Optical Crosstalk in InGaAs/InP SPAD Array: Analysis and Reduction with FIB-Etched Trenches

This letter describes the reduction of optical crosstalk by means of focused ion beam-etched trenches in InGaAs/InP single-photon avalanche diode arrays. Platinum-filled trenches have been fabricated in a linear array in order to limit the direct optical crosstalk between neighboring pixels. Experimental measurements prove that optical crosstalk has been reduced by ∼60 % thanks to a strong suppression of direct optical paths. An optical model is introduced in order to describe the main contributions to crosstalk and to validate measurements

InGaAs/InP single-photon detector with low noise, low timing jitter and high count rate

We present a new InGaAs/InP Single-Photon Avalanche Diode (SPAD) with high detection efficiency and low noise, which has been employed in a sinusoidal-gated setup to achieve very low afterpulsing probability and high count rate. The new InGaAs/InP SPAD has lower noise compared to previous generations thanks to the improvement of Zinc diffusion conditions and the optimization of the vertical structure. A detector with 25 μm active-area diameter, operated in gated-mode with ON time of tens of nanoseconds, has a dark count rate of few kilo-counts per second at 225 K and 5 V of excess bias, 30% photon detection efficiency at 1550 nm and a timing jitter of less than 90 ps (FWHM) at 7 V of excess bias. In order to reduce significantly the afterpulsing probability, these detectors were operated with a sinusoidal gate at 1.3 GHz. The extremely short gate ON time (less than 200 ps) reduces the charge flowing through the junction, thus reducing the number of trapped carriers and, eventually, lowering the afterpulsing probability. The resulting detection system achieves a maximum count rate higher than 650 Mcount/s with an afterpulsing probability of about 1.5%, a photon detection efficiency greater than 30% at 1550 nm and a temporal resolution of less than 90 ps (FWHM)

A Single-Photon Imager Based on Microwave Plasmonic Superconducting Nanowire

Detecting spatial and temporal information of individual photons by using single-photon-detector (SPD) arrays is critical to applications in spectroscopy, communication, biological imaging, astronomical observation, and quantum-information processing. Among the current SPDs1,detectors based on superconducting nanowires have outstanding performance2, but are limited in their ability to be integrated into large scale arrays due to the engineering difficulty of high-bandwidth cryogenic electronic readout3-8. Here, we address this problem by demonstrating a scalable single-photon imager using a single continuous photon-sensitive superconducting nanowire microwave-plasmon transmission line. By appropriately designing the nanowire's local electromagnetic environment so that the nanowire guides microwave plasmons, the propagating voltages signals generated by a photon-detection event were slowed down to ~ 2% of the speed of light. As a result, the time difference between arrivals of the signals at the two ends of the nanowire naturally encoded the position and time of absorption of the photon. Thus, with only two readout lines, we demonstrated that a 19.7-mm-long nanowire meandered across an area of 286 {\mu}m * 193 {\mu}m was capable of resolving ~590 effective pixels while simultaneously recording the arrival times of photons with a temporal resolution of 50 ps. The nanowire imager presents a scalable approach to realizing high-resolution photon imaging in time and space

Low Dark Count Rate and Low Timing Jitter InGaAs/InP Single-Photon Avalanche Diode

We describe the design and characterization of a new InGaAs/InP Single-Photon Avalanche Diode (SPAD) for single-photon detection at 1.55 µm with high detection efficiency, low noise and low timing jitter. The design and fabrication have been optimized to reduce the defects (responsible for dark counts and afterpulsing). Zinc diffusion is a key step and we optimized the profile, pattern and reactor parameters to achieve uniform sensitivity in the active area, low noise and low timing jitter. The active area diameter of the device here described is 25 µm and no floating guard rings are present. It is operated in gated mode, with passive quenching, for the characterization. The dark count rate is in the order of few kilo-counts per second at 225 K and 5 V of excess bias. The photon timing resolution, measured as the full-width at half maximum of the response to a 20 ps pulsed laser, is about 90 ps, with a clean exponential tail whose time constant is about 60 ps. The photon detection efficiency is about 30% at 1550 nm. These specifications make our InGaAs/InP SPAD a good candidate for advanced time-correlated single-photon counting applications at wavelengths up to 1700 nm

Die 'Kavaliersanleihe' ein Instrument zur Beschleunigung des Aufbaus in den neuen Bundeslaendern

UuStB Koeln(38)-921102017 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Data file_29thJan16

Experimental results from single photon avalanche photodiodes reported in the manuscript