Wavelength laser source detection with 20 pm resolution over a 70 nm spectral bandwidth

SWIFTS is an integrated microspectrometer that achieves high spectral resolution by probing an optical waveguide, the ultimate integration for obtaining a long interferogram. However, due to undersampling, the usable repetitive spectral band is limited. However, this spectral band can be doubled while improving spectral resolution by using a specific algorithm associated with a calibration table. Here, an analytical model is detailed to explain this improvement and is validated by experimental results. Thanks to this development, a new design is proposed to widen the spectral band from 7 to 70 nm with a spectral resolution of 20 pm.