The present work is focused on the description of a SPAD-based pixel suitable for random bits extraction. Compared to
the state-of-the-art, the proposed approach aims at improving the performance of the random generator with respect to
possible photon flux variation. Thanks to the adopted methodology, the entropy of the output is maintained almost
constant over a wide range of operating conditions. The principle has been validated through simulations and
implemented in a compact pixel, suitable for array implementation.
The SPADnet FP7 European project is aimed at a new generation of fully digital, scalable and networked photonic components to enable large area image sensors, with primary target gamma-ray and coincidence detection in (Time-of- Flight) Positron Emission Tomography (PET). SPADnet relies on standard CMOS technology, therefore allowing for MRI compatibility. SPADnet innovates in several areas of PET systems, from optical coupling to single-photon sensor architectures, from intelligent ring networks to reconstruction algorithms. It is built around a natively digital, intelligent SPAD (Single-Photon Avalanche Diode)-based sensor device which comprises an array of 8×16 pixels, each composed of 4 mini-SiPMs with in situ time-to-digital conversion, a multi-ring network to filter, carry, and process data produced by the sensors at 2Gbps, and a 130nm CMOS process enabling mass-production of photonic modules that are optically interfaced to scintillator crystals. A few tens of sensor devices are tightly abutted on a single PCB to form a so-called sensor tile, thanks to TSV (Through Silicon Via) connections to their backside (replacing conventional wire bonding). The sensor tile is in turn interfaced to an FPGA-based PCB on its back. The resulting photonic module acts as an autonomous sensing and computing unit, individually detecting gamma photons as well as thermal and Compton events. It determines in real time basic information for each scintillation event, such as exact time of arrival, position and energy, and communicates it to its peers in the field of view. Coincidence detection does therefore occur directly in the ring itself, in a differed and distributed manner to ensure scalability. The selected true coincidence events are then collected by a snooper module, from which they are transferred to an external reconstruction computer using Gigabit Ethernet.
Fusion of multispectral images has been explored for many years for security and used in a number of commercial products. CEA-Leti and FBK have developed an innovative sensor technology that gathers monolithically on a unique focal plane arrays, pixels sensitive to radiation in three spectral ranges that are terahertz (THz), infrared (IR) and visible. This technology benefits of many assets for volume market: compactness, full CMOS compatibility on 200mm wafers, advanced functions of the CMOS read-out integrated circuit (ROIC), and operation at room temperature. The ROIC houses visible APS diodes while IR and THz detections are carried out by microbolometers collectively processed above the CMOS substrate. Standard IR bolometric microbridges (160x160 pixels) are surrounding antenna-coupled bolometers (32X32 pixels) built on a resonant cavity customized to THz sensing. This paper presents the different technological challenges achieved in this development and first electrical and sensitivity experimental tests.
In this work, a compact low-cost system designed to detect low amounts of proteins in biological fluids is presented. The
system, based on time-gated fluorescence detection principle, is composed by a Single-Photon Avalanche Diode (SPAD)
pixel array, a LED excitation light source and a micro-machined reaction chamber coupled to a microfluidic network. A
dual-site binding strategy based on DNA aptamers is used for target protein recognition. The microreactor, composed of
an array of microwells covered with a transparent membrane, is functionalized with a primary aptamer, while a
fluorescent-tagged secondary aptamer is used for the detection. Preliminary measurements demonstrate the feasibility of
fluorescence lifetime detection to discriminate between different fluorophores. The detection of human thrombin protein
in 300nM concentration is reported as a biological proof of principle of the biosensor.
In this paper a Time-Of-Flight range camera based on Current Assisted Photonic Demodulators is presented. The sensor,
fabricated in a 0.18 μm CMOS technology, features 120x160 pixel resolution with 10μm pixel pitch and 24% fill factor.
Pixel, camera and system architectures are described highlighting the most important design issues, and a selection of
experimental results is presented. The chip has a power consumption of 200mW, mainly due to the contribution of
modulation current. A range camera system was realized using the proposed sensor, a focusing optics providing a
23°x30° field of view, and a 3-LED illumination module delivering 140mW optical power on the target. The system is
capable of acquiring a stream of 7 3D frames/s with a maximum non-linearity of 3.3% in the range 1.2m-3.7m and a
precision better than 10 cm at 2m and 20 cm at 3m.
In this paper, we report on a new type of CMOS electro-optical modulator (EOM), called Photonic Mixer
Device (PMD), based on the Charge Pumping (CP) phenomenon, which is capable of mixing and accumulating
photo-generated charge-packets synchronously with respect to a pulsed light source. The device uses two PMOS
transistors with embedded photodiode to detect the intensity and phase of a modulated light signal. Using
clocking between accumulation and inversion, the two transistors transfer to output charge packets which are
synchronized and proportional to the light intensity. The device operates at 3.3V with no dc power consumption
and is implemented in a standard 0.35μm CMOS process. Using a 1.5mW/cm2 light source pulsed at 25KHz,
the device estimates a phase delay with an accuracy of 0.8%.
A fast, low power CMOS sensor for optical tracking is presented. The tracking function is carried out by pointing at the target with a collimated light beam and estimating the position of the back-reflected beam portion impinging on the device. An example of optical tracking sensor is represented by a Position Sensitive Detector (PSD). This work presents a novel architecture of a 2D pixel array for single spot detection and tracking, based on image outline extraction. The prototype device, designed in standard 0.8 μm CMOS technology, consists of an array of 20x20 pixels with a pitch of 70.25 μm and a fill factor of 12%. The photosensitive detector is provided with analogue processing circuitry and digital blocks which allow to extract the spot centroid. Two different multiple threshold working modes are adopted in order to improve the sensor accuracy and frame rate. The light spot position can be estimated in 120 μsec with an accuracy of 0.9 μm, when the sensor is operated with the first mode. The second mode is adopted to improve the frame rate. The chip exhibits a worst case power cosumption of 15 mW @ 5 V and a frame rate up to 3000 frames/s.