Integrated broadband dual-polarization Ge-rich SiGe mid-infrared Fourier-transform spectrometer

Qiankun Liu (1) , Joan Manel Ramírez (1) , Vladyslav Vakarin (1) , Xavier Le Roux (1) , Carlos Alonso-Ramos (1) , Enrico Talamas Simola , Jacopo Frigerio (2) , Andrea Ballabio (2) , Enrico Talamas Simola (2) , David Bouville (1) , Laurent Vivien (1) , Giovanni Isella (2) , Delphine Marris-Morini (1)

1 C2N - Centre de Nanosciences et de Nanotechnologies [Orsay]
2 Politecn Milan, LNESS Dipartimento Fis, I-22100 Como, Italy

Miniaturized on-chip spectrometers covering a wide band of the mid-infrared spectrum have an immense potential for multi-target detection in high-impact applications like chemical sensing or environmental monitoring. Specifically, multi-aperture spatial heterodyne Fourier transform spectrometers (SHFTS) provide high throughput and improved tolerances against fabrication errors, compared to conventional counterparts. Still, state-of-the-art implementations have only shown single polarization operation in narrow bandwidths within the near and short infrared. Here, we demonstrate the first dual-polarization ultra wideband SHFTS working beyond 5 µm wavelength. We exploit the unique flexibility in material engineering of the graded-index germanium-rich silicon-germanium (Ge-rich SiGe) photonic platform to implement a SHFTS that can be operated in an unprecedented range of 800 cm-1, showing experimental resolution better than 15 cm-1 for both orthogonal polarizations and free-spectral-range of 132 cm-1, in the range between 5 µm and 8.5 µm wavelength

Domaines: Optique / photonique

Qiankun Liu, Joan Manel Ramírez, Vladyslav Vakarin, Xavier Le Roux, Carlos Alonso-Ramos, et al.. Integrated broadband dual-polarization Ge-rich SiGe mid-infrared Fourier-transform spectrometer. Optics Letters, 2018, 43 (20), ⟨10.1364/OL.43.005021⟩. ⟨hal-01891844⟩