1
|
Abstract
With the increasing demand for capacity in communications networks, the use of integrated photonics to transmit, process and manipulate digital and analog signals has been extensively explored. Silicon photonics, exploiting the complementary-metal-oxide-semiconductor (CMOS)-compatible fabrication technology to realize low-cost, robust, compact, and power-efficient integrated photonic circuits, is regarded as one of the most promising candidates for next-generation chip-scale information and communication technology (ICT). However, the electro-optic modulators, a key component of Silicon photonics, face challenges in addressing the complex requirements and limitations of various applications under state-of-the-art technologies. In recent years, the graphene EO modulators, promising small footprints, high temperature stability, cost-effective, scalable integration and a high speed, have attracted enormous interest regarding their hybrid integration with SiPh on silicon-on-insulator (SOI) chips. In this paper, we summarize the developments in the study of silicon-based graphene EO modulators, which covers the basic principle of a graphene EO modulator, the performance of graphene electro-absorption (EA) and electro-refractive (ER) modulators, as well as the recent advances in optical communications and microwave photonics (MWP). Finally, we discuss the emerging challenges and potential applications for the future practical use of silicon-based graphene EO modulators.
Collapse
|
2
|
Wen H, Ren L, Shi L, Zhang X. Parity-time symmetry in monolithically integrated graphene-assisted microresonators. OPTICS EXPRESS 2022; 30:2112-2121. [PMID: 35209358 DOI: 10.1364/oe.448371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
Recently, optical systems with parity-time (PT) symmetry have attracted considerable attention due to its remarkable properties and promising applications. However, these systems usually require separate photonic devices or active semiconductor materials. Here, we investigate PT symmetry and exceptional points (EPs) in monolithically integrated graphene-assisted coupled microresonators. Raman effect and graphene cladding are utilized to introduce the balanced gain and loss. We show that PT-symmetry breaking and EPs can be achieved by changing the pump power and the chemical potential. In addition, the intracavity field intensities experience suppression and revival as the graphene-induced loss increases. Due to the unique distribution of optical field, tunable nonreciprocal light transmission is theoretically demonstrated when introducing the gain saturation nonlinearity. The maximum isolation ratio can reach 26 dB through optimizing the relevant parameters. Our proposed scheme is monolithically integrated, CMOS compatible, and exhibits remarkable properties for microscale light field manipulation. These superior features make our scheme has promising applications in optical communication, computing and sensing.
Collapse
|
3
|
All-Optical Modulation Technology Based on 2D Layered Materials. MICROMACHINES 2022; 13:mi13010092. [PMID: 35056256 PMCID: PMC8780208 DOI: 10.3390/mi13010092] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 12/07/2021] [Accepted: 12/16/2021] [Indexed: 02/01/2023]
Abstract
In the advancement of photonics technologies, all-optical systems are highly demanded in ultrafast photonics, signal processing, optical sensing and optical communication systems. All-optical devices are the core elements to realize the next generation of photonics integration system and optical interconnection. Thus, the exploration of new optoelectronics materials that exhibit different optical properties is a highlighted research direction. The emerging two-dimensional (2D) materials such as graphene, black phosphorus (BP), transition metal dichalcogenides (TMDs) and MXene have proved great potential in the evolution of photonics technologies. The optical properties of 2D materials comprising the energy bandgap, third-order nonlinearity, nonlinear absorption and thermo-optics coefficient can be tailored for different optical applications. Over the past decade, the explorations of 2D materials in photonics applications have extended to all-optical modulators, all-optical switches, an all-optical wavelength converter, covering the visible, near-infrared and Terahertz wavelength range. Herein, we review different types of 2D materials, their fabrication processes and optical properties. In addition, we also summarize the recent advances of all-optical modulation based on 2D materials. Finally, we conclude on the perspectives on and challenges of the future development of the 2D material-based all-optical devices.
Collapse
|
4
|
Ojaghi S, Golmohammadi S, Soofi H. All-optical graphene-on-silicon slot waveguide modulator based on graphene's Kerr effect. APPLIED OPTICS 2021; 60:7945-7954. [PMID: 34613054 DOI: 10.1364/ao.427755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/08/2021] [Indexed: 06/13/2023]
Abstract
All-optical graphene-based optical modulators have recently attracted much attention because of their ultrafast and broadband response characteristics (bandwidth larger than 100 GHz) in comparison with the previous graphene-based optical modulators, which are electrically tuned via the graphene Fermi level. Silicon photonics has some benefits such as low cost and high compatibility with CMOS design and manufacturing technology. On the other hand, graphene has a unique large nonlinear Kerr coefficient, which we calculate using graphene's tight-binding model based on the semiconductor Bloch equations. Its real and imaginary parts are negative at the wavelength of 1.55 µm and EF=0.1eV. To simultaneously use the benefits mentioned above, we present an all-optical, CMOS-compatible, and graphene-on-silicon slot (GOSS) waveguide extinction and phase modulator that consists of two different geometries. The first one consists of a one-stage GOSS waveguide with a single layer of graphene. To increase the light-graphene interaction and consequently enhance the modulation efficiency (ME), another stage of the GOSS waveguide is placed over the first one. This two-stage configuration is called a graphene-on-silicon double-slot (GOSDS) waveguide. The ME, insertion loss (IL), and modulation depth (MD) for a 12.5 µm GOSDS waveguide modulator with a double layer of graphene can reach 0.241 dB/µm, 1.31 dB, and 77%, respectively, at optical pump intensities about 9MWcm-2. Our design has a smaller waveguide length (17.6 times) than the previous all-optical graphene-on-silicon ribbon waveguide extinction modulator and high MD (about 2 times) in comparison with a graphene-clad microfiber all-optical extinction modulator. Compared with an all-optical Mach-Zehnder interferometer phase modulator, our design has short graphene coated waveguide length (≈0.1 times) and low local optical intensities (≈0.043 times) needed for π phase shift. This study may promote the design and realization of high-performance, wideband, compact, and all-optical control on a single chip with a reasonable contrast level.
Collapse
|
5
|
Wang B, Kim S, Zhai T, Seok J, Yang H, Salas-Montiel R. Near-field probing of dielectric screening by hexagonal boron nitride in graphene integrated on silicon photonics. NANOTECHNOLOGY 2021; 32:315207. [PMID: 33892483 DOI: 10.1088/1361-6528/abfb31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Hexagonal boron nitride (hBN) is one of the most suitable 2D materials for supporting graphene in electronic devices, and it plays a fundamental role in screening out the effect of charge impurities in graphene in contrast to inhomogeneous supports such as silicon dioxide (SiO2). Although many interesting surface science techniques such as scanning tunneling microscopy (STM) revealed dielectric screening by hBN and emergent physical phenomena were observed, STM is only appropriate for graphene electronics. In this paper, we demonstrate the dielectric screening by hBN in graphene integrated on a silicon photonic waveguide from the perspective of a near-field scanning optical microscopy (NSOM) and Raman spectroscopy. We found shifts in the Raman spectra and about three times lower slope decrease in the measured electric near-field amplitude for graphene on hBN relative to that for graphene on SiO2. Based on finite-difference time-domain simulations, we confirm lower electric field slope and scattering rate in graphene on hBN, which implies dielectric screening, in agreement with the NSOM signal. Graphene on hBN integrated on silicon photonics can pave the way for high-performance hybrid graphene photonics.
Collapse
Affiliation(s)
- Binbin Wang
- Light, Nanomaterials, Nanotechnologies (L2n) Laboratory, CNRS ERL 7004, University of Technology of Troyes,10004 Troyes, France
- Key Laboratory of Light-Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China
| | - Sera Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Tingting Zhai
- Light, Nanomaterials, Nanotechnologies (L2n) Laboratory, CNRS ERL 7004, University of Technology of Troyes,10004 Troyes, France
| | - Jinbong Seok
- Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Heejun Yang
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Rafael Salas-Montiel
- Light, Nanomaterials, Nanotechnologies (L2n) Laboratory, CNRS ERL 7004, University of Technology of Troyes,10004 Troyes, France
| |
Collapse
|
6
|
Giambra M, Mišeikis V, Pezzini S, Marconi S, Montanaro A, Fabbri F, Sorianello V, Ferrari AC, Coletti C, Romagnoli M. Wafer-Scale Integration of Graphene-Based Photonic Devices. ACS NANO 2021; 15:3171-3187. [PMID: 33522789 PMCID: PMC7905876 DOI: 10.1021/acsnano.0c09758] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/21/2021] [Indexed: 05/13/2023]
Abstract
Graphene and related materials can lead to disruptive advances in next-generation photonics and optoelectronics. The challenge is to devise growth, transfer and fabrication protocols providing high (≥5000 cm2 V-1 s-1) mobility devices with reliable performance at the wafer scale. Here, we present a flow for the integration of graphene in photonics circuits. This relies on chemical vapor deposition (CVD) of single layer graphene (SLG) matrices comprising up to ∼12000 individual single crystals, grown to match the geometrical configuration of the devices in the photonic circuit. This is followed by a transfer approach which guarantees coverage over ∼80% of the device area, and integrity for up to 150 mm wafers, with room temperature mobility ∼5000 cm2 V-1 s-1. We use this process flow to demonstrate double SLG electro-absorption modulators with modulation efficiency ∼0.25, 0.45, 0.75, 1 dB V-1 for device lengths ∼30, 60, 90, 120 μm. The data rate is up to 20 Gbps. Encapsulation with single-layer hexagonal boron nitride (hBN) is used to protect SLG during plasma-enhanced CVD of Si3N4, ensuring reproducible device performance. The processes are compatible with full automation. This paves the way for large scale production of graphene-based photonic devices.
Collapse
Affiliation(s)
- Marco
A. Giambra
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
- INPHOTEC, Via G. Moruzzi 1, 56124 Pisa, Italy
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Vaidotas Mišeikis
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Sergio Pezzini
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- NEST,
Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Simone Marconi
- Photonic
Networks and Technologies Lab, Tecip Institute, Scuola Superiore Sant’Anna, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Alberto Montanaro
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Filippo Fabbri
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- NEST,
Scuola Normale Superiore and Istituto Nanoscienze-CNR, Piazza San Silvestro 12, I-56127 Pisa, Italy
| | - Vito Sorianello
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Andrea C. Ferrari
- Cambridge
Graphene Centre, Cambridge University, 9 J.J. Thompson, Cambridge, U.K.
| | - Camilla Coletti
- Center
for Nanotechnology Innovation @NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, I-56127 Pisa, Italy
- Graphene
Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Marco Romagnoli
- Photonic
Networks and Technologies Lab, CNIT, Via G. Moruzzi 1, 56124 Pisa, Italy
- INPHOTEC, Via G. Moruzzi 1, 56124 Pisa, Italy
- CamGraPhiC, Via Moruzzi 1, 56124 Pisa, Italy
| |
Collapse
|
7
|
A Broadband Polarization-Insensitive Graphene Modulator Based on Dual Built-in Orthogonal Slots Plasmonic Waveguide. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11041897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A broadband polarization-insensitive graphene modulator has been proposed. The dual built-in orthogonal slots waveguide allows polarization independence for the transverse electric (TE) mode and the transverse magnetic (TM) mode. Due to the introduction of metal slots in both the vertical and horizontal directions, the optical field as well as the electro-absorption of graphene are enhanced by the plasmonic effect. The proposed electro-optic modulator shows a modulation depth of 0.474 and 0.462 dB/μm for two supported modes, respectively. An ultra-low effective index difference of 0.001 can be achieved within the wavelength range from 1100 to 1900 nm. The 3 dB-bandwidth is estimated to be 101 GHz. The power consumption is 271 fJ/bit at a modulation length of 20 μm. The proposed modulator provides high speed broadband solutions in microwave photonic systems.
Collapse
|
8
|
Wu J, Ma H, Yin P, Ge Y, Zhang Y, Li L, Zhang H, Lin H. Two‐Dimensional Materials for Integrated Photonics: Recent Advances and Future Challenges. SMALL SCIENCE 2021. [DOI: 10.1002/smsc.202000053] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Jianghong Wu
- Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang College of Information Science & Electronic Engineering Zhejiang University Hangzhou 310027 China
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of Engineering Westlake University Hangzhou 310024 China
- Institute of Advanced Technology Westlake Institute for Advanced Study 18 Shilongshan Road Hangzhou 310024 China
| | - Hui Ma
- Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang College of Information Science & Electronic Engineering Zhejiang University Hangzhou 310027 China
| | - Peng Yin
- Institute of Microscale Optoelectronics Collaborative Innovation Centre for Optoelectronic Science & Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology Guangdong Laboratory of Artificial
| | - Yanqi Ge
- Institute of Microscale Optoelectronics Collaborative Innovation Centre for Optoelectronic Science & Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology Guangdong Laboratory of Artificial
| | - Yupeng Zhang
- Institute of Microscale Optoelectronics Collaborative Innovation Centre for Optoelectronic Science & Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology Guangdong Laboratory of Artificial
| | - Lan Li
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of Engineering Westlake University Hangzhou 310024 China
- Institute of Advanced Technology Westlake Institute for Advanced Study 18 Shilongshan Road Hangzhou 310024 China
| | - Han Zhang
- Institute of Microscale Optoelectronics Collaborative Innovation Centre for Optoelectronic Science & Technology International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen Key Laboratory of Micro-Nano Photonic Information Technology Guangdong Laboratory of Artificial
| | - Hongtao Lin
- Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang College of Information Science & Electronic Engineering Zhejiang University Hangzhou 310027 China
| |
Collapse
|
9
|
Agarwal H, Terrés B, Orsini L, Montanaro A, Sorianello V, Pantouvaki M, Watanabe K, Taniguchi T, Thourhout DV, Romagnoli M, Koppens FHL. 2D-3D integration of hexagonal boron nitride and a high-κ dielectric for ultrafast graphene-based electro-absorption modulators. Nat Commun 2021; 12:1070. [PMID: 33594048 PMCID: PMC7887197 DOI: 10.1038/s41467-021-20926-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/18/2020] [Indexed: 11/18/2022] Open
Abstract
Electro-absorption (EA) waveguide-coupled modulators are essential building blocks for on-chip optical communications. Compared to state-of-the-art silicon (Si) devices, graphene-based EA modulators promise smaller footprints, larger temperature stability, cost-effective integration and high speeds. However, combining high speed and large modulation efficiencies in a single graphene-based device has remained elusive so far. In this work, we overcome this fundamental trade-off by demonstrating the 2D-3D dielectric integration in a high-quality encapsulated graphene device. We integrated hafnium oxide (HfO2) and two-dimensional hexagonal boron nitride (hBN) within the insulating section of a double-layer (DL) graphene EA modulator. This combination of materials allows for a high-quality modulator device with high performances: a ~39 GHz bandwidth (BW) with a three-fold increase in modulation efficiency compared to previously reported high-speed modulators. This 2D-3D dielectric integration paves the way to a plethora of electronic and opto-electronic devices with enhanced performance and stability, while expanding the freedom for new device designs. Here, three-dimensional hafnium oxide and two-dimensional hexagonal boron nitride are integrated in the insulating section of double-layer graphene optical modulators, leading to a maximum bandwidth of 39 GHz and enhanced modulation efficiency.
Collapse
Affiliation(s)
- Hitesh Agarwal
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain
| | - Bernat Terrés
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain.
| | - Lorenzo Orsini
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain.,Dipartimento di Fisica "E. Fermi", Università di Pisa, Pisa, 56127, Italy
| | - Alberto Montanaro
- Consorzio Nazionale per le Telecomunicazioni (CNIT), Photonic Networks and Technologies National Laboratory, Pisa, 56124, Italy
| | - Vito Sorianello
- Consorzio Nazionale per le Telecomunicazioni (CNIT), Photonic Networks and Technologies National Laboratory, Pisa, 56124, Italy
| | | | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tuskuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, 305-0044, Japan
| | - Dries Van Thourhout
- Photonics Research Group, Department of Information Technology, Ghent University-IMEC, Gent, 9000, Belgium
| | - Marco Romagnoli
- Consorzio Nazionale per le Telecomunicazioni (CNIT), Photonic Networks and Technologies National Laboratory, Pisa, 56124, Italy
| | - Frank H L Koppens
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), 08860, Spain. .,ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, 08010, Spain.
| |
Collapse
|
10
|
Xu Z, Yang S, Wang J. Nanoscale phase modulator and optical switch based on graphene-coated fiber. APPLIED OPTICS 2020; 59:6218-6223. [PMID: 32672770 DOI: 10.1364/ao.389532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
The new, to the best of our knowledge, phase modulator and optical switch based on graphene-coated fiber are proposed and studied. The fields of surface plasmon polaritons (SPP) modes are highly concentrated on the graphene so that very high effective indices (>400) can be achieved. By virtue of this feature, the dimensions of these devices can be as small as several nanometers in length. The minimum transmission losses for the phase modulator and optical switch are 0.54 dB and 0.18 dB, respectively. The maximum voltage adjustment range needed is only 0.3 V. The optical switch possesses a complete switch-off state and is adaptable to variation in phase difference and light intensity. The performance of these devices can be effectively tuned by the parameters, such as the graphene-coated lengths and the applied voltages. These devices may have important applications in fiber-based systems and other nanoscale optic and optoelectronic systems.
Collapse
|
11
|
Illarionov YY, Knobloch T, Jech M, Lanza M, Akinwande D, Vexler MI, Mueller T, Lemme MC, Fiori G, Schwierz F, Grasser T. Insulators for 2D nanoelectronics: the gap to bridge. Nat Commun 2020; 11:3385. [PMID: 32636377 PMCID: PMC7341854 DOI: 10.1038/s41467-020-16640-8] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 05/15/2020] [Indexed: 12/02/2022] Open
Abstract
Nanoelectronic devices based on 2D materials are far from delivering their full theoretical performance potential due to the lack of scalable insulators. Amorphous oxides that work well in silicon technology have ill-defined interfaces with 2D materials and numerous defects, while 2D hexagonal boron nitride does not meet required dielectric specifications. The list of suitable alternative insulators is currently very limited. Thus, a radically different mindset with respect to suitable insulators for 2D technologies may be required. We review possible solution scenarios like the creation of clean interfaces, production of native oxides from 2D semiconductors and more intensive studies on crystalline insulators.
Collapse
Affiliation(s)
- Yury Yu Illarionov
- Institute for Microelectronics (TU Wien), Gusshausstrasse 27-29, 1040, Vienna, Austria.
- Ioffe Physical-Technical Institute, Polytechnicheskaya 26, St-Petersburg, Russia, 194021.
| | - Theresia Knobloch
- Institute for Microelectronics (TU Wien), Gusshausstrasse 27-29, 1040, Vienna, Austria
| | - Markus Jech
- Institute for Microelectronics (TU Wien), Gusshausstrasse 27-29, 1040, Vienna, Austria
| | - Mario Lanza
- Institute of Functional Nano & Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Building 910, 215123, Suzhou, China
| | - Deji Akinwande
- The University of Texas at Austin, 10100 Burnet Rd. 160, Austin, TX, 78758, USA
| | - Mikhail I Vexler
- Ioffe Physical-Technical Institute, Polytechnicheskaya 26, St-Petersburg, Russia, 194021
| | - Thomas Mueller
- Institute for Photonics (TU Wien), Gusshausstrasse 27-29, 1040, Vienna, Austria
| | - Max C Lemme
- AMO GmbH, Advanced Microelectronic Center Aachen (AMICA), Otto-Blumenthal-Str. 25, 52074, Aachen, Germany
- Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal-Str. 2, 52074, Aachen, Germany
| | - Gianluca Fiori
- Dipartimento di Ingegneria dell'Informazione, Università di Pisa, 56122, Pisa, Italy
| | - Frank Schwierz
- Institute for Micro- and Nanoelectronics, Technical University Ilmenau, PF 100565, 98684, Ilmenau, Germany
| | - Tibor Grasser
- Institute for Microelectronics (TU Wien), Gusshausstrasse 27-29, 1040, Vienna, Austria.
| |
Collapse
|
12
|
Alessandri C, Asselberghs I, Brems S, Huyghebaert C, Van Campenhout J, Van Thourhout D, Pantouvaki M. 5 × 25 Gbit/s WDM transmitters based on passivated graphene-silicon electro-absorption modulators. APPLIED OPTICS 2020; 59:1156-1162. [PMID: 32225255 DOI: 10.1364/ao.383462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Today, one of the key challenges of graphene devices is establishing fabrication processes that can ensure performance stability and repeatability and that can eventually enable production in high volumes. In this paper, we use up-scalable fabrication processes to demonstrate three five-channel wavelength-division multiplexing (WDM) transmitters, each based on five graphene-silicon electro-absorption modulators. A passivation-first approach is used to encapsulate graphene, which results in hysteresis-free and uniform performance across the five channels of each WDM transmitter, for a total of 15 modulators. Open-eye diagrams are obtained at 25 Gb/s using $ 2.5\;{{\rm V}_{{\rm pp}}} $2.5Vpp, thus demonstrating potential for multi-channel data transmission at ${5}\times {25}\;{\rm Gb/s}$5×25Gb/s on each of the three WDM transmitters.
Collapse
|
13
|
Hao R, Jiao J, Peng X, Zhen Z, Dagarbek R, Zou Y, Li E. Experimental demonstration of a graphene-based hybrid plasmonic modulator. OPTICS LETTERS 2019; 44:2586-2589. [PMID: 31090738 DOI: 10.1364/ol.44.002586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 04/19/2019] [Indexed: 06/09/2023]
Abstract
In this Letter, we report a graphene-based hybrid plasmonic modulator (GHPM) realized by employing the electro-absorption effect of graphene. The simulation results show that the modulation efficiency of GHPM, i.e., extinction ratio per length, can be as large as 0.417 dB/μm, which is more than twice as much as that of recently presented graphene-on-silicon modulator. It was found that the improvement in modulation efficiency is mainly due to the enhancement of the overlap between graphene and the mode field in GHPM. A prototype of GHPM was fabricated. The measurement results showed that the GHPM can work in a broadband from 1530 to 1570 nm and an improved modulation efficiency of 1.08 dB (at 30 μm). Finally, we have discussed the factors that influence the modulation efficiency. Our proof-of-concept design may promote the development of on-chip graphene-based plasmonic devices.
Collapse
|
14
|
Liu J, Khan ZU, Sarjoghian S. Suspended graphene double-layer modulator with an ultrahigh figure of merit and a subwavelength-thickness modulator with leaky mode. APPLIED OPTICS 2019; 58:3729-3734. [PMID: 31158187 DOI: 10.1364/ao.58.003729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
A comparison between a graphene suspended double-layer modulator and a subwavelength-thickness modulator is presented. The physics of both are analyzed in detail and show a confined mode in the suspended modulator but a leaky mode in the subwavelength modulator. The leaky mode shows zero light-matter interaction and zero modulation depth, which should be avoided in designing a modulator. The suspended modulator can achieve much lower insertion loss and an extraordinarily higher figure of merit (∼2480) than the subwavelength modulator. Both operate with high modulation efficiency and comparable modulation speeds. We believe these designs will pave the way to realizing high-efficiency, near-fundamental-limit graphene modulators.
Collapse
|
15
|
Implementation of Atomically Thick Graphene and Its Derivatives in Electromagnetic Absorbers. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To reduce the radar cross section at microwave frequencies, it is necessary to implement electromagnetic (EM) absorbing devices/materials to decrease the strength of reflected waves. In addition, EM absorbers also find their applications at higher spectrum such as THz and optical frequencies. As an atomic-thick two-dimensional (2D) material, graphene has been widely used in the development of EM devices. The conductivity of graphene can be electrostatically or chemically tuned from microwave to optical light frequencies, enabling the design of reconfigurable graphene EM absorbers. Meanwhile, the derivatives of graphene such as reduced graphene oxide (rGO) also demonstrate excellent wave absorbing properties when mixed with other materials. In this article, the research progress of graphene and its derivatives based EM absorbers are introduced and the future development of graphene EM absorbing devices are also discussed.
Collapse
|
16
|
Gao L, Ran H, Cao Y, Li Y, Huang W, Huang L, Feng D, Tang X, Zhu T. Coherent optical modulation of graphene based on coherent population oscillation. OPTICS LETTERS 2019; 44:223-226. [PMID: 30644866 DOI: 10.1364/ol.44.000223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
The optical modulation of graphene circumvents the "electrical bottleneck" in electrical field tuning of the Fermi level and motivates diverse graphene-based controllable photonic devices with extraordinary performances. Unfortunately, pervious optical modulation schemes are incoherent, and the Fermi-Dirac distribution formed from a strong pump laser prevents the absorption of a weak probe laser due to the Pauli blocking, making the modulation inconvenient and low in efficiency. Here we demonstrate the coherent optical modulation of graphene based on coherent population oscillation, where ground state population oscillates with a beat frequency equal to the pump and probe frequency difference. To distinguish it from the coexisting incoherent modulation in graphene, a phase-sensitive pump-probe system is constructed with a fiber-based Mach-Zehnder interferometer. Clear resonance within the burning hole of a pump laser is observed in the interference spectrum of a coherent probe laser. The discovery of highly coherent ground state population oscillation in graphene offers new possibilities for manipulating and controlling the phase response of graphene-based photonics with high efficiency.
Collapse
|
17
|
Shu H, Su Z, Huang L, Wu Z, Wang X, Zhang Z, Zhou Z. Significantly High Modulation Efficiency of Compact Graphene Modulator Based on Silicon Waveguide. Sci Rep 2018; 8:991. [PMID: 29343755 PMCID: PMC5772525 DOI: 10.1038/s41598-018-19171-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 12/21/2017] [Indexed: 11/25/2022] Open
Abstract
We theoretically and experimentally demonstrate a significantly large modulation efficiency of a compact graphene modulator based on a silicon waveguide using the electro refractive effect of graphene. The modulation modes of electro-absorption and electro-refractive can be switched with different applied voltages. A high extinction ratio of 25 dB is achieved in the electro-absorption modulation mode with a driving voltage range of 0 V to 1 V. For electro-refractive modulation, the driving voltage ranges from 1 V to 3 V with a 185-pm spectrum shift. The modulation efficiency of 1.29 V · mm with a 40-μm interaction length is two orders of magnitude higher than that of the first reported graphene phase modulator. The realisation of phase and intensity modulation with graphene based on a silicon waveguide heralds its potential application in optical communication and optical interconnection systems.
Collapse
Affiliation(s)
- Haowen Shu
- State Key Laboratory of Advanced Optical Communications System and Networks, Peking University, Beijing, 100871, China
| | - Zhaotang Su
- State Key Laboratory of Advanced Optical Communications System and Networks, Peking University, Beijing, 100871, China
| | - Le Huang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Peking University, Beijing, 100871, China
| | - Zhennan Wu
- State Key Laboratory of Advanced Optical Communications System and Networks, Peking University, Beijing, 100871, China
| | - Xingjun Wang
- State Key Laboratory of Advanced Optical Communications System and Networks, Peking University, Beijing, 100871, China.
| | - Zhiyong Zhang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Peking University, Beijing, 100871, China.
| | - Zhiping Zhou
- State Key Laboratory of Advanced Optical Communications System and Networks, Peking University, Beijing, 100871, China
| |
Collapse
|
18
|
Mohsin M, Schall D, Otto M, Chmielak B, Porschatis C, Bolten J, Neumaier D. Graphene based on-chip variable optical attenuator operating at 855 nm wavelength. OPTICS EXPRESS 2017; 25:31660-31669. [PMID: 29245837 DOI: 10.1364/oe.25.031660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/12/2017] [Indexed: 06/07/2023]
Abstract
This work reports on the fabrication and characterization of a graphene based variable optical attenuator integrated on a photonic Si3N4 waveguide and operating at 855 nm wavelength. The variable optical attenuator utilizes the gate voltage dependent optical absorption of a graphene layer, located in the evanescent field of the waveguide. A maximum attenuation of 17 dB is obtained at -3 V gate voltages for a device length of 700 µm. The measured voltage dependent absorption was found to be in good agreement with theoretical simulations, taking into account inter- and intra-band optical conductivity of graphene. An outlook is given on possible margins for increasing the operation speed and reducing the insertion loss of the device, using an optimized layout and improved fabrication processes.
Collapse
|
19
|
Ding Y, Guan X, Zhu X, Hu H, Bozhevolnyi SI, Oxenløwe LK, Jin KJ, Mortensen NA, Xiao S. Efficient electro-optic modulation in low-loss graphene-plasmonic slot waveguides. NANOSCALE 2017; 9:15576-15581. [PMID: 28984878 DOI: 10.1039/c7nr05994a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Surface plasmon polaritons enable light concentration within subwavelength regions, opening thereby new avenues for miniaturizing the device and strengthening light-matter interactions. Here we realize efficient electro-optic modulation in low-loss plasmonic waveguides with the aid of graphene, and the devices are fully integrated in the silicon-on-insulator platform. By advantageously exploiting low-loss plasmonic slot-waveguide modes, which weakly leak into a substrate while featuring strong fields within the two-layer-graphene covered slots in metals, we successfully achieve a tunability of 0.13 dB μm-1 for our fabricated graphene-plasmonic waveguide devices with extremely low insertion loss, which outperforms previously reported graphene-plasmonic devices. Our results highlight the potential of graphene plasmonic leaky-mode hybrid waveguides to realize active ultra-compact devices for optoelectronic applications.
Collapse
Affiliation(s)
- Y Ding
- Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Fan M, Yang H, Zheng P, Hu G, Yun B, Cui Y. Multilayer graphene electro-absorption optical modulator based on double-stripe silicon nitride waveguide. OPTICS EXPRESS 2017; 25:21619-21629. [PMID: 29041458 DOI: 10.1364/oe.25.021619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/02/2017] [Indexed: 06/07/2023]
Abstract
A graphene electro-absorption optical modulator based on double-stripe silicon nitride waveguide is proposed and analyzed. By embedding four graphene layers in the double-stripe silicon nitride waveguide and the graphene layers co-electrode design, the total metal-graphene contact resistance can be reduced 50% and as high as 30.6GHz modulation bandwidth can be achieved theoretically. The calculated extinction ratio and figure of merit are 0.1658dB/um and 9.7, respectively. And the required switching voltage from its minimum to maximum absorption state is 3.8180V and 780.50fJ/bit power consuming can be achieved. The proposed modulator can remedy the lack of high speed modulator on the passive silicon nitride waveguide.
Collapse
|
21
|
Rodriguez FJ, Aznakayeva DE, Marshall OP, Kravets VG, Grigorenko AN. Solid-State Electrolyte-Gated Graphene in Optical Modulators. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1606372. [PMID: 28295647 DOI: 10.1002/adma.201606372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/13/2017] [Indexed: 06/06/2023]
Abstract
The gate-tunable wide-band absorption of graphene makes it suitable for light modulation from terahertz to visible light. The realization of graphene-based modulators, however, faces challenges connected with graphene's low absorption and the high electric fields necessary to change graphene's optical conductivity. Here, a solid-state supercapacitor effect with the high-k dielectric hafnium oxide is demonstrated that allows modulation from the near-infrared to shorter wavelengths close to the visible spectrum with remarkably low voltages (≈3 V). The electroabsorption modulators are based on a Fabry-Perot-resonator geometry that allows modulation depths over 30% for free-space beams.
Collapse
Affiliation(s)
- Francisco J Rodriguez
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Diana E Aznakayeva
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Owen P Marshall
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Vasyl G Kravets
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | | |
Collapse
|
22
|
Yu S, Wu X, Wang Y, Guo X, Tong L. 2D Materials for Optical Modulation: Challenges and Opportunities. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28220971 DOI: 10.1002/adma.201606128] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 01/16/2017] [Indexed: 05/09/2023]
Abstract
Owing to their atomic layer thickness, strong light-material interaction, high nonlinearity, broadband optical response, fast relaxation, controllable optoelectronic properties, and high compatibility with other photonic structures, 2D materials, including graphene, transition metal dichalcogenides and black phosphorus, have been attracting increasing attention for photonic applications. By tuning the carrier density via electrical or optical means that modifies their physical properties (e.g., Fermi level or nonlinear absorption), optical response of the 2D materials can be instantly changed, making them versatile nanostructures for optical modulation. Here, up-to-date 2D material-based optical modulation in three categories is reviewed: free-space, fiber-based, and on-chip configurations. By analysing cons and pros of different modulation approaches from material and mechanism aspects, the challenges faced by using these materials for device applications are presented. In addition, thermal effects (e.g., laser induced damage) in 2D materials, which are critical to practical applications, are also discussed. Finally, the outlook for future opportunities of these 2D materials for optical modulation is given.
Collapse
Affiliation(s)
- Shaoliang Yu
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaoqin Wu
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Yipei Wang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xin Guo
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Limin Tong
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
| |
Collapse
|
23
|
|
24
|
Slow-light-enhanced energy efficiency for graphene microheaters on silicon photonic crystal waveguides. Nat Commun 2017; 8:14411. [PMID: 28181531 PMCID: PMC5309776 DOI: 10.1038/ncomms14411] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/24/2016] [Indexed: 12/22/2022] Open
Abstract
Slow light has been widely utilized to obtain enhanced nonlinearities, enhanced spontaneous emissions and increased phase shifts owing to its ability to promote light–matter interactions. By incorporating a graphene on a slow-light silicon photonic crystal waveguide, here we experimentally demonstrate an energy-efficient graphene microheater with a tuning efficiency of 1.07 nmmW−1 and power consumption per free spectral range of 3.99 mW. The rise and decay times (10–90%) are only 750 and 525 ns, which, to the best of our knowledge, are the fastest reported response times for microheaters in silicon photonics. The corresponding figure of merit of the device is 2.543 nW s, one order of magnitude better than results reported in previous studies. The influence of the length and shape of the graphene heater to the tuning efficiency is further investigated, providing valuable guidelines for enhancing the tuning efficiency of the graphene microheater. Slow light can be used to sustain strong light–matter interaction in silicon photonics. Here, the authors combine graphene with a silicon slow-light photonic crystal waveguide, demonstrating a fast and energy-efficient graphene microheater.
Collapse
|
25
|
Schuler S, Schall D, Neumaier D, Dobusch L, Bethge O, Schwarz B, Krall M, Mueller T. Controlled Generation of a p-n Junction in a Waveguide Integrated Graphene Photodetector. NANO LETTERS 2016; 16:7107-7112. [PMID: 27715060 DOI: 10.1021/acs.nanolett.6b03374] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
With its electrically tunable light absorption and ultrafast photoresponse, graphene is a promising candidate for high-speed chip-integrated photonics. The generation mechanisms of photosignals in graphene photodetectors have been studied extensively in the past years. However, the knowledge about efficient light conversion at graphene p-n junctions has not yet been translated into high-performance devices. Here, we present a graphene photodetector integrated on a silicon slot-waveguide, acting as a dual gate to create a p-n junction in the optical absorption region of the device. While at zero bias the photothermoelectric effect is the dominant conversion process, an additional photoconductive contribution is identified in a biased configuration. Extrinsic responsivities of 35 mA/W, or 3.5 V/W, at zero bias and 76 mA/W at 300 mV bias voltage are achieved. The device exhibits a 3 dB bandwidth of 65 GHz, which is the highest value reported for a graphene-based photodetector.
Collapse
Affiliation(s)
- Simone Schuler
- Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria
| | - Daniel Schall
- AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany
| | | | - Lukas Dobusch
- Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria
| | - Ole Bethge
- Institute of Solid State Electronics, Vienna University of Technology , Floragasse 7, 1040 Vienna, Austria
| | - Benedikt Schwarz
- Institute of Solid State Electronics, Vienna University of Technology , Floragasse 7, 1040 Vienna, Austria
| | - Michael Krall
- Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria
| | - Thomas Mueller
- Institute of Photonics, Vienna University of Technology , Gußhausstraße 27-29, 1040 Vienna, Austria
| |
Collapse
|
26
|
Cai H, Cheng Y, Zhang H, Huang Q, Xia J, Barille R, Wang Y. Enhanced linear absorption coefficient of in-plane monolayer graphene on a silicon microring resonator. OPTICS EXPRESS 2016; 24:24105-24116. [PMID: 27828241 DOI: 10.1364/oe.24.024105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We demonstrate that enhanced linear absorption coefficient (LAC) of in-plane monolayer graphene is determined by the optical transmission spectra of a graphene layer coated symmetrically coupled add-drop silicon microring resonator (SC-ADSMR), of which the value is around 0.23 dB/µm. In contrast to the traditional cut-back method, the measured results aren't dependent on the coupling efficiency between the fiber tip and the waveguide. Moreover, precisely evaluation of graphene layer coated silicon microring resonator (SMR) is crucial for future optoelectronic devices with compact footprint and low power consumption.
Collapse
|
27
|
Huang BH, Lu WB, Li XB, Wang J, Liu ZG. Waveguide-coupled hybrid plasmonic modulator based on graphene. APPLIED OPTICS 2016; 55:5598-5602. [PMID: 27463912 DOI: 10.1364/ao.55.005598] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this paper, we propose a low-transmission-loss, high-speed, graphene-based electro-absorption modulator with a hybrid plasmonic waveguide at 1.55 μm. In the proposed device, double-layer graphene is placed on top of the horizontal hybrid plasmonic waveguide to enhance the light-graphene interaction. The adjustment of the in-plane permittivity of the anisotropy graphene causes a significant modulation of the absorption at the operating bandwidth of 0.4 THz, with modulation length of 8.5 μm and modulator footprint of 1.6 μm2. A taper silicon coupler is used for waveguide coupling, and 80% coupling efficiency is achieved. In addition, the modulation potential on a smaller footprint is further shown.
Collapse
|
28
|
Schall D, Mohsin M, Sagade AA, Otto M, Chmielak B, Suckow S, Giesecke AL, Neumaier D, Kurz H. Infrared transparent graphene heater for silicon photonic integrated circuits. OPTICS EXPRESS 2016; 24:7871-7878. [PMID: 27137229 DOI: 10.1364/oe.24.007871] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Thermo-optical tuning of the refractive index is one of the pivotal operations performed in integrated silicon photonic circuits for thermal stabilization, compensation of fabrication tolerances, and implementation of photonic operations. Currently, heaters based on metal wires provide the temperature control in the silicon waveguide. The strong interaction of metal and light, however, necessitates a certain gap between the heater and the photonic structure to avoid significant transmission loss. Here we present a graphene heater that overcomes this constraint and enables an energy efficient tuning of the refractive index. We achieve a tuning power as low as 22 mW per free spectral range and fast response time of 3 µs, outperforming metal based waveguide heaters. Simulations support the experimental results and suggest that for graphene heaters the spacing to the silicon can be further reduced yielding the best possible energy efficiency and operation speed.
Collapse
|
29
|
Zhang H, Healy N, Shen L, Huang CC, Hewak DW, Peacock AC. Enhanced all-optical modulation in a graphene-coated fibre with low insertion loss. Sci Rep 2016; 6:23512. [PMID: 27001353 PMCID: PMC4802326 DOI: 10.1038/srep23512] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/03/2016] [Indexed: 11/29/2022] Open
Abstract
Graphene is a highly versatile two-dimensional material platform that offers exceptional optical and electrical properties. Of these, its dynamic conductivity and low effective carrier mass are of particular interest for optoelectronic applications as they underpin the material's broadband nonlinear optical absorption and ultra-fast carrier mobility, respectively. In this paper, we utilize these phenomena to demonstrate a high-speed, in-fibre optical modulator developed on a side-polished optical fibre platform. An especially low insertion loss (<1 dB) was achieved by polishing the fibre to a near atomically smooth surface (<1 nm RMS), which minimized scattering and ensured excellent contact between the graphene film and the fibre. In order to enhance the light-matter interaction, the graphene film is coated with a high index polyvinyl butyral layer, which has the added advantage of acting as a barrier to the surrounding environment. Using this innovative approach, we have fabricated a robust and stable all-fibre device with an extinction ratio as high as 9 dB and operation bandwidth of 0.5 THz. These results represent a key step towards the integration of low-dimensional materials within standard telecoms networks.
Collapse
Affiliation(s)
- Haojie Zhang
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Noel Healy
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK
- Emerging Technology and Materials Group, School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Li Shen
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Chung Che Huang
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Daniel W. Hewak
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Anna C. Peacock
- Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| |
Collapse
|
30
|
Dynamically reconfigurable nanoscale modulators utilizing coupled hybrid plasmonics. Sci Rep 2015; 5:12313. [PMID: 26189813 PMCID: PMC4507171 DOI: 10.1038/srep12313] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 06/25/2015] [Indexed: 11/08/2022] Open
Abstract
The balance between extinction ratio (ER) and insertion loss (IL) dictates strict trade-off when designing travelling-wave electro-optic modulators. This in turn entails significant compromise in device footprint (L3dB) or energy consumption (E). In this work, we report a nanoscale modulator architecture that alleviates this trade-off while providing dynamic reconfigurability that was previously unattainable. This is achieved with the aide of three mechanisms: (1) Utilization of epsilon-near-zero (ENZ) effect, which maximizes the attainable attenuation that an ultra-thin active material can inflict on an optical mode. (2) Non-resonant coupled-plasmonic structure which supports modes with athermal long-range propagation. (3) Triode-like biasing scheme for flexible manipulation of field symmetry and subsequently waveguide attributes. By electrically inducing indium tin oxide (ITO) to be in a local ENZ state, we show that a Si/ITO/HfO2/Al/HfO2/ITO/Si coupled-plasmonic waveguide can provide amplitude modulation with ER = 4.83 dB/μm, IL = 0.03 dB/μm, L3dB = 622 nm, and E = 14.8 fJ, showing at least an order of magnitude improvement in modulator figure-of-merit and power efficiency compared to other waveguide platforms. Employing different biasing permutations, the same waveguide can then be reconfigured for phase and 4-quadrature-amplitude modulation, with actively device length of only 5.53 μm and 17.78 μm respectively.
Collapse
|
31
|
Sun L, Jiang C. Electrically controllable single-photon switch based on graphene. APPLIED OPTICS 2015; 54:5650-5656. [PMID: 26193009 DOI: 10.1364/ao.54.005650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose an electrically controllable single-photon switch that consists of a graphene nanoribbon side-coupled to a dynamically modulated graphene nanodisk. With a harmonic modulation of graphene conductivity induced by the gate voltage, interband photonic transition between two eigenstates of the nanodisk is introduced, which leads to extraordinary single-photon transport properties such as electromagnetically induced transparency-like phenomena. This effect is utilized to realize a highly efficient single-photon switch. With properly designed parameters, numerical results show that an extinction ratio of up to 20.8 dB can be achieved. The influence of the coupling strength between nanoribbon and nanodisk, the coupling strength between two eigenstates of the nanodisk, and dissipations in the nanodisk are also investigated in this paper.
Collapse
|
32
|
Experimental verification of electro-refractive phase modulation in graphene. Sci Rep 2015; 5:10967. [PMID: 26061415 PMCID: PMC4462031 DOI: 10.1038/srep10967] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 05/12/2015] [Indexed: 11/09/2022] Open
Abstract
Graphene has been considered as a promising material for opto-electronic devices, because of its tunable and wideband optical properties. In this work, we demonstrate electro-refractive phase modulation in graphene at wavelengths from 1530 to 1570 nm. By integrating a gated graphene layer in a silicon-waveguide based Mach-Zehnder interferometer, the key parameters of a phase modulator like change in effective refractive index, insertion loss and absorption change are extracted. These experimentally obtained values are well reproduced by simulations and design guidelines are provided to make graphene devices competitive to contemporary silicon based phase modulators for on-chip applications.
Collapse
|
33
|
Luo S, Wang Y, Tong X, Wang Z. Graphene-based optical modulators. NANOSCALE RESEARCH LETTERS 2015; 10:199. [PMID: 26034412 PMCID: PMC4444650 DOI: 10.1186/s11671-015-0866-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/17/2015] [Indexed: 05/22/2023]
Abstract
Optical modulators (OMs) are a key device in modern optical systems. Due to its unique optical properties, graphene has been recently utilized in the fabrication of optical modulators, which promise high performance such as broadband response, high modulation speed, and high modulation depth. In this paper, the latest experimental and theoretical demonstrations of graphene optical modulators (GOMs) with different structures and functions are reviewed. Particularly, the principles of electro-optical and all-optical modulators are illustrated. Additionally, the limitation of GOMs and possible methods to improve performance and practicability are discussed. At last, graphene terahertz modulators (GTMs) are introduced.
Collapse
Affiliation(s)
- Siyuan Luo
- />Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054 People’s Republic of China
- />State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Microelectronics and Solid-State Electronics, University of Electronic Science and Technology of China, Chengdu, 610054 People’s Republic of China
| | - Yanan Wang
- />Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054 People’s Republic of China
| | - Xin Tong
- />Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054 People’s Republic of China
| | - Zhiming Wang
- />Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054 People’s Republic of China
- />State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Microelectronics and Solid-State Electronics, University of Electronic Science and Technology of China, Chengdu, 610054 People’s Republic of China
| |
Collapse
|
34
|
Subbaraman H, Xu X, Hosseini A, Zhang X, Zhang Y, Kwong D, Chen RT. Recent advances in silicon-based passive and active optical interconnects. OPTICS EXPRESS 2015; 23:2487-2510. [PMID: 25836116 DOI: 10.1364/oe.23.002487] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Silicon photonics has experienced phenomenal transformations over the last decade. In this paper, we present some of the notable advances in silicon-based passive and active optical interconnect components, and highlight some of our key contributions. Light is also cast on few other parallel technologies that are working in tandem with silicon-based structures, and providing unique functions not achievable with any single system acting alone. With an increasing utilization of CMOS foundries for silicon photonics fabrication, a viable path for realizing extremely low-cost integrated optoelectronics has been paved. These advances are expected to benefit several application domains in the years to come, including communication networks, sensing, and nonlinear systems.
Collapse
|
35
|
Sun L, Tang B, Jiang C. Enhanced spontaneous emission of mid-infrared dipole emitter in double-layer graphene waveguide. OPTICS EXPRESS 2014; 22:26487-26497. [PMID: 25401800 DOI: 10.1364/oe.22.026487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a double-layer graphene waveguide which can greatly enhance spontaneous emission rate (SER) of electric dipole emitter placed in it. With properly designed parameters, numerical results show that SER enhanced factors as high as 2.127 × 10(6) and 1.941 × 10(5) can be achieved for two different dipole moment orientations, respectively. The influences of waveguide thickness, existence of supporting layer and gating electrodes, location offset of the emitter and dipole moment orientation on spontaneous emission enhancement are also studied in this paper. To the best of our knowledge, this is the first numerical study of SER enhanced effect in complicated graphene structure.
Collapse
|