New photonic architectures for mid-infrared gas sensors integrated on silicon [article]

Ainur Koshkinbayeva
2017 arXiv   pre-print
This work focuses on optical multiplexers for mid-IR broadband source in gas sensing application. The design of multiplexer configurations based on two types of diffraction gratings is discussed. Owing to utility of Gaussian approximation of the field and Fourier Optics, we developed a semi-analytical tool allowing to evaluate the responses of array waveguide grating (AWG) and planar concave grating (PCG). This approach also opened the way to implement numerical phase error analysis by
more » ... ng normal distribution of errors and to study the correlation between standard deviation of phase errors and the level of crosstalk. FTIR spectroscopy measurement results of 5.65 micrometer AWGs, built with SiGe graded index core encapsulated in a thick Si cladding on standard silicon substrate, are compared with the theoretical expectations. We have also performed evaluation of AWG response at elevated temperatures, in the range between 20oC and 41oC. The spectral shift showed linear dependence with the temperature, which is in a good agreement with simulation predictions.
arXiv:1709.08922v1 fatcat:suhgp4344nh47neut6n6ktigku