Recent advances in the development of SWIFTS for broadband millimeter spectroscopy

We present latest developments of the millimetric Stationary Waves Integrated Fourier Transform Spectrometer (SWIFTS) that uses the Kinetic Inductance Detectors (KID) technology. SWIFTs are on-chip autocorrelator spectrometers where the incoming signal forms an interferogram by reflection in a short-circuited coplanar wave-guide. By collecting electromagnetic (EM) energy along the guide, one can retrieve this interference pattern. A subsequent offline Fourier transform gives spectral information with a moderate resolution (~500-1000). SWIFTS concept has already been proven to work in the optical and microwave (<20 GHz) bands. It will be useful in any application where integrated and broadband spectral analysis is needed, as an example it will be a practical alternative to Martin-Pupplet interferometer. In practice, fabrication of such a device is very challenging mostly because the set of detectors has to collect energy without destroying the interference pattern. As a consequence, design of the coupling parts is a crucial problem that has to be tackled with the help of EM simulation tools. We present here the SWIFTS principle of operation, details of fabrication, and the latest simulations results.