experimentally demonstrate, for the first time, slow light in subwavelength grating waveguides on the silicon-on-insulator platform. We present a comprehensive numerical study in analytical modelling and 3D FDTD. Multiple waveguides variations were fabricated using an electron-beam lithography process. Figures of merit such as group index, bandwidth and loss-per-delay are examined in both theory and experiment. A maximum measured group index of 47.74 with a loss-per-delay of 103.37 dB/ns has been achieved near the wavelength of 1550 nm. A broad bandwidth of 8.82 nm was measured, in which the group index remains larger than 10. We also show that the region of slow light operation can be shifted over a large wavelength span by controlling a single design parameter.

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Disorder effects in subwavelength grating metamaterial waveguides

Cited by 33 publications

References 27 publications

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

Tilted subwavelength gratings: controlling anisotropy in metamaterial nanophotonic waveguides

Slow Light in Subwavelength Grating Waveguides

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