Optics and Precision Engineering
Improvement of high-gain shot-noise detector
Zhou Hai-ju
Abstract
Based on the special demands of quantum optical experiments for low noise detectors,a high gain and shot noise detector was designed by combing an AC current coupled trans-impedance pre-amplify circuit and an ETX500photodiode.Compared with existing detectors,the designed detector shows better characteristics in gain,bandwidth and AC DC saturation.The output characteristics of the detector were measured by using a 1 064nm single frequency laser as a source and a frequency spectrum analyzer as the measuring instrument.Measuring results show that the power noise spectrum of the detector is 10dB higher than that of electronic noise spectrum when the injecting power for the detector is more than 850μW at 2MHz.Furthermore,the bandwidth of the shot noise detector reaches 5MH when the input infrared laser power is above 1.62mW.The remarkable linearities for the DC and AC currents are available when the input infrared laser power is increased to 36mW.Considering its higher gain and better DC AC saturation characteristics,the detector is advantageous to quantum optic experiments.