High Speed and High Sensitivity InGaAs/InAlAs Single Photon Avalanche Diodes for Photon Counting Communication

A planar InGaAs/InAlAs single photon avalanche diode (SPAD) was fabricated and comprehensively characterized. At room temperature, the dark count rate is 3.1 MHz at 10.4% photon detection efficiency. The corresponding noise-equivalent power of 3.07 × 10
⁻¹⁵
W/Hz
^1/2
is achieved, which is the lowest value among reported InGaAs/InAlAs SPADs operated at room temperature. Moreover, it is the first time to report an InGaAs/InAlAs SPAD driven by a sine wave gate (SWG) quenching circuit as a receiver in the photon counting communication system. For achieving high-bit-rate transmission with high sensitivity, a high-frequency (1.8 GHz) SWG quenching circuit is developed and the time jitter for the system is reduced to 53 ps. At bit rates of 100 Mbit/s, 200 Mbit/s, and 400 Mbit/s, the sensitivities of −57.2 dBm, −53.42 dBm, and −51.06 dBm are experimentally demonstrated with a single InGaAs/InAlAs SPAD respectively. In addition, a theoretical sensitivity of −42.7 dBm is predicted at 1.8 Gbit/s with a 4 × 4 InGaAs/InAlAs SPAD array.