scholarly journals Grating Couplers on Silicon Photonics: Design Principles, Emerging Trends and Practical Issues

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 666 ◽  
Author(s):  
Lirong Cheng ◽  
Simei Mao ◽  
Zhi Li ◽  
Yaqi Han ◽  
H. Fu
Keyword(s):  
Optical Fibers ◽  
Silicon Photonics ◽  
High Performance ◽  
Low Cost ◽  
Coupling Efficiency ◽  
Polarization Sensitivity ◽  
Grating Couplers ◽  
Space Optics ◽  
Wavelength Sensitivity ◽  
Out Of Plane

Silicon photonics is an enabling technology that provides integrated photonic devices and systems with low-cost mass manufacturing capability. It has attracted increasing attention in both academia and industry in recent years, not only for its applications in communications, but also in sensing. One important issue of silicon photonics that comes with its high integration density is an interface between its high-performance integrated waveguide devices and optical fibers or free-space optics. Surface grating coupler is a preferred candidate that provides flexibility for circuit design and reduces effort for both fabrication and alignment. In the past decades, considerable research efforts have been made on in-plane grating couplers to address their insufficiency in coupling efficiency, wavelength sensitivity and polarization sensitivity compared with out-of-plane edge-coupling. Apart from improved performances, new functionalities are also on the horizon for grating couplers. In this paper, we review the current research progresses made on grating couplers, starting from their fundamental theories and concepts. Then, we conclude various methods to improve their performance, including coupling efficiency, polarization and wavelength sensitivity. Finally, we discuss some emerging research topics on grating couplers, as well as practical issues such as testing, packaging and promising applications.

Electrostatic bellow muscle actuators and energy harvesters that stack up

2021 ◽  
Vol 6 (51) ◽  
pp. eaaz5796
Author(s):  
I. D. Sîrbu ◽  
G. Moretti ◽  
G. Bortolotti ◽  
M. Bolignari ◽  
S. Diré ◽  
...  
Keyword(s):  
High Performance ◽  
High Reliability ◽  
Low Cost ◽  
Artificial Muscle ◽  
Pressure Head ◽  
Robotic Systems ◽  
Maximum Pressure ◽  
Term Operation ◽  
Energy Harvesters ◽  
Out Of Plane

Future robotic systems will be pervasive technologies operating autonomously in unknown spaces that are shared with humans. Such complex interactions make it compulsory for them to be lightweight, soft, and efficient in a way to guarantee safety, robustness, and long-term operation. Such a set of qualities can be achieved using soft multipurpose systems that combine, integrate, and commute between conventional electromechanical and fluidic drives, as well as harvest energy during inactive actuation phases for increased energy efficiency. Here, we present an electrostatic actuator made of thin films and liquid dielectrics combined with rigid polymeric stiffening elements to form a circular electrostatic bellow muscle (EBM) unit capable of out-of-plane contraction. These units are easy to manufacture and can be arranged in arrays and stacks, which can be used as a contractile artificial muscle, as a pump for fluid-driven soft robots, or as an energy harvester. As an artificial muscle, EBMs of 20 to 40 millimeters in diameter can exert forces of up to 6 newtons, lift loads over a hundred times their own weight, and reach contractions of over 40% with strain rates over 1200% per second, with a bandwidth over 10 hertz. As a pump driver, these EBMs produce flow rates of up to 0.63 liters per minute and maximum pressure head of 6 kilopascals, whereas as generator, they reach a conversion efficiency close to 20%. The compact shape, low cost, simple assembling procedure, high reliability, and large contractions make the EBM a promising technology for high-performance robotic systems.

Significant texture improvement in single-crystalline-like materials on low-cost flexible metal foils through growth of silver thin films

2019 ◽  
Vol 52 (4) ◽  
pp. 898-902 ◽  
Author(s):  
Yongkuan Li ◽  
Sicong Sun ◽  
Ying Gao ◽  
Yao Yao ◽  
Eduard Galstyan ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Single Crystalline ◽  
Metal Foils ◽  
Ion Beam Assisted Deposition ◽  
Out Of Plane ◽  
Flexible Metal ◽  
Ag Film

Low texture spreads of single-crystalline-like materials are critical for high performance of low-cost flexible semiconductors and second-generation high-temperature superconductors based on metal foils. For texture improvement, a single-crystalline-like Ag film is epitaxially grown on an ion-beam-assisted deposition TiN substrate using magnetron sputtering. Ultra-low texture spreads are found in the thin Ag film (∼330 nm), with an out-of-plane texture spread (Δω) of ∼1.03° and an in-plane texture spread (Δϕ) of ∼1.34°. Compared with the texture spreads of the TiN substrate, Δω and Δϕ of the Ag film are reduced by ∼42 and ∼79%, respectively. Applying this Ag buffer, the texture spreads of a single-crystalline-like Ge film are reduced by ∼37% (Δω) and ∼36% (Δϕ). Factors contributing to the texture improvement by Ag are studied using single-crystalline-like Ag films with various thicknesses.

Near-Zero Shift Attachment for Optoelectronic Components

2011 ◽  
Vol 2011 (1) ◽  
pp. 001058-001066
Author(s):  
Roy J. Bourcier
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Coupling Efficiency ◽  
Single Mode ◽  
Optical Coupling ◽  
Free Space Optical ◽  
Optical Elements ◽  
Uv Curable ◽  
Design Concepts ◽  
Process Elements

High performance laser-based optoelectronic devices commonly feature the use of free-space optical coupling between the laser diode and optical elements such as filters, secondary harmonic generators and optical fibers. A critical challenge in the assembly of such components is maintaining the required optical alignment precision during attachment of the optical subcomponents to a common platform. In the case of devices based on single mode waveguides, the post-attach shift must often be held to less than a few hundred nanometers to achieve the desired optical coupling efficiency. Historically, these tight tolerances have required the use of costly post-work operations such as laser hammering or re-bend to achieve performance objectives. Over the course of designing several such optoelectronic components, we have used and developed a variety of design concepts and assembly processes which have allowed us to achieve these demanding tolerances, often without the use of post-work. UV-curable structural adhesives and Nd:YAG laser spot welding have been used, individually and in combination, to perform the required sub-micron optomechanical attachments. Several approaches which have been successfully used will be described and their relative merits will be compared. In addition, key design and process elements which can impact post-attach shift will be discussed.

scholarly journals Novel Low-Loss Fiber-Chip Edge Coupler for Coupling Standard Single Mode Fibers to Silicon Photonic Wire Waveguides

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 79
Author(s):  
Siwei Sun ◽  
Ying Chen ◽  
Yu Sun ◽  
Fengman Liu ◽  
Liqiang Cao
Keyword(s):  
Optical Fibers ◽  
Silicon Photonics ◽  
Coupling Efficiency ◽  
Single Mode ◽  
Spot Size ◽  
Silicon On Insulator ◽  
Multiple Structure ◽  
Silicon Photonic ◽  
Mode Size ◽  
Photonic Wire

Fiber-to-chip optical interconnects is a big challenge in silicon photonics application scenarios such as data centers and optical transmission systems. An edge coupler, compared to optical grating, is appealing to in the application of silicon photonics due to the high coupling efficiency between standard optical fibers (SMF-28) and the sub-micron silicon wire waveguides. In this work, we proposed a novel fiber–chip edge coupler approach with a large mode size for silicon photonic wire waveguides. The edge coupler consists of a multiple structure which was fulfilled by multiple silicon nitride layers embedded in SiO2 upper cladding, curved waveguides and two adiabatic spot size converter (SSC) sections. The multiple structure can allow light directly coupling from large mode size fiber-to-chip coupler, and then the curved waveguides and SSCs transmit the evanescent field to a 220 nm-thick silicon wire waveguide based on the silicon-on-insulator (SOI) platform. The edge coupler, designed for a standard SMF-28 fiber with 8.2 μm mode field diameter (MFD) at a wavelength of 1550 nm, exhibits a mode overlap efficiency exceeding 95% at the chip facet and the overall coupling exceeding 90%. The proposed edge coupler is fully compatible with standard microfabrication processes.

scholarly journals Out-of-Plane Focusing Grating Couplers for Silicon Photonics Integration With Optical MRAM Technology

2020 ◽  
Vol 26 (2) ◽  
pp. 1-8 ◽  
Author(s):  
Hanna Becker ◽  
Clemens J. Kruckel ◽  
Dries Van Thourhout ◽  
Martijn J. R. Heck
Keyword(s):  
Silicon Photonics ◽  
Grating Couplers ◽  
Out Of Plane

scholarly journals Integration of 2D materials on a silicon photonics platform for optoelectronics applications

Nanophotonics ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 1205-1218 ◽  
Author(s):  
Nathan Youngblood ◽  
Mo Li
Keyword(s):  
Optical Properties ◽  
Data Storage ◽  
Silicon Photonics ◽  
High Performance ◽  
2D Materials ◽  
Covalent Bonds ◽  
Networks On Chip ◽  
Out Of Plane ◽  
Telecom Networks ◽  
On Chip

AbstractOwing to enormous growth in both data storage and the demand for high-performance computing, there has been a major effort to integrate telecom networks on-chip. Silicon photonics is an ideal candidate, thanks to the maturity and economics of current CMOS processes in addition to the desirable optical properties of silicon in the near IR. The basics of optical communication require the ability to generate, modulate, and detect light, which is not currently possible with silicon alone. Growing germanium or III/V materials on silicon is technically challenging due to the mismatch between lattice constants and thermal properties. One proposed solution is to use two-dimensional materials, which have covalent bonds in-plane, but are held together by van der Waals forces out of plane. These materials have many unique electrical and optical properties and can be transferred to an arbitrary substrate without lattice matching requirements. This article reviews recent progress toward the integration of 2D materials on a silicon photonics platform for optoelectronic applications.

scholarly journals Nanograting-Enhanced Optical Fibers for Visible and Infrared Light Collection at Large Input Angles

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 295
Author(s):  
Ning Wang ◽  
Matthias Zeisberger ◽  
Uwe Hübner ◽  
Markus A. Schmidt
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Large Angle ◽  
Coupling Efficiency ◽  
Numerical Aperture ◽  
Infrared Light ◽  
Light Collection ◽  
High Performance Fiber ◽  
Visible Wavelengths ◽  
Quantum Technology

The efficient incoupling of light into particular fibers at large angles is essential for a multitude of applications; however, this is difficult to achieve with commonly used fibers due to low numerical aperture. Here, we demonstrate that commonly used optical fibers functionalized with arrays of metallic nanodots show substantially improved large-angle light-collection performances at multiple wavelengths. In particular, we show that at visible wavelengths, higher diffraction orders contribute significantly to the light-coupling efficiency, independent of the incident polarization, with a dominant excitation of the fundamental mode. The experimental observation is confirmed by an analytical model, which directly suggests further improvement in incoupling efficiency through the use of powerful nanostructures such as metasurface or dielectric gratings. Therefore, our concept paves the way for high-performance fiber-based optical devices and is particularly relevant within the context of endoscopic-type applications in life science and light collection within quantum technology.

scholarly journals Silicon/2D-material photodetectors: from near-infrared to mid-infrared

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Chaoyue Liu ◽  
Jingshu Guo ◽  
Laiwen Yu ◽  
Jiang Li ◽  
Ming Zhang ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Silicon Photonics ◽  
High Performance ◽  
Near Infrared ◽  
Low Cost ◽  
Two Dimensional ◽  
Wavelength Band ◽  
Mid Infrared ◽  
Two Dimensional Materials ◽  
Flexible Integration

AbstractTwo-dimensional materials (2DMs) have been used widely in constructing photodetectors (PDs) because of their advantages in flexible integration and ultrabroad operation wavelength range. Specifically, 2DM PDs on silicon have attracted much attention because silicon microelectronics and silicon photonics have been developed successfully for many applications. 2DM PDs meet the imperious demand of silicon photonics on low-cost, high-performance, and broadband photodetection. In this work, a review is given for the recent progresses of Si/2DM PDs working in the wavelength band from near-infrared to mid-infrared, which are attractive for many applications. The operation mechanisms and the device configurations are summarized in the first part. The waveguide-integrated PDs and the surface-illuminated PDs are then reviewed in details, respectively. The discussion and outlook for 2DM PDs on silicon are finally given.

Heterogeneous Integration of Photonic Integrated Circuits Using 3D Assembly Techniques: Silicon Technology and Packaging

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 002057-002086 ◽  
Author(s):  
Yann Lamy ◽  
Haykel Ben Jamaa ◽  
Hughes Metras ◽  
Stéphane Bernabé ◽  
Sylvie Menezo ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Optical Fibers ◽  
Silicon Photonics ◽  
Low Cost ◽  
Heterogeneous Integration ◽  
3D Integration ◽  
Continuous Growth ◽  
Silicon Technology ◽  
The Past ◽  
The Impact

The large internet companies' investments indicate an ongoing increase of data-based business volume through the next decades with the rise of the internet of things and the continuous growth of communication and data facilities. The two-figure yearly growth rate of exchanged data volume within data centers is challenging the actual short distance communication paradigms. With datacenter architectures getting larger and “flatter”, the availability of high bandwidth, low power and low cost optical links ranging from less than 1 meter to 1 kilometer is a key issue. It is therefore expected that today's 10 Gb/s transceiver data rate soon increase to 28Gb/s, 40 Gb/s and beyond. For such a channel bandwidth, the copper-based wires are no longer suitable in terms of cost, power and bandwidth density. Optical interconnects are expected to replace copper for short distances below 500 m and down to 1 m within servers and between servers of the same data center. They exhibit much higher scalability and flexibility in terms of bandwidth, reach and lower energy consumption down to 1 pJ/b and below. The integration of optical transceivers close to the computational logic is therefore becoming more and more attractive. The enabling technology for optical interconnect is silicon photonics which is maturing and leveraging the well-established knowledge coming from silicon technology. We today have a complete set of silicon photonics technology modules that cover passive components including multiplexers/demultiplexers, coupling functions, photodetectors, modulators and integrated laser sources. Given the constraints coming from the supply chain, we consider a heterogeneous integration of the photonics (PIC) and the electrical integrated circuits (EIC) within a single package, differentiating from a co-integration of both of them on a single die demonstrated in the past, which is not a viable nor scalable option from the economical point of view. Thereby we leverage our expertise in the 3D integration field, and we use a full set of mature technology modules including through-silicon vias (TSV), wafer thinning and micro-bumping. These modules have only been used in the past within electrical circuits, but their implantation in photonics chips has no showstoppers. The 3D integration enables a stacking of the electrical drivers in the EIC die on top of the photodiodes and modulators in the PIC die. The small micro-bump size reduces the parasitic capacitances and enables an optimized electro-optical co-design. The TSV enable the connection of the stack with the rest of the package and to the second-level interconnect with low inductive losses, thus boosting the system performance. The advanced 3D packaging technique also enables the alignment and attachment of the optical fibers using silicon micro-ferrules. Today's active alignment techniques for optical coupling are time-consuming and expensive, and not compatible with usual micro-electronics techniques. The ongoing development of silicon micro-ferrules with mechanical micro-bumps enables a compatible assembly of the optical plugs with the remaining system and a quick assembly process with standard pick-and-place equipment. The paper will introduce today's system demand in the data base market and its translation into technology requirements. It will then survey our silicon photonics technology modules and actual demonstrations. We will then introduce the packaging constraints and the impact of 3D integration on the system assembly. Finally, we will present our advances in terms of packaging of optical micro-connectors.

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