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Interlayer Slope Waveguide Coupler for Multilayer Chalcogenide Photonics. PHOTONICS 2022. [DOI: 10.3390/photonics9020094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The interlayer coupler is one of the critical building blocks for optical interconnect based on multilayer photonic integration to realize light coupling between stacked optical waveguides. However, commonly used coupling strategies, such as evanescent field coupling, usually require a close distance, which could cause undesired interlayer crosstalk. This work presents a novel interlayer slope waveguide coupler based on a multilayer chalcogenide glass photonic platform, enabling light to be directly guided from one layer to another with a large interlayer gap (1 µm), a small footprint (6 × 1 × 0.8 µm3), low propagation loss (0.2 dB at 1520 nm), low device processing temperature, and a high bandwidth, similar to that in a straight waveguide. The proposed interlayer slope waveguide coupler could further promote the development of advanced multilayer integration in 3D optical communications systems.
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Gericke E, Melskens J, Wendt R, Wollgarten M, Hoell A, Lips K. Quantification of Nanoscale Density Fluctuations in Hydrogenated Amorphous Silicon. PHYSICAL REVIEW LETTERS 2020; 125:185501. [PMID: 33196241 DOI: 10.1103/physrevlett.125.185501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
The nanostructure of hydrogenated amorphous silicon (a-Si∶H) is studied by a combination of small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS) with a spatial resolution of 0.8 nm. The a-Si∶H materials were deposited using a range of widely varied conditions and are representative for this class of materials. We identify two different phases that are embedded in the a-Si∶H matrix and quantified both according to their scattering cross sections. First, 1.2 nm sized voids (multivacancies with more than 10 missing atoms) which form a superlattice with 1.6 nm void-to-void distance are detected. The voids are found in concentrations as high as 6×10^{19} cm^{-3} in a-Si∶H material that is deposited at a high rate. Second, dense ordered domains (DOD) that are depleted of hydrogen with 1 nm average diameter are found. The DOD tend to form 10-15 nm sized aggregates and are largely found in all a-Si∶H materials considered here. These quantitative findings make it possible to understand the complex correlation between structure and electronic properties of a-Si∶H and directly link them to the light-induced formation of defects. Finally, a structural model is derived, which verifies theoretical predictions about the nanostructure of a-Si∶H.
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Affiliation(s)
- Eike Gericke
- Helmholtz-Zentrum Berlin, Institute for Nanospectroscopy, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
- Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Jimmy Melskens
- Eindhoven University of Technology, Department of Applied Physics, PO Box 513, 5600 MB Eindhoven, Netherlands
| | - Robert Wendt
- Helmholtz-Zentrum Berlin, Institute for Nanospectroscopy, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Markus Wollgarten
- Helmholtz-Zentrum Berlin, Institute Solar Fuels, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Armin Hoell
- Helmholtz-Zentrum Berlin, Institute for Nanospectroscopy, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Klaus Lips
- Helmholtz-Zentrum Berlin, Department Spins in Energy Conversion and Quantum Information Science (ASPIN), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
- Freie Universität Berlin, Department of Physics, Arnimallee 14, 14195 Berlin, Germany
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Zhang Z, Huang B, Zhang Z, Cheng C, Bai B, Gao T, Xu X, Gu W, Zhang L, Chen H. Broadband High-Efficiency Grating Couplers for Perfectly Vertical Fiber-to-Chip Coupling Enhanced by Fabry-Perot-like Cavity. MICROMACHINES 2020; 11:mi11090859. [PMID: 32957465 PMCID: PMC7569773 DOI: 10.3390/mi11090859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/09/2020] [Accepted: 09/16/2020] [Indexed: 11/16/2022]
Abstract
We propose a broadband high-efficiency grating coupler for perfectly vertical fiber-to-chip coupling. The up-reflection is reduced, hence enhanced coupling efficiency is achieved with the help of a Fabry-Perot-like cavity composed of a silicon nitride reflector and the grating itself. With the theory of the Fabry-Perot cavity, the dimensional parameters of the coupler are investigated. With the optimized parameters, up-reflection in the C-band is reduced from 10.6% to 5%, resulting in an enhanced coupling efficiency of 80.3%, with a 1-dB bandwidth of 58 nm, which covers the entire C-band. The minimum feature size of the proposed structure is over 219 nm, which makes our design easy to fabricate through 248 nm deep-UV lithography, and lowers the fabrication cost. The proposed design has potential in efficient and fabrication-tolerant interfacing applications, between off-chip light sources and integrated chips that can be mass-produced.
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Affiliation(s)
- Zan Zhang
- School of Electronics and Control Engineering, Chang’an University, Xi’an 710064, China; (B.B.); (T.G.); (X.X.); (W.G.); (L.Z.)
- Correspondence:
| | - Beiju Huang
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (B.H.); (C.C.); (H.C.)
| | - Zanyun Zhang
- School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin 300387, China;
| | - Chuantong Cheng
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (B.H.); (C.C.); (H.C.)
| | - Bing Bai
- School of Electronics and Control Engineering, Chang’an University, Xi’an 710064, China; (B.B.); (T.G.); (X.X.); (W.G.); (L.Z.)
| | - Tianxi Gao
- School of Electronics and Control Engineering, Chang’an University, Xi’an 710064, China; (B.B.); (T.G.); (X.X.); (W.G.); (L.Z.)
| | - Xiaobo Xu
- School of Electronics and Control Engineering, Chang’an University, Xi’an 710064, China; (B.B.); (T.G.); (X.X.); (W.G.); (L.Z.)
| | - Wenping Gu
- School of Electronics and Control Engineering, Chang’an University, Xi’an 710064, China; (B.B.); (T.G.); (X.X.); (W.G.); (L.Z.)
| | - Lin Zhang
- School of Electronics and Control Engineering, Chang’an University, Xi’an 710064, China; (B.B.); (T.G.); (X.X.); (W.G.); (L.Z.)
| | - Hongda Chen
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (B.H.); (C.C.); (H.C.)
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