New silicon photonics integration platform enabled by novel micron-scale bends

Even though submicron silicon waveguides have been proposed for dense integration of photonic devices, to date the lightwave circuits on the market mainly rely on waveguides with micron-scale core dimensions. These larger waveguides feature easier fabrication, higher reliability and better interfacing to optical fibres. Single-mode operation with large core dimensions is obtained with low lateral refractive index contrast. Hence, the main limitation in increasing the level of integration and in reducing the cost of micron-scale waveguide circuits is their mm- to cm-scale minimum bending radius. Fortunately, single-mode rib waveguides with a micron-scale silicon core can be locally transformed into multi-mode strip waveguides that have very high lateral index contrast. Here we show how Euler spiral bends realized with these waveguides can have bending radii below 10 {\mu}m and losses below 0.02 dB/90{\deg} for the fundamental mode, paving way for a novel densely integrated platform based on micron-scale waveguides.Comment: 14 pages, 29 Refs., 5 Fig

Low-error and broadband microwave frequency measurement in a silicon chip

Instantaneous frequency measurement (IFM) of microwave signals is a fundamental functionality for applications ranging from electronic warfare to biomedical technology. Photonic techniques, and nonlinear optical interactions in particular, have the potential to broaden the frequency measurement range beyond the limits of electronic IFM systems. The key lies in efficiently harnessing optical mixing in an integrated nonlinear platform, with low losses. In this work, we exploit the low loss of a 35 cm long, thick silicon waveguide, to efficiently harness Kerr nonlinearity, and demonstrate the first on-chip four-wave mixing (FWM) based IFM system. We achieve a large 40 GHz measurement bandwidth and record-low measurement error. Finally, we discuss the future prospect of integrating the whole IFM system on a silicon chip to enable the first reconfigurable, broadband IFM receiver with low-latency.Comment: 13 pages, 7 figure

Geological Reconnaissance along the Alaska Highway from Fort Nelson, British Columbia, to Watson Lake, Yukon:

by M. Y. Williams.Paper (Geological Survey of Canada) ; 44-28

Low-loss operation of silicon-on-insulator integrated components at 2.6–2.7 µm

Development of mid-infrared photonics is gaining attention, driven by a multitude of sensing applications requiring increasingly compact and cost-effective photonics systems. To this end, low-loss operation of µm-scale silicon-on-insulator photonic integration elements is demonstrated for the 2.6–2.7 µm wavelength region. The platform utilizes the 3 µm thick silicon core layer technology enabling demonstration of low-loss and low birefringence waveguides. Measurements of record low single mode waveguide propagation losses of 0.56 ± 0.09 dB/cm and bend losses <0.08 dB for various miniaturized bend geometries are presented and validated by simulation. Furthermore, a wavelength filter based on echelle grating that allows to select several operating channels within the 2.64–2.7 µm band, with a linewidth of ∼1.56 nm for each channel is presented.Peer reviewe

Data transmission at 1.3 µm using hybrid integrated silicon interposer and GalnNAs/GaAs electroabsorption modulator

Transmission of NRZ data at 12.5 Gbit/s is demonstrated using a hybrid integrated silicon photonics optical interconnect. The interconnect comprises a dilute nitride quantum well electroabsorption modulator on GaAs substrate, which is optically coupled to large core Si waveguide

Data transmission at 1300 nm using optical interposer comprising hybrid integrated silicon waveguide and dilute nitride electroabsorption modulator

High speed back-to-back transmission of NRZ data at 12.5 Gbit/s was achieved over a repeaterless optical network without the use of forward error correction or optical clock recovery using a hybrid integrated silicon photonics optical interconnect. The interconnect comprises an electroabsorption modulator based on dilute nitride multiple quantum well material on GaAs substrate optically coupled to large core silicon waveguide using passive alignment and flip-chip bonding

Sää- ja ilmastoriskien hallinta ja tietolähteet Suomessa

Raportissa kuvaillaan sää- ja ilmastoriskien hallintaa ja siihen liittyvien tietolähteiden käyttöä Suomessa. Raportti perustuu kolmeen erilliseen, mutta toisiaan tukevaan työvaiheeseen. Ensimmäinen työvaihe koostui kahdesta verkkokyselystä, joista toinen oli suunnattu kunnille ja toinen suomalaisille organisaatioille yleisesti. Kyselyillä kartoitettiin vastaajien kokemuksia sää- ja ilmastoriskeistä, niiden hallintaa ja käytettyjä tietolähteitä. Toisen työvaiheen muodosti sidosryhmätyöpaja, jonka tavoitteena oli vahvistaa kyselyn pääpiirteiset tulokset ja kerätä ajatuksia sää- ja ilmastoriskien hallinnan ja sitä tukevien palveluiden kehittämiseen. Kolmas työvaihe koostui kirjallisuusperustaisesta toimialakartoituksesta, jossa koottiin yhteen tietoa sää- ja ilmastoriskeistä ja niiden hallinnasta valituilla yhteiskunnan aloilla (vesivarat, vesihuolto, energia, maatalous, liikenne, matkailu, kuntasektori ja finanssiala). Kukin kolmesta työvaiheesta tuloksineen on esitelty raportissa erikseen. Tulokset viittaavat siihen, että vaikka säällä ja ilmastolla on merkittäviä vaikutuksia yhteiskunnan eri aloille ja toimijoille, on niiden aiheuttamien riskien hallinta vaihtelevaa. Yhteistyö eri muodoissaan koetaan tärkeäksi parannettaessa kykyä sää- ja ilmastoriskien hallintaan. Raportti perustuu ELASTINEN-hankkeessa tehtyyn työhön. Tämä julkaisu on toteutettu osana valtioneuvoston vuoden 2015 selvitys- ja tutkimussuunnitelman toimeenpanoa