Low-Noise InGaAs/InP Single-Photon Avalanche Diodes for Fiber-Based and Free-Space Applications

We present the design and experimental characterization of a new InGaAs/InP single-photon avalanche diode (SPAD), with two different diameters: i) 10 ?m device, suitable for optical fiber-based quantum applications; ii) 25 one, more appropriate free-space applications. Compared to previous generation, we improved double zinc diffusion optimized layer structure. achieved low dark count rate, around 1 kcps 4 at 225 K 5 V excess bias devices, respectively, down few tens counts per seconds 175 detector. At temperature, both devices also show high photon detection efficiency (33% 1064 nm, 31% 1310 nm 25% 1550 SPAD). Afterpulsing has been measured custom readout integrated circuit, achieving very probability values. Timing jitter is comparable previous-generation devices.