9 November 2017 11:30Ge-rich SiGe photonic integrated circuits for mid-IR spectroscopy

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Event Details

Delphine Marris-Morini
awardee of the ERC starting grant INsPIRE
Université Paris-Sud – C2N Laboratory for Photonics and Nanostructures

Mid-infrared (mid-IR) spectroscopy is a nearly universal way to identify chemical and biological substances, as most of the molecules have their vibrational and rotational resonances in the mid-IR wavelength range. Commercially available mid-IR systems are based on bulky and expensive equipment, while lots of efforts are now devoted to the reduction of their size down to chip-scale dimensions. The demonstration of mid-IR photonic circuits on silicon chips will benefit from reliable and high-volume fabrication to offer high performance, low cost, compact, low weight and power consumption photonic circuits, which is particularly interesting for mid-IR spectroscopic sensing systems that need to be portable and low cost.

Among the different materials available in silicon photonics, Germanium (Ge) and Silicon-Germanium (SiGe) alloys with a high Ge concentration are particularly interesting because of the wide transparency window of Ge up to 15 µm. In that regard, we have demonstrated that graded-index SiGe alloys can be an ideal material choice since they permit good control of the optical properties by fine tuning the Ge concentration along the growth direction. By doing that, we have recently shown broadband low-loss waveguides and ultra-wideband integrated Mach Zehnder interferometer from 5.5 µm to 8.5 µm wavelength. To complete the functionalities of such mid-IR integrated platform, we are now exploring the possibility to use these SiGe platforms for the development of active nonlinear mid-IR devices owing to the large nonlinear Kerr index (n2) of Ge and the absence of two-photon absorption (TPA) beyond λ = 3.1 µm.

This project is developed in the framework of an ERC starting grant (INsPIRE) in collaboration between Paris Sud University and L-Ness Politecnico Di Milano

Time

9 November 2017
11:30

Location

Politecnico di Milano, Aula Rossa - Dipartimento di Fisica

P.zza Leonardo da Vinci 32 20133 Milano

Organizer

Politecnico di Milano

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