Query: Silicon photonic devices realized on refractive index engineered subwavelength grating waveguides-a review

Candidate papers:

abstract: Abstract It is a remarkable and straightforward approach to customize the dispersion and nonlinear properties of the photonic devices without varying the composition of the material by employing periodic segmented waveguide structures at the subwavelength level of the operational wavelength. This method addresses the diffraction limit and it is likely to engineer the waveguides as a uniform optical medium with an effective refractive index that relies on the waveguide geometry. In recent years, advances in lithographic technology in the semiconductor on insulator platform providing sub 100 nm patterning resolution have been renowned with many useful devices based on subwavelength structures. At the beginning of the paper, the modal characteristics of the subwavelength grating (SWG) waveguides are presented. And in afterwards, we provide an insight into noteworthy progress in the subwavelength grating (SWG) waveguides based devices for signal processing and sensing applications such as ring resonators for surface and bulk sensing, couplers, suspended membrane waveguides for mid infrared applications, filters, and fiber to chip couplers.
author_names: Nikolay Lvovich Kazanskiy

Muhammad Ali Butt

Svetlana Nikolaevna Khonina
title: Silicon photonic devices realized on refractive index engineered subwavelength grating waveguides A review
year: 2021

abstract: Periodic silicon waveguides with a pitch that is below half the effective wavelength of light support diffraction less Bloch modes. These modes propagate as through a homogeneous, artificial core metamaterial waveguide whose optical characteristics can be engineered by lithographic patterning. Subwavelength gratings (SWGs) provide designers with unique tools to control the refractive index, dispersion and birefringence of the equivalent metamaterial, yielding improved device performance. Based on this approach many high performance optical devices have been designed and experimentally demonstrated in the last years. In this paper we will review the fundamentals of SWG engineering and present some of our latest findings.
author_names: Inigo Molina-Fernandez

Abdelfettah Hadij-ElHouati

Jose Manuel Luque-Gonzalez

Daniel Pereira

Alejandro Sanchez Postigo

Gonzalo Wanguenmert-Perez

Alejandro Ortega-Monux

Robert Halir

Jose de Oliva Rubio

Jens H Schmid

Pavel Cheben

Jiri Ctyroky
title: Subwavelength grating silicon photonic devices
year: 2021

abstract: Surface grating couplers are fundamental components in chip based photonic devices to couple light between photonic integrated circuits and optical fibers. In this work, we report on a grating coupler with sub decibel experimental coupling efficiency using a single etch process in a standard 220 nm silicon on insulator (SOI) platform. We specifically demonstrate a subwavelength metamaterial refractive index engineered nanostructure with backside metal reflector, with the measured peak fiber chip coupling efficiency of 0.69 dB (85.3% and 3 dB bandwidth of 60 nm. This is the highest coupling efficiency hitherto experimentally achieved for a surface grating coupler implemented in 220 nm SOI platform.
author_names: Daniel Benedikovic

Pavel Cheben

Jens H Schmid

Dan-Xia Xu

Boris Lamontagne

Shurui Wang

Jean Lapointe

Robert Halir

Alejandro Ortega-Monux

Siegfried Janz

Milan Dado
title: Subwavelength index engineered surface grating coupler with sub decibel efficiency for 220 nm silicon on insulator waveguides.
venue: Optics express
year: 2015

abstract: Abstract Subwavelength structures such as subwavelength gratings (SWGs) and subwavelength metamaterials are capable of tailoring the optical properties of materials and controlling the flow of light at the nanoscale. The effective indices of the subwavelength structured strip and slab waveguides can be changed in a wide range by choosing an appropriate duty cycle or a filling factor of silicon, which provides an effective method to manipulate the optical field and achieve effective index matching for functional devices. Recent advances in nanofabrication techniques have made it possible to implement subwavelength structures in silicon strip and slab waveguides. Here we review various approaches used to design subwavelength structures and achieve exotic optical responses and discuss how these structures can be used to realize high performance silicon photonic devices. Both one dimensional SWG devices and two dimensional subwavelength metamaterial devices are covered in this review, including subwavelength structure based polarization handling devices, mode manipulation devices, and building blocks for integrated optical interconnects. Perspectives on subwavelength structured silicon photonic devices are also discussed.
author_names: Lu Sun

Yong Zhang

Yu He

Hongwei Wang

Yikai Su
title: Subwavelength structured silicon waveguides and photonic devices
year: 2020

abstract: In the past decade, there has been tremendous progress in using subwavelength scale nanostructures with elaborately designed periodic and disordered photonic materials for applications in integrated photonics. In this paper, we review the advances in subwavelength engineering used in silicon photonic devices, with an emphasis on our own contributions on the use of subwavelength gratings and hyperuniform disordered photonic structures to attain state of the art performances for near and mid infrared applications in fiber chip coupling, slot waveguides for refractive index sensing, mode conversion, wavelength filtering, integrated resonators, and ultracompact high extinction and broadband integrated polarizers.
author_names: Wen Zhou

Zhenzhou Cheng

Xia Chen

Ke Xu

Xiankai Sun

Hon Ki Tsang
title: Subwavelength Engineering in Silicon Photonic Devices
venue: IEEE Journal of Selected Topics in Quantum Electronics
year: 2019

abstract: The subwavelength patterning of planar structures is now widely used in silicon photonics, enabling the synthesis of metamaterials with engineered optical properties, including refractive index, dispersion, and anisotropy. A wide range of integrated devices based on subwavelength grating (SWG) metamaterials have been demonstrated at telecom wavelengths, some with unprecedented performance. The benefits of SWG metamaterials can be leveraged not only in the typical telecom near infrared bands, but also at the longer mid infrared wavelengths. In this invited presentation, we will review our latest developments in SWG based silicon and germanium photonic devices for the near and the midinfrared.
author_names: Alejandro Sanchez-Postigo

J Gonzalo Wanguemert-Perez

Alejandro Ortega-Monux

Robert Halir

Daniel Pereira-Martin

Jose Manuel Luque-Gonzalez

Jens H Schmid

Shurui Wang

Martin Vachon

Dan-Xia Xu

Jordi Soler Penades

Milos S Nedeljkovic

Goran Z Mashanovich

Pavel Cheben

Inigo Molina-Fernandez
title: Subwavelength grating metamaterial integrated devices for the near and mid infrared wavelengths
venue: OPTO
year: 2021

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. (c) 2017 Optical Society of America OCIS codes: (130.0130) Integrated optics; (250.5300) Photonic integrated circuits; (130.3120) Integrated optics devices; (050.6624) Subwavelength structures; (160.3918) Metamaterials. References and links 1. S. M. Rytov, "The electromagnetic properties of finely layered medium," Sov. Phys. JETP 2, 466 475 (1956) 2. M. W. Farn, "Binary gratings with increased efficiency," Appl. Opt. 31(22) 4453 4458 (1992) 3. P. Cheben, D. X. Xu, S. Janz, and A. Densmore, "Subwavelength waveguide grating for mode conversion and light coupling in integrated optics," Opt. Express 14(11) 4695 4702 (2006) 4. P. Cheben, P. J. Bock, J. H. Schmid, J. Lapointe, S. Janz, D. X. Xu, A. Densmore, A. Delage, B. Lamontagne, and T. J. Hall, "Refractive index engineering with subwavelength gratings for efficient microphotonic couplers and planar waveguide multiplexers," Opt. Lett. 35(15) 2526 2528 (2010) 5. P. Cheben, J. H. Schmid, S. Wang, D. X. Xu, M. Vachon, S. Janz, J. Lapointe, Y. Painchaud, and M. J. Picard, "Broadband polarization independent nanophotonic coupler for silicon waveguides with ultra high efficiency," Opt. Express 23(17) 22553 22563 (2015) 6. D. Benedikovic, P. Cheben, J. H. Schmid, D. X. Xu, B. Lamontagne, S. Wang, J. Lapointe, R. Halir, A. OrtegaMonux, S. Janz, and M. Dado, "Subwavelength index engineered surface grating coupler with sub decibel efficiency for 220 nm silicon on insulator waveguides," Opt. Express 23(17) 22628 22635 (2015) 7. D. Benedikovic, C. Alonso Ramos, P. Cheben, J. H. Schmid, S. Wang, R. Halir, A. Ortega Monux, D. X. Xu, L. Vivien, J. Lapointe, S. Janz, and M. Dado, "Single etch subwavelength engineered fiber chip grating couplers for 1.3 mm datacom wavelength band," Opt. Express 24(12) 12893 12904 (2016) 8. X. Xu, H. Subbaraman, J. Covey, D. Kwong, A. Hosseini, and R. T. Chen, "Complementary metal oxide semiconductor compatible high efficiency subwavelength grating couplers for silicon integrated photonics," Appl. Phys. Lett. 101(3) 031109 (2012) 9. A. Sanchez Postigo, J. Gonzalo Wanguemert Perez, J. M. Luque Gonzalez, I. Molina Fernandez, P. Cheben, C. A. Alonso Ramos, R. Halir, J. H. Schmid, and A. Ortega Monux, "Broadband fiber chip zero order surface grating coupler with 0.4 dB efficiency," Opt. Lett. 41(13) 3013 3016 (2016) Vol. 25, No. 11 29 May 2017 OPTICS EXPRESS 12222
author_names: S H

F
title: Disorder effects in subwavelength grating metamaterial waveguides
year: 2019

abstract: In this review, we summarize and discuss our recent studies of subwavelength grating (SWG) structures for engineering the refractive index of silicon microphotonic waveguides. The SWG effect allows control of the effective refractive index of a waveguide core over a range spanning the values of the cladding material and silicon by lithographic patterning. We demonstrate this effect with the example of segmented photonic wire waveguides, which are shown to exhibit low propagation loss, and can be used to make highly efficient waveguide crossings and in plane fiber chip coupling structures. Other applications of SWG structures in silicon photonic waveguide devices include surface grating couplers with enhanced performance and simplified fabrication requirements, as well as a novel curved waveguide sidewall grating micro spectrometer, in which an SWG structure fulfills a dual purpose by acting as an effective slab waveguide for diffracted light and as a lateral cladding for a channel waveguide.
author_names: Jens H Schmid

Pavel Cheben

Przemek J Bock

Robert Halir

Jean Lapointe

Siegfried Janz

Andre Delage

Adam Densmore

Jean-Marc Fedeli

Trevor J Hall

Boris Lamontagne

Rubin Ma

Inigo Molina-Fernandez

D-X Xu
title: Refractive Index Engineering With Subwavelength Gratings in Silicon Microphotonic Waveguides
venue: IEEE Photonics Journal
year: 2011

abstract: Silicon photonics has emerged as an intense field of research due to its unique capabilities to integrate photonics and electronics into the same platform using standard semiconductor fabrication facilities. Subwavelength grating (SWG) structures, i.e. periodic nanostructured waveguides with a pitch below half the wavelength of light, allow the lossless propagation of Bloch Floquet modes which closely resemble propagation through a homogenous waveguide with optical properties (refractive index, dispersion, birefringence) that can be tailored to fulfill specific design goals. SWG engineering is now routinely used for novel and advanced device design. Fiber chip couplers, polarization and mode multiplexers, multimode interference couplers (MMIs) lenses, and bragg filters have been successfully designed in our group based in these concepts. In this invited talk we will review some of our last advances in the field.
author_names: Inigo Molina-Fernandez

J Gonzalo Wanguemert-Perez

Alejandro Ortega-Monux

Robert Halir

Jose de Oliva Rubio

Alejandro Sanchez-Postigo

Jose Manuel Luque-Gonzalez

Abdelfettah Hadij-ElHouati

Daniel Pereira-Martin

David Gonzalez-Andrade

Aitor V Velasco

Alaine Herrero-Bermello

Jens H Schmid

Pavel Cheben

Jiri Ctyroky
title: Silicon subwavelength waveguiding devices
venue: OPTO
year: 2020

abstract: High performance couplers are highly desired in many applications, but the design is limited by nearly unchangeable material refractive index. To tackle this issue, refractive index engineering method is investigated, which can be realized by subwavelength grating. Subwavelength gratings are periodical structures with pitches small enough to locally synthesize the refractive index of photonic waveguides, which allows direct control of optical profile as well as easier fabrication process. This review provides an introduction to the basics of subwavelength structures and pay special attention to the design strategies of some representative examples of subwavelength grating devices, including: edge couplers, fiber chip grating couplers, directional couplers and multimode interference couplers. Benefited from the subwavelength grating which can engineer the refractive index as well as birefringence and dispersion, these devices show better performance when compared to their conventional counterparts.
author_names: Lu Liu

Zhiping James Zhou
title: Refractive index engineering of high performance coupler for compact photonic integrated circuits
year: 2017