Maillefer (Switzerland)

We show how spatiotemporal quasi-phase-matching emerges from all-optical poling of silicon nitride microresonators. Enabled by the coherent photogalvanic effect, the photoinduced χ(2) grating oscillates in space and time, yielding quasi-phase-matched and Doppler-shifted second-harmonic generation.

Quantum interconnects will be key to scale quantum computers and deploy quantum networks. I discuss what is required to realize practical, high-bandwidth quantum interconnects using microwave-to-optical transducers based on integrated photonics. Full-text article not available; see video presentation

Abstract Nonlinear continuum finite element (CFE) analyses rely on accurate multiaxial constitutive law formulations along with reliable imperfection patterns for simulating nonlinear geometric instabilities in steel members under mechanical loading. Validations of these models usually rely on conventional measurements of macroscopic parameters (e.g., displacement and strain field). It is common to use global deformation characteristics (e.g., deduced moment versus chord rotation) for model validation purposes of steel members exhibiting inelastic cyclic local buckling. The reason is that measurements from conventional strain gauge readings are not deemed to be reliable well before the onset of local buckling. This is potentially problematic when the accurate prediction of local strain demands is essential. This paper discusses the experimental results from a steel beam instrumented with a digital image correlation (DIC) system and how optical measurements acquired from DIC can be used to benchmark a CFE model representation of this beam. It is shown that while different CFE model types simulate accurately the moment rotation relationship of the steel beam, local strain demand predictions could vary considerably between model types. The results suggest that DIC measurements can inform the selection of proper imperfection patterns to be used in CFE models for the reliable estimation of inelastic strain demands.

Abstract Lithium niobate on insulator (LNOI) has emerged as a promising platform for photonic integrated circuits, with a fast‐growing toolbox of components. This paper proposes, designs, and experimentally demonstrates compact subwavelength grating (SWG) waveguides on an LNOI platform for on‐chip mode and polarization manipulation. To overcome the limitation of waveguide fabrication, the SWGs are designed and formed on a silicon nitride thin film deposited onto the surface of LNOI chip. As proof‐of‐concept devices, the SWG‐based spatial mode filters (including a TE1‐mode‐pass filter and a TE2‐mode‐pass filter) and a TM‐pass polarizer are fabricated successfully on the same chip, with the device lengths of only ≈50 μm. The measured insertion losses for the devices are lower than 3.1 dB, with high extinction ratio larger than 30 dB, at a wavelength of 1550 nm. The proposed and demonstrated SWGs can serve as important building blocks in a series of mode and polarization handling devices for LNOI integrated photonics.

Open-wedge high tibial osteotomy for varus osteoarthritis of the knee is a successful treatment option, but is associated with potential intraoperative complications, jeopardizing outcome. We describe four technical hints avoiding complications as tibia plateau fracture, lateral hinge dislocation, over- and undercorrection, and unwanted increase of the posterior tibial slope and axial malrotation. The technique, which is primarily based on placing five Kirschner-wires (one for the osteotomy direction, two for the external fixator, and two for rotational and slope control) is simple, reproducible, inexpensive, and readily available.

The Entreprises Electriques Fribourgeoises (EEF), a Swiss utility, operate their medium voltage system with isolated neutral. In order to comply with the legal requirements for the security of people, the protection relays trip the lines also in the event of an earth fault. This kind of operation is not appreciated by our customers who have to accept too frequent interruptions of supply, mainly due to faults on the overhead lines. A recent study suggests using a shunt circuit-breaker in the HV/MV substations combined with the existing isolated neutral system. The improvement aimed at is to operate continuously our electrical network in case of an earth fault. Our studies show a potential reduction of supply interruptions of over 50 %. The solution with isolated neutral and a shunt circuit-breaker, consisting in grounding the earth- faulted phase to the ground at the HV/MV substation, seems to have all the advantages of a compensated neutral point (Petersen coil) as well as a lower cost (approx. ratio 1:4).

New UBV photometry for 878 luminous member stars of the Large Magellanic Cloud (LMC) and 13 stars of uncertain membership is presented. The data will be available at Centre de Donnees astronomiques de Strasbourg. Including former observations now UBV data are available for altogether 2470 luminous LMC stars and 2106 foreground stars plus 65 stars of uncertain membership. The observations have been used already for several investigations dealing e.g. with interstellar reddening lines and intrinsic colours, the dust distribution and the calibration of charge-coupled device exposures.

In addition to the list of UBV photometries of 955 galactic foreground stars in the direction to the Large Magellanic Cloud published by Gochermann et al. (1993a), a supplement of 545 stars is presented, which have been measured with the same photometric accuracy. Moreover, less reliable photometries of 379 further fore- ground stars are listed in a separate table. The homo- geneous data base of more than 1 500 high accuracy pho- tometries represented by these stars has been used to con- struct a reddening distribution map of the galactic fore- ground towards the LMC by Oestreicher et al. (1995).