A frequency-tunable gigahertz sinusoidally gated near-infrared single-photon detector

Abstract

The invention discloses a gigahertz sine gating near-infrared single photon detector with a tunable frequency. The gigahertz sine gating near-infrared single photon detector with the tunable frequency comprises a light source, a sine gating APD module, a direct-current bias voltage stabilizing source, an electro-optical modulator, a photoelectric detector, a low pass filter and a discriminator, wherein continuous light emitted by the light source serves as light input of the electro-optical modulator, the electro-optical modulator modulates the light input under the common action of direct-current bias and sine gating APD avalanche signals, light signals which are modulated by the electro-optical modulator are converted by the photoelectric detector into electric signals to be output, the low pass filter is used for filtering sine gating noise signals in the electric signals and outputting the avalanche signals, and the discriminator counts the received avalanche signals and counts single photon input. Noise produced in the coupling process of avalanche photoelectric diode APD junction capacitors can be effectively restrained without a band elimination filter and other devices, and the gigahertz sine gating near infrared single photon detector with the tunable frequency has the advantages of reducing the dark count and the after-pulse probability, being compact in structure, having no requirement for the ultra-low temperature, and the like.

Description

technical field [0001] The invention relates to a near-infrared band single-photon detector, in particular to a frequency-tunable gigahertz sinusoidal gated near-infrared band single-photon detector, which belongs to the fields of near-infrared quantum secure communication and weak optical signal detection. . Background technique [0002] Single photon detection technology can be widely used in quantum key distribution (QKD), laser radar (lidar), fiber optic sensing (fiber optical sensing), fiber optic communication (fiber optical communication) and other fields. Single-photon detection by sinusoidally gated avalanche photodiode is a commonly used method. By increasing the bias voltage of avalanche photodiode APD only when the photon arrives, the detection rate can be greatly improved and the dark area can be reduced under the premise of ensuring the detection efficiency. Count the probability of occurrence. [0003] However, due to the high-pass coupling characteristics o...

AI Technical Summary

Problems solved by technology

But its detection rate is fixed, determined by the filter center frequency

Therefore, the adaptability of its detection rate is not strong. Once the detector is designed, its working rate is fixed and its flexibility is poor.

And because the geometric size of high-performance filters is usually compared with the wavelength, for gigahertz detectors, the delay line or filter size is more than tens of centimeters, so that the entire detector system is still bulky, which is not conducive to portable field application

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