Tunable optical dual-comb experiments using silicon Mach- Zehnder modulators

International audienceDual comb spectroscopy is a technique that simultaneously enables high signal-to-noise ratio and quasi-instantaneous measurements of optical spectra. It requires the generation of two mutually coherent optical frequency combs, and electro-optical modulation of a monochromatic carrier can be used for this purpose. By tuning the applied modulation frequency, it is possible to control the spacing between the lines of the electro-optical frequency combs (EOFCs), and by changing the input carrier frequency, it is possible to control the EOFCs absolute frequencies. On-chip EOFC generators are highly desirable to develop low-cost and low-weight dual-comb systems. In this context, silicon photonics is a promising technology, as it benefits from CMOS compatible fabrication process. In this work, a demonstration of dual-comb generation is performed, using two silicon Mach-Zehnder modulators. The tunablity of the obtained 5 main beat notes was studied for an input wavelength ranging from 1530 nm to 1570 nm, and for a driving modulation frequency between 1 GHz and 12 GHz