Search

The concept and design of a new type of waveguide device, a multiaperture Fourier-transform planar waveguide spectrometer, implemented as a prototype instrument is presented. The spectrometer's objective is to demonstrate the ability of the new slab waveguide technology for application in remote-sensing instruments. The spectrometer will use a limb-viewing configuration to detect the 1.36μm waveband allowing the concentrations of water vapor in Earth's atmosphere to be measured. The most challenging aspects of the design, assembly, and calibration are presented. Focus will be given to the effects of packaging the spectrometer and interfacing to the detector array. Stress-induced birefringence will affect the performance of the waveguides, therefore, the design of a stress-free mounting over a range of temperatures is important. Spectral retrieval algorithms will have to correct for expected fabrication errors in the waveguides. Data-processing algorithms will also be developed to correct for nonuniformities of input brightness through the array, making use of multimode interference output couplers to capture both the in-phase and anti-phase interferometer outputs. A performance assessment of an existing breadboard spectrometer will demonstrate the capability of the instrument. © 2011 CASI.

We present the development of a compact planar waveguide Fourier-transform spectrometer for high-resolution and high-throughput spectroscopy. The prototype device is designed to monitor the water vapor absorption band near λ= 1364 nm in the atmosphere from an Earth-orbiting satellite. The instrument is fully static (i.e. no moving parts) and it is based on a unique slab waveguide Fourier-transform spectrometer concept implemented with silicon-on-insulator (SOI) technology. The spectrometer input is formed by an array of N independent waveguide apertures, thereby significantly (Nx) increasing light gathering capability (étendue) compared to conventional single-aperture devices. We also discuss a practical implementation of the multi-aperture concept based on an array of surface grating couplers. © 2011 IEEE., 2011 13th International Conference on Transparent Optical Networks, ICTON 2011, 26 June 2011 through 30 June 2011, Stockholm

Neutral Beam Injectors (NBI), which need to be strongly optimized in the perspective of DEMO reactor, request a thorough understanding of the negative ion source used and of the multi-beamlet optics. A relatively compact RF ion source, named NIO1 (Negative Ion Optimization 1), with 9 beam apertures for a total H(-) current of 130 mA, 60 kV acceleration voltage, is being installed at Padua, in Consorzio RFX, to provide a test bench for source optimizations in the framework of the accompanying activities in support to the ITER NBI test facility. NIO1 construction and status of the overall installation, including a high voltage deck and an optical cavity ring down spectrometer are here summarized and reported. Plasma and low voltage beam operations are discussed. Development of a sampling beam calorimeter (with small sampling holes, and a segmented cooling circuit) is also discussed.