| When avalanche photoelectric diodes (APD) are operated above the breakdown voltage in Geiger mode, they can be used to detect single photon. Therefore, APD-based single photon detectors are wildly used in the fields of quantum information and weak light detection areas. In particular, InGaAs/InP APDs cover the 1100nm -1650nm wavelength range, which can be used for measuring single photon at telecom-band.In the thesis, we developed an InGaAs/InP APD based single photon detector, which consists of an APD, bias voltage circuit, amplifier and discriminator circuit,counter. The APD was operated in the gated Geiger mode. When the gate width was 2 ns, we obtained 9.1% quantum efficiency at 1550 nm band with the noise equivalent power of 4.0×10-15 W/Hz1/2 and dark count probability of 8.1×10-3 counts/pulse, respectively. Testing the detector by varying the bias voltage and the threshold of the discriminator, we found the optimum noise equivalent power can be achieved by adjusting these two parameters carefully. Also, we compared different single photon detectors by using the metric, which is defined as the noise-equivalent power divided by the repetition frequency, the results show that our system is suitable for detecting pulsed single-photon at the telecom-band and the system performance will be improved if some measures are taken to suppress the after-pulse effect. |
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