Controlling leakage losses in subwavelength grating silicon metamaterial waveguides

Sarmiento-Merenguel, José Darío; Ortega‐Moñux, Alejandro; Fédéli, Jean-Marc; Wangüemert‐Pérez, J. Gonzalo; Alonso-Ramos, C.; Durán-Valdeiglesias, Elena; Cheben, Pavel; Molina-Fernández, Í.; Halir, Robert

doi:10.1364/ol.41.003443

Cited by 62 publications

(24 citation statements)

References 18 publications

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“…For example, in [16] the modes are weakly confined to the point that the Si handle wafer needs to be undercut to prevent leakage. In [17], the authors demonstrated that there is an exponential relation between the Bloch-Floquet mode effective index and leakage losses in SWG waveguides. This relation does not depend of the specific waveguide geometry, but only on the BOX thickness and the mode effective index (the latter determines the modal confinement).…”

Section: Mitigating Substrate Leakage Lossmentioning

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: Mitigating Substrate Leakage Lossmentioning

confidence: 99%

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

et al. 2018

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“…The SWG waveguide comprises N = 200 periods, with the total grating length of L = 200· = 40 µm. The nominal duty cycle was chosen as DC = l Si / = 50%, as it provides sufficient vertical confinement to mitigate power leakage to the silicon substrate [25]. Another important consideration when choosing this initial set of geometrical parameters was our interest in the jitter influence on a realistic structure related to a practical application, namely an ultra-broadband 2 × 2 MMI coupler, which we recently reported using the same technological platform [13].…”

Section: Introductionmentioning

confidence: 99%

Disorder effects in subwavelength grating metamaterial waveguides

et al. 2017

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous. Abstract: Subwavelength grating (SWG) waveguides are integrated photonic structures with a pitch substantially smaller than wavelength for which they are designed, so that diffraction effects are suppressed. SWG operates as an artificial metamaterial with an equivalent refractive index which depends on the geometry of the structure and the polarization of the propagating wave. SWG waveguides have been advantageously used in silicon photonics, resulting in significant performance improvements for many practical devices, including highly efficient fiber-chip couplers, waveguide crossings, broadband multimode interference (MMI) couplers, evanescent field sensors and polarization beam splitters, to name a few. Here we present a theoretical and experimental study of the influence of disorder effects in SWG waveguides. We demonstrate via electromagnetic simulations and experimental measurements that even a comparatively small jitter (~5 nm) in the position and size of the SWG segments may cause a dramatic reduction in the transmittance for wide (multimode) SWG waveguides, while for narrow (single mode) waveguides this effect is negligible. Our study shows that the impact of the jitter on SWG waveguide performance is directly related to the modal confinement.

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“…5(b), inset] was measured by sweeping the wavelength of a tunable laser while measuring output power with a power meter. From the measured transmittance function the group index difference (∆n g ) is calculated using the procedure described in [32]. A comparison with the FDTD simulation results [ Fig.…”

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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Controlling leakage losses in subwavelength grating silicon metamaterial waveguides

Cited by 62 publications

References 18 publications

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

Subwavelength-Grating Metamaterial Structures for Silicon Photonic Devices

Disorder effects in subwavelength grating metamaterial waveguides

Tilted subwavelength gratings: controlling anisotropy in metamaterial nanophotonic waveguides

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