1,721,189 research outputs found
Localised tuneable composition single crystal silicon-germanium-on-insulator for low cost devices
No full textData for the paper Littlejohns, Callum, Dominguez Bucio, Thalia, Nedeljkovic, Milos, Mashanovich, Goran, Reed, Graham and Gardes, Frederic (2016) Localised tuneable composition single crystal silicon-germanium-on-insulator for low cost devices. Advances in Materials Science and Engineering</span
Dataset for Germanium Micro-Gears as Vertically-Emitting Light Sources
No full textData underpinning the publication 'Germanium vertically light-emitting micro-gears generating orbital angular momentum' by Saito, Shinichi; Al-Attili, Abderlrahman Z.; Burt, Daniel; Li, Zuo; Higashitarumizu, Naoki; Gardes, Frederic; Oda, Katsuya; Ishikawa, Yasuhiko published in Optics Express.</span
Dataset for: GeSi Franz-Keldysh Modulator for Silicon Photonic Integrated Circuits
No full textRaw data for the doctoral thesis 'GeSi Franz-Keldysh Modulator for Silicon Photonic Integrated Circuits'.</span
GaN/Si hybrid integrated photonic platform in UV-blue light region
No full textPhotonic integration platforms working in the UV-blue light wavelength range, with the advantages of a smaller footprint and a larger bandwidth compared with their infrared counterparts, hold the promise for the applications in augmented reality (AR)/virtual reality (VR) systems, light detection and ranging (Lidar), visible light communications, quantum photonic chips, bio-photonic chips, and so on. In order to fabricate such an integrated platform, both GaN based emitters and the passive Si photonic devices are required. In this emerging research area, there are few preliminary works in the emitters and low-loss waveguides in UV-blue wavelength range, [1,2] the established parameters for design a full UV-blue integrated platform is still missing. In this work, we proposed and fabricated a hybrid UV-blue photonic integrated platform which consists of a Distributed Bragg Reflector enhanced light emitting diode (DBR-LED) flip-chip bonded to Si photonic circuits. The latter is comprised of Al2O3 grating couplers and optical tapers with optimized parameters fabricated on Si to effectively couple the light from the DBR-LED (with improved emission directivity and brightness) to the waveguides, which deliver optical signals to the rest areas in the integrated photonic circuits. Regarding the active emitter, SiN/SiO2 DBRs were fabricated on a 450 nm blue LED with 10 pairs in the back side and 5 pairs in the front side. The DBR-LED exhibits a 10 times higher emission intensity in the vertical emission direction and a reduced linewidth from 26 to 17 nm. The major Fabry–Pérot peak is defined at 446 nm. For the passive photonics, we adopted atomic layer deposited (ALD) Al2O3 waveguide-based devices as it is demonstrated an ultra-low propagation loss of <3 dB/cm in the UV and <0.3 dB/cm in the blue region. The dimension of Al2O3 waveguide is 400 nm in width and 85nm in the thickness, supporting single mode with wavelengths from 250 to 490 nm, with a simulated propagation loss less than 1dB/cm. Vertical grating couplers with a period/duty cycle of 600 nm/0.27 were fabricated with an expected coupling efficiency of 6%. Following that it is a trapezoidal optical taper with width and length of 4 and 10 μm to generate a pure single mode in the waveguides. As the first demonstration in GaN/Si UV-blue integrated photonics with well-defined parameters in both active emitters and passive devices, we believe our work is instructive to the future work in GaN/Si photonic integrated systems. <br/
Designs of Silicon Nitride Slot Waveguide Modulators with Electro-Optic Polymer and the Effect of Induced Charges in Si-Substrate on Their Performance
No full textDimensional parameters are optimized comparing stoichiometric and Si-rich silicon nitride-based push-pull modulators using a slot waveguide structure, electro-optic polymer cladding, and in-plane ground-signal-ground electrode. An optical power confinement in slot spacing is examined for choosing the optimal device parameters for wavelength of 1550nm. The electrical simulations are set to calculate an asymmetric spatial distribution of poling efficiency and modulating refractive index change in polymer. The influence of carrier charge in Si-substrate is also considered. The voltage-length products as well as the poling efficiency of Si-rich SiN are calculated as 1.47 V·cm and 0.74 respectively for a polymer with a γ_(33,bulk) of 100 pm/V. For the selected polymer the calculated efficiency comparable to standard silicon based plasma dispersion depletion modulators. The efficiency can be increased more than two times for demonstrated polymers with a γ_(33,bulk) of ~230. Low metal absorption loss of ~ 1dB/cm can be achieved from the optimal designed device. Comparing to the conventional simulation method without Si-substrate effect, a more accurate simulation method is also presented in this work
Dataset supporting the University of Southampton Doctoral Thesis "Passive and Active Tunability of the Silicon Nitride platform"
No full text Dataset supporting the University of Southampton Doctoral Thesis "Passive and active tunability of the silicon nitride platform"
This dataset contains: numerical data used to create the graphs present in the thesis, all in .csv format. The data includes simulation, material analysis, optical and electrical characterisation of devices.
The data is embargoed to 30/04/2025</span
Highly efficient dual‑level grating couplers for silicon nitride photonics
No full textWe propose and numerically demonstrate a versatile strategy that allows designing highly efficient dual-level grating couplers in different silicon nitride-based photonic platforms. The proposed technique, which can generally be applied to an arbitrary silicon nitride film thickness, is based on the simultaneous optimization of two grating coupler levels to obtain high directionality and grating-fibre mode matching at the same time. This is achieved thanks to the use of two different linear apodizations, with opposite signs, applied to the two grating levels, whose design parameters are determined by using a particle swarm optimization method. Numerical simulations were carried out considering different silicon nitride platforms with 150, 300, 400 and 500 nm thicknesses and initially employing silicon as the material for the top level grating coupler. The use of Si-rich silicon nitride with a refractive index in the range 2.7–3.3 for the top layer material enabled to obtain similar performance (coupling efficiency exceeding − 0.45 dB for the 400 nm thick silicon nitride platform) with relaxed fabrication tolerances. To the best of our knowledge, these numerical results represent the best performance ever reported in the literature for silicon nitride grating couplers without the use of any back-reflector
Group IV light sources to enable the convergence of photonics and electronics
No full textGroup IV lasers are expected to revolutionize chip-to-chip optical communications in terms of cost, scalability, yield, and compatibility to the existing infrastructure of silicon industries for mass production. Here, we review the current state-of-the-art developments of silicon and germanium light sources toward monolithic integration. Quantum confinement of electrons and holes in nanostructures has been the primary route for light emission from silicon, and we can use advanced silicon technologies using top-down patterning processes to fabricate these nanostructures, including fin-type vertical multiple-quantum-wells. Moreover, the electromagnetic environment can also be manipulated in a photonic crystal nanocavity to enhance the efficiency of light extraction and emission by the Purcell effect. Germanium is also widely investigated as an active material in Group IV photonics, and novel epitaxial growth technologies are being developed to make a high quality germanium layer on a silicon substrate.To develop a practical germanium laser, various technologies are employed for tensile-stress engineering and high electron doping to compensate the indirect valleys in the conduction band. These challenges are aiming to contribute toward the convergence of electronics and photonics on a silicon chip
Athermal silicon nitride angled MMI wavelength division (de)multiplexers for the near-infrared
No full textWDM components fabricated on the silicon-on-insulator platform have transmission characteristics that are sensitive to dimensional errors and temperature variations due to the high refractive index and thermo-optic coefficient of Si, respectively. We propose the use of NH3-free SiNx layers to fabricate athermal (de)multiplexers based on angled multimode interferometers (AMMI) in order to achieve good spectral responses with high tolerance to dimensional errors. With this approach we have shown that stoichiometric and N-rich SiNx layers can be used to fabricate AMMIs with cross-talk<30dB, insertion loss <2.5dB, sensitivity to dimensional errors <120pm/nm, and wavelength shift <10pm/°C
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