Dipartimento di Elettronica e Informazione

Politecnico di Milano

20133 Milano (Italy)

Piazza Leonardo Da Vinci 32

Prof. Franco Zappa

Phone     (+39) 02-2399.6149

Fax         (+39) 02-2367604

E-mail     zappa@elet.polimi.it


Single Photon Avalanche Diodes

            Active Quenching Circuits

                        Single Photon Counting Modules



Publications on SPAD and related matters



Prof. Sergio Cova               (+39) 02 2399.6103           cova@elet.polimi.it
Prof. Massimo Ghioni          (+39) 02 2399.6093           ghioni@elet.polimi.it
Prof. Franco Zappa             (+39) 02 2399.6149           zappa@elet.polimi.it
Dr. Ivan Rech                     (+39) 02 2399.3700           rech@elet.polimi.it
Dr. Alberto Tosi                  (+39) 02 2399.6174           tosi@elet.polimi.it


Dr. Andrea Giudice             (+39) 0471 051212            agiudice@microgate.it

Dr. Simone Tisa                 
Dr. Angelo Gulinatti            
Dr. Alessandro Restelli       
Ing. Ivan Labanca              



Via Stradivari 4, 39100 Bolzano (Italy)





Research Topic:

Microelectronic and optoelectronic devices and circuits for high-speed, high-sensitivity optical measurements




Single Photon Avalanche Diodes, Photon Counting, Time Correlated Photon Counting, Active Quenching Circuits




Study and development of microelectronic devices and circuits for detecting, processing and measuring optical signals with high-sensitivity and accuracy. Emphasis on single-photon-counting SPC and time-correlated photon-counting TCPC, with continued work on Single-Photon Avalanche Diodes SPADs and associated Active-Quenching Circuits. Single and array detectors are investigated and developed for scientific and industrial applications, ranging from advanced microanalytical techniques for medical diagnostic applications (DNA and proteyn analysis) to high-resolution high-sensitivity optical ranging (OTDR in optical fibers, satellite ranging, object profiling in mechanical and aerospace applications) to ULSI circuit characterization exploiting infrared photon emission from MOSFETs.






Main Projects:

“Development of a single-photon spectrometer/microscope: probing the conformational dynamics of single biomolecules on a photon by photon basis”, in collaboration with the Department of Chemistry and Chemical Biology, Harvard University, Grant DBI-0138028.

“Photon Counter Arrays for Adaptive Optics”, in collaboration with ESO, European Southern Observatory, Garching (Germany).

“Time-resolved luminescence measurements and simulations in ULSI chips”, in collaboration with IBM, T.J. Watson Research Center, Yorktown Heights (USA).


European Community funded projects:

”SECOQ: development of a global network for Secure Communication based on Quantum Cryptography”, VI European Framework Project, IST.

”EQUIS: Enabling Technologies for Quantum Information Systems” V European Framework Project, IST-1999-11594

”MICROSPAD: Microelectronic single-photon detectors and instrumentation for high-sensitivity analytical techniques”, IV European Framework Project, IST.


National projects:

”Micro-systems for genetic diagnostics”, FIRB 2002, Italian Ministry for Education and Research.

"Electro-Luminescence Microscope: Optoelectronic apparatus for non-invasive testing of ULSI circuits at 30GHz", Cofin 2003, Italian Ministry for Education and Research.

"Development of monolithic photon counting arrays for adaptive optic systems and high-energy transient analysis in astrophysics", Cofin 2002, Italian Ministry for Education and Research.




IBM- T.J. Watson Research Center

European Southern Observatory (ESO)


Carl Zeiss



Harvard University

Heriot Watt University



Silicon SPADs and Arrays

SPAD mounted on thermoelectric Peltier cooler


Variable PinHole Photodetector for Confocal Microscopes


SPAD Arrays for Fast Transient Imaging and Adaptive Optics


Integrated Active Quenching Circuits


Fully monolithic photon counting chip

Hybrid Active Quenching Circuits


Plug&Play Photon Counting Modules

Complete set-ups for DNA analysis


Optic non-invasive testing of VLSI chips




Publications on SPAD and related matters








“Active quenching circuit for avalanche photodiodes”,

U.S. Patent No. 4,963,727, Date 16 October 1990,

Italian Patent 22367 A/88 filed October 20, 1988



S.Cova, A.Lacaita, M.Ghioni

"Fotodiodo con soppressione degli effetti legati alla raccolta per diffusione di portatori di carica fotogenerati", Italian Patent MI92A 002310 filed October 7, 1992



S.Cova, M.Ghioni, F.Zappa

“Circuit for high precision detection of the time of arrival of photons falling on single photon avalanche diodes"

US patent No. 6,384,663 B2, date May 7, 2002 (priority date March 9, 2000)

European patent application n. 01200851.2-2217, filed March 6, 2001,

Italian Patent MI2000 A 000467, filed March 9, 2000



F.Zappa, S.Cova, M.Ghioni

“Monolithic circuit of active quenching and active reset for avalanche photodiodes ”

US patent 6,541,752 B2, date April 1,2003 (priority date March 9, 2000)

European patent application n. 01200852.2-2217, filed March 6, 2001,

Italian Patent MI2000 A 000466, filed March 9, 2000



S.Cova, F.Zappa, M.Ghioni, R.Grub, E.Derndinger, T.Hartmann

“High sensitivity photodetector device with integrated micrometric diaphragm for confocal microscopes”,

US patent application n. 10/257,071 filed Oct. 9, 2002

European patent application n. 01927893.6 filed Oct. 31, 2002

International application number  PCT/EP 01/04008, filed April 9, 2001

Italian Patent MI2000 A 000765, filed April 10, 2000