45 research outputs found
Vilhelm Lundstedt’s ‘Legal Machinery’ and the Demise of Juristic Practice
This article aims to contribute to the academic debate on the general crisis faced by law schools and the legal professions by discussing why juristic practice is a matter of experience rather than knowledge. Through a critical contextualisation of Vilhelm Lundstedt’s thought under processes of globalisation and transnationalism, it is argued that the demise of the jurist’s function is related to law’s scientification as brought about by the metaphysical construction of reality. The suggested roadmap will in turn reveal that the current voiding of juristic practice and its teaching is part of the crisis regarding what makes us human
Late Cenozoic history of deep water circulation in the western North Pacific: Evidence from Nd isotopes of ferromanganese crusts
Integration of mid-infrared SOI photonics with microfluidics
This work describes the integration of mid-infrared (MIR) silicon photonics with PDMS microfluidics to perform absorption spectroscopy of IPA-water solutions. The MIR spectral region contains strong absorption bands for many molecules, and photonic devices operating in the MIR can be used in many sensing applications. In this work a preliminary demonstration of a silicon-on-insulator (SOI) device is carried out in which the transmission spectra of different concentrations of water-IPA solutions are measured at wavelengths between 3.725 μm and 3.888 μm. A PDMS microfluidic channel is integrated with the waveguides in order to improve the repeatability of sample handing, reduce reagent volumes and prevent evaporation of the analyte. A microfluidic channel with 3000 x 100 μm cross-section and 30 mm length is bonded to a SOI chip comprising 500 nm thick rib waveguides and a 2 μm thick SiO2 top cladding isolating the waveguide mode from the analyte. Trenches were patterned into the SiO2 cladding to create sensing windows of varying lengths (10 μm to 3mm) along different waveguides. The devices were used to detect an expected IPA absorption peak at 3.77 μm, and concentration as low as 3% IPA in water (by volume) was detected. Further work will focus on increasing the sensitivity of the measurement by using increased interaction lengths, reduction of noise and instability, and on the detection of drugs using transmission measurements over a broader wavelength range. </p
Experimental demonstration of an apodized-imaging chip-fiber grating coupler for Si<sub>3</sub>N<sub>4</sub> waveguides
A silicon nitride waveguide is a promising platform for integrated photonics, particularly due to its low propagation loss compared to other complementary metal–oxide–semiconductor compatible waveguides, including silicon-on-insulator. Input/output coupling in such thin optical waveguides is a key issue for practical implementations. Fiber-to-chip grating couplers in silicon nitride usually exhibit low coupling efficiency because the moderate index contrast leads to weak radiation strengths and poor directionality. Here, we present the first, to the best of our knowledge, experimental demonstration of a recently proposed apodized-imaging fiber-to-chip grating coupler in silicon nitride that images an in-plane waveguide mode to an optical fiber placed at a specific distance above the chip. By employing amplitude and phase apodization, the diffracted optical field of the grating is matched to the fiber mode. High grating directionality is achieved by using staircase grating teeth, which produce a blazing effect. Experimental results demonstrate an apodized-imaging grating coupler with a record coupling efficiency of -1.5 dB and a 3 dB bandwidth of 60 nm in the C-band
Chemical Characterization of Cobalt Crust from Afanasy-Nikitin Seamount in the Eastern Indian Ocean by Inductively Coupled Plasma Time-of-Flight Mass Spectrometry
Compositional variation and genesis of ferromanganese crusts of the Afanasiy—Nikitin Seamount, Equatorial Indian Ocean
High-speed silicon Michelson interferometer modulator and streamlined IMDD PAM-4 transmission of Mach-Zehnder modulators for the 2 μm wavelength band
We demonstrate high-speed silicon modulators optimized for operating at the wavelength of 2 μm. The Mach-Zehnder interferometer (MZI) carrier-depletion modulator with 2 mm phase shifter has a single-arm modulation efficiency (Vπ ·Lπ) of 2.89 V·cm at 4 V reverse bias. Using a push-pull configuration it operates at a data rate of 25 Gbit/s OOK with an extinction ratio of 6.25 dB. We also proposed a mathematically-analysed streamlined IMDD PAM-4 scheme and successfully demonstrated a 25 Gbit/s datarate PAM-4 with the same 2 mm modulator. A Michelson interferometer carrier-depletion modulator with 0.5 mm phase shift length has also been shown with modulation efficiency (Vπ ·Lπ) of 1.36 V·cm at 4 V reverse bias and data rate of 20 Gbit/s OOK. The Michelson interferometer modulator performs similarly to a Mach-Zehnder modulator with twice the phase shifter length
Low-Temperature NH3-Free Silicon Nitride Platforms for Integrated Photonics
We demonstrate 3 platforms based on silicon nitride layers processed at 350°C and tailored to have different refractive indices. With these platforms, we have successfully fabricated low loss waveguides at telecom wavelengths, temperature tolerant (de)multiplexing devices, nonlinear waveguides, photonic crystal cavities and waveguides