Ph.D. candidate in Ingegneria Elettrica, Elettronica E Delle Comunicazioni , 41st cycle (2025-2028)
Department of Electronics and Telecommunications (DET)
External Collaborator
Department of Electronics and Telecommunications (DET)
Profile
PhD
Research topic
Physics-based modeling and design of high-speed VCSELs for datacom: RIN noise characterization, polarization control, and external optical feedback.
Tutors
- Mariangela Gioannini
- Pierluigi Debernardi
Keywords
Biography
He received his Master's degree in Electronics Engineering from Politecnico di Torino in 2025 with a final grade of 110/110 cum laude, with a specialization in Radio Frequency Systems Design. He previously obtained his Bachelor's degree in Information Engineering (Electronics track) from the Università degli Studi dell'Aquila in 2023, with a final grade of 110/110. Prior to starting his PhD, he completed a six-month internship at Coherent Corp. in Zurich, where he characterized VCSEL chips through RIN, optical spectra, small-signal modulation response, eye diagram, and S-parameter measurements, developed Python-based data analysis pipelines, and contributed to the design of three next-generation VCSEL prototypes.
Research activities and objectives
The research is framed within the context of very high-speed optical communications, where VCSELs represent the reference laser source for optical interconnects in data centers. As transmission speeds scale toward and beyond 200 Gb/s per lane, modulation and noise specifications become increasingly demanding, rendering established device models and architectures developed at lower speeds inadequate. The research benefits from the infrastructure and expertise of VCSELence, a collaborative research agreement between the Photonext Interdepartmental Center of Politecnico di Torino, IEIIT-CNR, and Fondazione LINKS, dedicated to the development of next-generation VCSEL technologies.
The PhD project is structured around three main research axes.
The first concerns the application and validation of dynamic models coupling the optical field in VCSELs and the carrier distribution within the cavity, already developed at Politecnico di Torino, applied to the interpretation of experimental results obtained by Coherent on fabricated devices. This includes large-signal and small-signal modulation response simulation, RIN noise characterization, and cross-validation against experimental measurements such as LIV curves, S-parameters, eye diagrams, and optical spectral analysis.
The second axis addresses the extension and upgrade of existing models to incorporate physical phenomena relevant to Coherent devices that current formulations do not adequately capture: realistic optical mode profiles, non-uniform current injection, polarization dynamics, and the effect of external optical feedback on laser noise. These aspects are of particular relevance in real transceiver architectures.
The third axis is directed toward the design of novel VCSEL devices with improved modulation speed and noise tolerance, with the objective of providing Coherent with simulation-derived design guidelines and contributing to the fabrication and testing of optimized devices. In parallel, the project includes the development of novel measurement techniques specifically conceived to characterize aspects of Coherent devices not adequately covered by standard methodologies, with the aim of extracting otherwise inaccessible physical information.
The methodological approach integrates advanced numerical simulation in MATLAB, high-frequency experimental measurement techniques up to 40 GHz, and automated data analysis. The close collaboration with Coherent Corp. ensures that developed models are continuously benchmarked against experimental results on real devices, guaranteeing direct industrial relevance to all research outputs.