Single-photon detection apparatus and method comprising a phase-reversed reflection branch and a phase-unreversed reflection branch

A single-photon detection apparatus comprising a phase-reversed reflection branch, a single-photon sensing device, and a phase-unreversed reflection branch, wherein the single-photon detection apparatus is configured to receive an input signal divided into a first input signal that is received at the phase-reversed reflection branch and a second input signal that is received at the single-photon sensing device;

• the phase-reversed reflection branch is configured to:
• perform phase-reversed reflection processing on the first input signal, to obtain a phase-reversed signal, and send the phase-reversed signal to the single-photon sensing device;
• the single-photon sensing device is configured to send the second input signal to the phase-unreversed reflection branch, and is further configured to:
• sense a photon, generate photon information, and output a first branch signal, wherein the first branch signal comprises the photon information and the phase-reversed signal;
• the phase-unreversed reflection branch is configured to perform phase-unreversed reflection processing on the second input signal, to obtain a second branch signal;
• and
• the first branch signal is superimposed with the second branch signal, to obtain the photon information.