Compact efficient broadband grating coupler for silicon-on-insulator waveguides.
TL;DR: A high-efficiency broadband grating coupler for coupling between silicon-on-insulator (SOI) waveguides and optical fibers and the size of the grooves is optimized numerically.
Abstract: We have designed a high-efficiency broadband grating coupler for coupling between silicon-on-insulator (SOI) waveguides and optical fibers. The grating is only 13 µm long and 12 µm wide, and the size of the grooves is optimized numerically. For TE polarization the coupling loss to single-mode fiber is below 1 dB over a 35-nm wavelength range when using SOI with a two-pair bottom reflector. The tolerances to fabrication errors are also calculated.
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TL;DR: In this paper, a grating coupler approach was proposed to improve the coupling efficiency of nanophotonic waveguides and a single-mode fiber in photonic circuits.
Abstract: Nanophotonic waveguides and components are promising for use in the large-scale integration of photonic circuits. Coupling light between nanophotonic waveguides and a single-mode fiber is an important problem and many different solutions have been proposed and demonstrated in recent years. In this paper, we discuss a grating coupler approach. Grating couplers can be placed anywhere on a circuit and can easily be integrated. We have experimentally demonstrated >30% coupling efficiency with a 1 dB bandwidth of 40 nm on standard wafers. Theoretically, the coupling efficiency can be improved to >90% using an optimized grating design and layer stack. The fabrication of the couplers in silicon-on-insulator and in indium phosphide membranes is also discussed.
729 citations
TL;DR: This work reports the direct detection and exploitation of transverse optical forces in an integrated silicon photonic circuit through an embedded nanomechanical resonator, which enables all-optical operation of nanitechanical systems on a CMOS (complementary metal-oxide-semiconductor)-compatible platform, with substantial bandwidth and design flexibility compared to conventional electrical-based schemes.
Abstract: The force exerted by photons is of fundamental importance in light-matter interactions. For example, in free space, optical tweezers have been widely used to manipulate atoms and microscale dielectric particles. This optical force is expected to be greatly enhanced in integrated photonic circuits in which light is highly concentrated at the nanoscale. Harnessing the optical force on a semiconductor chip will allow solid state devices, such as electromechanical systems, to operate under new physical principles. Indeed, recent experiments have elucidated the radiation forces of light in high-finesse optical microcavities, but the large footprint of these devices ultimately prevents scaling down to nanoscale dimensions. Recent theoretical work has predicted that a transverse optical force can be generated and used directly for electromechanical actuation without the need for a high-finesse cavity. However, on-chip exploitation of this force has been a significant challenge, primarily owing to the lack of efficient nanoscale mechanical transducers in the photonics domain. Here we report the direct detection and exploitation of transverse optical forces in an integrated silicon photonic circuit through an embedded nanomechanical resonator. The nanomechanical device, a free-standing waveguide, is driven by the optical force and read out through evanescent coupling of the guided light to the dielectric substrate. This new optical force enables all-optical operation of nanomechanical systems on a CMOS (complementary metal-oxide-semiconductor)-compatible platform, with substantial bandwidth and design flexibility compared to conventional electrical-based schemes.
557 citations
09 May 2012
TL;DR: DSENT, a NoC modeling tool for rapid design space exploration of electrical and opto-electrical networks, is presented and the results show the implications of different technology scenarios and the need to reduce laser and thermal tuning power in a photonic network due to their non-data-dependent nature.
Abstract: With the rise of many-core chips that require substantial bandwidth from the network on chip (NoC), integrated photonic links have been investigated as a promising alternative to traditional electrical interconnects While numerous opto-electronic NoCs have been proposed, evaluations of photonic architectures have thus-far had to use a number of simplifications, reflecting the need for a modeling tool that accurately captures the tradeoffs for the emerging technology and its impacts on the overall network In this paper, we present DSENT, a NoC modeling tool for rapid design space exploration of electrical and opto-electrical networks We explain our modeling framework and perform an energy-driven case study, focusing on electrical technology scaling, photonic parameters, and thermal tuning Our results show the implications of different technology scenarios and, in particular, the need to reduce laser and thermal tuning power in a photonic network due to their non-data-dependent nature
529 citations
Cites background from "Compact efficient broadband grating..."
...Many photonics-augmented architectures have been proposed to address the interconnect scalability issue posed by rapidly rising core-counts, The Corona [4] architecture uses a global 64x64 optical crossbar with shared optical buses employing multiple matching ring modulators on the same waveguide....
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TL;DR: Sub-wavelength structures with a subwavelength pitch have been known since Hertz conducted his first experiments on the polarization of electromagnetic waves as discussed by the authors, and their applications include anti-reflective coatings, polarization rotators, high-efficiency fiber-chip cou-plers, spectrometers, highreflectivity mirrors, athermal waveg- uides, multimode interference couplers.
Abstract: Periodic structures with a sub-wavelength pitch have been known since Hertz conducted his first experiments on the polarization of electromagnetic waves. While the use of these structures in waveguide optics was proposed in the 1990s, it has been with the more recent developments of silicon photonics and high-precision lithography techniques that sub-wavelength structures have found widespread application in the field of pho- tonics. This review first provides an introduction to the physics of sub-wavelength structures. An overview of the applications of sub-wavelength structures is then given including: anti-reflective coatings, polarization rotators, high-efficiency fiber-chip cou- plers, spectrometers, high-reflectivity mirrors, athermal waveg- uides, multimode interference couplers, and dispersion engi- neered, ultra-broadband waveguide couplers among others. Particular attention is paid to providing insight into the design strategies for these devices. The concluding remarks provide an outlook on the future development of sub-wavelength structures and their impact in photonics.
496 citations
TL;DR: A silicon photonics platform that allows monolithic integration with electronic circuits in a CMOS-compatible process is developed and vertical couplers are found to be a superior solution compared to traditional edge-coupling techniques.
Abstract: We have developed a silicon photonics platform that allows monolithic integration with electronic circuits in a CMOS-compatible process. In this platform, vertical couplers are found to be a superior solution compared to traditional edge-coupling techniques. Grating couplers are an essential element in developing the optical wafer-scale test infrastructure, which in turn, enables the development of the photonic device library. The photonic devices were assembled into a 4 × 10 Gb/s transceiver die that also contains modulator drive, control, and receive electronics.
421 citations
Cites background from "Compact efficient broadband grating..."
...This solution has also been demonstrated on other silicon photonics platforms and can achieve coupling losses below 2 dB [18]–[28]....
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References
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Journal Article•
TL;DR: This book describes numerous applications of genetic algorithms to the design and optimization of various low- and high-frequency electromagnetic components and provides a comprehensive list of the up-to-date references applicable to electromagneticdesign problems.
Abstract: From the Publisher:
Authoritative coverage of a revolutionary technique for overcoming problems in electromagnetic design Genetic algorithms are stochastic search procedures modeled on the Darwinian concepts of natural selection and evolution. The machinery of genetic algorithms utilizes an optimization methodology that allows a global search of the cost surface via statistical random processes dictated by the Darwinian evolutionary concept. These easily programmed and readily implemented procedures robustly locate extrema of highly multimodal functions and therefore are particularly well suited to finding solutions to a broad range of electromagnetic optimization problems. Electromagnetic Optimization by Genetic Algorithms is the first book devoted exclusively to the application of genetic algorithms to electromagnetic device design. Compiled by two highly competent and well-respected members of the electromagnetics community, this book describes numerous applications of genetic algorithms to the design and optimization of various low- and high-frequency electromagnetic components. Special features include:
*Introduction by David E. Goldberg, "A Meditation on the Application of Genetic Algorithms"
*Design of linear and planar arrays using genetic algorithms
*Application of genetic algorithms to the design of broadband, wire, and integrated antennas
*Genetic algorithmdriven design of dielectric gratings and frequency-selective surfaces
*Synthesis of magnetostatic devices using genetic algorithms
*Application of genetic algorithms to multiobjective electromagnetic backscattering optimization
*A comprehensive list of the up-to-date references applicable to electromagneticdesign problemsSupplemented with more than 250 illustrations, Electromagnetic Optimization by Genetic Algorithms is a powerful resource for electrical engineers interested in modern electromagnetic designs and an indispensable reference for university researchers.
955 citations
IBM1
TL;DR: The combination of an efficient two-stage coupling scheme and utilization of ultra-long (up to 2mm) photonic crystal waveguides reduces the uncertainty in determining the loss figure to 3dB/cm.
Abstract: We report the design and testing of an SOI-based photonic integrated circuit containing two-dimensional membrane-type photonic crystal waveguides. The circuit comprises spot-size converters to efficiently couple light from a fiber into single-mode strip waveguides and butt-couplers to couple from strip waveguides to photonic crystal waveguides. Each optical interface was optimized to minimize back-reflections and reduce the Fabry-Perot noise. The transmission characteristics of each component are measured and record low propagation losses in photonic crystal waveguides of 24dB/cm are reported. The combination of an efficient two-stage coupling scheme and utilization of ultra-long (up to 2mm) photonic crystal waveguides reduces the uncertainty in determining the loss figure to 3dB/cm.
789 citations
TL;DR: In this paper, an out-of-plane coupler for butt-coupling from fiber to compact planar waveguides is proposed based on a short second-order grating or photonic crystal, etched in a waveguide with a low-index oxide cladding.
Abstract: We have designed and fabricated an out-of-plane coupler for butt-coupling from fiber to compact planar waveguides. The coupler is based on a short second-order grating or photonic crystal, etched in a waveguide with a low-index oxide cladding. The coupler is optimized using mode expansion-based simulations. Simulations using a 2-D model show that up to 74% coupling efficiency between single-mode fiber and a 240-nm-thick GaAs-AlO/sub x/ waveguide is possible. We have measured 19% coupling efficiency on test structures.
687 citations
TL;DR: In this article, a novel integrated mode size converter for single-mode Si wire waveguides is presented, which is constructed with two-dimensional tapered Si waveguide and overlaid high-index polymer waveguide.
Abstract: A novel integrated mode size converter for single-mode Si wire waveguides is presented. The mode size converter is constructed with two-dimensional tapered Si waveguides and overlaid high-index polymer waveguides. We calculated the proposed mode size converter characteristics, and fabricated 1.09 mm length Si wire waveguides with the converters. The measured loss of the mode size converter was 0.8 dB per conversion, and the total insertion loss through the sample with an Si wire waveguide was 3.5 dB.
502 citations
TL;DR: In this paper, a modeling approach for photonic crystal structures and vertical-cavity surface-emitting lasers (VCSELs) is presented based on vectorial eigenmode expansion combined with perfectly matched layer (PML) boundary conditions.
Abstract: We present a modelling approach for photonic crystal structures and vertical-cavity surface-emitting lasers (VCSELs). This method is based on vectorial eigenmode expansion combined with perfectly matched layer (PML) boundary conditions. Compared to other methods, a relatively small computational effort is required, while at the same time accurate results are obtained, even in the presence of strong scattering and diffraction losses.
323 citations