Dispositifs de contrôle de la polarisation en photonique sur silicium

Controlling light polarization is a fundamental requirement in integrated photonics, as many optical systems rely on the ability to manipulate and separate polarization states. Silicon-on-insulator (SOI) technology is one of the most promising platforms for integrated optics due to its high refractive index contrast, which enables high-density integration of optical components, and its compatibility with CMOS fabrication processes. However, silicon absorption becomes high at wavelengths below 1200 nm, limiting its use for example in quantum applications that often exploit wavelengths shorter than the typical telecommunication ones (1300 nm, 1550 nm). This limitation has motivated the adoption of silicon nitride (SiN), which allows operation at shorter wavelengths while potentially offering lower propagation losses compared to silicon and being compatible with large-scale fabrication processes. Despite these advantages, polarization control in SiN photonics, particularly below 1200 nm, has received relatively little attention. This thesis addresses this gap by developing compact and high-performance polarization-control devices based on the SiN platform operating at sub-telecom and telecom wavelengths. Several components were designed, fabricated, and experimentally validated, including polarization beam splitters, polarization splitter-rotators, and polarization rotators. Different design strategies were investigated to enhance device compactness and robustness, including subwavelength waveguides and tapered geometries. These approaches demonstrate that SiN platform can effectively support advanced polarization management devices, despite its lower refractive index contrast compared to SOI platform. Overall, this work establishes a comprehensive foundation for polarization control on the SiN platform, demonstrating its potential for broadband, low-loss, and compact integration. The results pave the way toward the realization of complex, fully integrated photonic circuits capable of active and passive polarization management for applications ranging from telecommunications to quantum information processing.