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The ALTIUS Mission (Atmospheric Limb Tracker for Investigation of the Upcoming Stratosphere) aims at the development of a limb sounder based on a small satellite concept (i.e. PROBA-Next small platform). ALTIUS will monitor the distribution and evolution of stratospheric ozone at high vertical resolution in support of operational services and long term trend monitoring. It will provide detailed stratospheric profile information at high vertical resolution, which is a valuable addition to ozone total column for data assimilation systems based on nadir sounders used by operational centers. In addition, some secondary scientific mission objectives are targeted, including measurements of vertical concentration profiles of other atmospheric species. The ALTIUS Mission was first proposed by the Belgian Institute for Space Aeronomy and, after several studies in different programmes within ESA, is now being developed as an element of ESA’s Earth Watch Programme currently with the participation of Belgium, Canada, Luxembourg and Romania. The ALTIUS Mission concept consists of three spectral imagers flying at an altitude of approximately 700 km Sun- Synchronous Orbit on-board the next generation of PROBA platform. The ALTIUS Instrument shall allow observation of the Earth’s atmospheric bright limb in an extended spectral region from the Ultraviolet to the Short Wave Infrared (SWIR). In addition, the ALTIUS instrument shall perform solar and stellar occultation observations in the dark limb. The ALTIUS Instrument three hyperspectral channels are based respectively on Acousto-Optic Tuneable Filters (AOTFs) in the Visible (440-800nm) and SWIR (900-1800nm) range, and a cascade of Fabry Perot Interferometers (FPI) in the UV (250-370nm). The use of tuneable active spectral filter shall allow the ALTIUS Instrument to perform observations with a spectral resolution ranging between 1nm and 10nm in an extremely versatile operational concept. The use of the AOTFs and Fabry Perot technologies constitutes a novelty in the limb sounding missions and its development critical aspects as well as its performances have been proven in the frame of an extensive Instrument predevelopment phase. In this phase the critical technologies necessary to ensure the performance and functionalities of the ALTIUS Instrument have been designed, developed and qualified. In particular the following pre-developments were undertaken to pave the way towards Instrument Preliminary Design Review: Design, manufacturing and qualification of the VIS AOTF Assembly and RF control electronics; Design, manufacturing and qualification of the UV FPI assembly stack and control electronics; Development and qualification of UV filters and coatings. Design and manufacturing of sensor electronics based on selected CMOS sensor for UV and VIS channels; Design, manufacturing and partial qualification of the Instrument mechanism; Bread-boarding of the full VIS channel for functionality and end-to-end performances verification. This paper presents the status and main results of the above-mentioned ALTIUS Instrument pre-development activities. In particular: major outcomes during the development process, achieved performances and lessons learned for the continuation of the ALTIUS Instrument flight model design are being highlighted.

We have fabricated a micro-supercapacitor with porous silicon electrodes coated with TiN by atomic layer deposition technique. The coating provides an efficient surface passivation and high electrical conductivity of the electrodes, resulting in stable and almost ideal electrochemical double layer capacitor behavior with characteristics comparable to the best carbon based micro-supercapacitors. Stability of the supercapacitor is verified by performing 50 000 voltammetry cycles with high capacitance retention obtained. Silicon microfabrication techniques facilitate integration of both supercapacitor electrodes inside the silicon substrate and, in this work, such in-chip supercapacitor is demonstrated. This approach allows realization of very high capacitance per foot print area. The in-chip micro-supercapacitor can be integrated with energy harvesting elements and can be used in wearable and implantable microdevices.

Cost effective multi-wavelength light sources are key enablers for wide-scale penetration of gas sensors at Mid-IR wavelength range. Utilizing novel Mid-IR Si-based photonic integrated circuits (PICs) filter and wide-band Mid-IR Super Luminescent Light Emitting Diodes (SLEDs), we show the concept of a light source that covers 2.5...3.5 μm wavelength range with a resolution of

Athena is a space-based X-ray observatory intended for exploration of the hot and energetic universe. One of the science instruments on Athena will be the X-ray Integrated Field Unit (X-IFU), which is a cryogenic X-ray spectrometer, based on a large cryogenic imaging array of Transition Edge Sensors (TES) based microcalorimeters operating at a temperature of 100mK. The imaging array consists of 3800 pixels providing 2.5 eV spectral resolution, and covers a field of view with a diameter of of 5 arc minutes. Multiplexed readout of the cryogenic microcalorimeter array is essential to comply with the cooling power and complexity constraints on a space craft. Frequency domain multiplexing has been under development for the readout of TES-based detectors for this purpose, not only for the X-IFU detector arrays but also for TES-based bolometer arrays for the Safari instrument of the Japanese SPICA observatory. This paper discusses the design considerations which are applicable to optimise the multiplex factor within the boundary conditions as set by the space craft. More specifically, the interplay between the science requirements such as pixel dynamic range, pixel speed, and cross talk, and the space craft requirements such as the power dissipation budget, available bandwidth, and electromagnetic compatibility will be discussed.

This paper explains and demonstrates the unique properties of micron-size silicon-on-insulator (SOI) waveguides. It gives an overview of the silicon photonics research at VTT, as well as latest R&D highlights. The benefits of high mode confinement in rib and strip waveguides are described, reaching from low losses and small footprint to polarization independent operation and ultra-wide wavelength range from 1.2 to over 4 μm. Most of the results are from photonic integrated circuits (PICs) on 3 μm SOI, while a 25 Gbps link with a transceiver on 12 μm SOI is also reported. Wavelength multiplexing and filtering is demonstrated with some breakthrough performance in both echelle gratings and arrayed waveguide gratings. Lowest losses are below 1 dB and lowest cross-talk is below -35 dB. Progress towards monolithically integrated, broadband isolators is described, involving polarization splitters, reciprocal polarization rotators and nonreciprocal Faraday rotation in 3 μm SOI waveguide spirals. Quick update is presented about switches, modulators and Ge photodiodes up to 15 GHz bandwidth. Hybrid integration of lasers, modulators and photodiodes is also reported. The added value of trimmed SOI wafers and cavity-SOI wafers in Si photonics processing is addressed. Latest results also include up-reflecting mirrors with