Silicon and InGaAs/InP SPADs for near-infrared applications

Alberto Tosi
March 18th, 2021 ALBERTO TOSI

L4H SEMINAR: Silicon and InGaAs/InP SPADs for near-infrared applications
Light Seminar Series, March 18, 2021, 12:00-13:00. Online (Zoom)


Ultimate sensitivity in measurements of optical signals with picosecond resolution can be achieved with Single-Photon Avalanche Diodes (SPADs). Such detectors produce a current pulse that marks the arrival time of the photon with picosecond precision. Nowadays, silicon SPADs and InGaAs/InP SPADs are well developed and are employed in a growing number of applications, from biology to medical diagnosis, from quantum technologies to LIDAR.

Silicon SPADs are available both as single pixel and array. In detail, CMOS SPAD arrays based on smart pixels (that include counting and timing circuitry) are the basis for single-photon counting cameras with very high frame rate and single-photon sensitivity. Such cameras can be used for applications like biomedical applications, microscopy and 3D acquisitions (LIDAR and non-line-of-sight imaging).

InGaAs/InP SPADs are the best choice for practical and reliable systems with high detection performance in the near-infrared wavelength range (1 µm - 1.7 µm). Planar InGaAs/InP SPADs with good performance in terms of photon detection efficiency, dark-count rate and timing jitter are the detectors of choice for many applications, like quantum cryptography, LIDAR, and also for emerging ones, also in the biomedical field.

Short bio:

Alberto Tosi

Associate Professor at Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria (DEIB)

He received his Master’s degree in electronics engineering and his PhD degree in information technology engineering from Politecnico di Milano in 2001 and 2005, respectively. He was Assistant Professor from 2006 to 2014 and has been an Associate Professor of Electronics since 2014, both at Politecnico di Milano. In 2004, he was a Student with the IBM T. J. Watson Research Center, Yorktown Heights, NY, working on optical testing of CMOS circuits.

He designs, develops and exploits silicon, InGaAs/InP and Ge-on-Si Single-Photon Avalanche Diodes (SPADs). He works on arrays of SPADs for 2D and 3D applications, on silicon photomultipliers and on time-correlated single-photon counting electronics. He develops single-photon counting modules and time-to-digital converters for high-resolution high-throughput applications. In collaboration with other research groups, he develops new applications of single-photon counting in various fields, from biomedicine to secure communications, from material science to LIDAR.

He has been the principal investigator for POLIMI – DEIB in four EC funded projects, one DARPA funded project and one ESA funded project. He is co-founder of the start-up company pioNIRS s.r.l. ( He is co-author of more than 240 papers on peer-reviewed journals and conference proceedings, and he is the co-inventor of 3 patents and 2 patent applications. His H-index is 39 (according to Scopus, author ID 35499994500).


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