Mid-infrared Integrated Electro-optic Modulator Operating up to 225 MHz between 6.4 and 10.7 μm Wavelength

Mid-infrared spectroscopy is essential for identifying molecular species, while related electro-optic modulators are crucial for signal-to-noise enhancement via synchronous detection. Therefore, the development of integrated modulators is expected to have a major impact in compact and widespread sensing applications. In this work, we experimentally demonstrate a broadband integrated electro-optic modulator, based on a graded-index SiGe photonics platform and free-carrier plasma dispersion effect. Optical modulation is reported from 6.4 to 10.7 mu m wavelength, showing an operational frequency up to 225 MHz. These results pave the way for the development of multimolecule on-chip spectroscopic systems, operating at the longest mid-infrared wavelengths.

Automated summary

Mid-infrared spectroscopy is crucial for identifying molecular species, and integrated modulators are expected to have a significant impact in sensing applications. This work demonstrates a broadband integrated electro-optic modulator, paving the way for the development of multi-molecular on-chip spectroscopic systems operating at the longest mid-infrared wavelengths.