Analysis Of The Characteristics Of APD Receiving Assembly

APD receiving assembly is often used as a key device of the receiver in high-speed optical fiber communication systems due to its advantages of internal gain and wide bandwidth. Performances of APD directly determine the performances of the receiver, such as the length of the communication distance, the number of relay stations and the size of the bit error rate of signal transmission. Thus the analysis of the characteristic of APD receiving assembly is necessary.Firstly, the current development situation of APD optical receiver assembly at home and abroad was introduced, as well as the background and significance of this study. The structures, working-principle and types of APD were described, and the advantages and disadvantages of different trans-impedance amplifiers were analyzed too; Secondly, the specific parameters and their influence factors of the APD receiving assembly were discussed in detail. The influence of irradiance and dark current on the sensitivity of APD was analyzed theoretically. Furthermore, we designed and built the testing system for testing the characteristics of the receiving assembly. Finally, the temperature test, accelerated aging test and sensitivity test were carried out base on the testing system. The results of temperature test showed that the influence of temperature on the breakdown voltage was linear with an influence factor of about 0.054V/℃, whereas the influence of temperature on the dark current presented exponential relation. The result of accelerated aging test showed that the electrical and optical parameters of the device presented no significant changes before and after the aging test, thus the reliability of the device was very good. Through the sensitivity test, we found that the smaller the dark current, the lower the value of sensitivity. The results of the sensitivity test showed that the single-ended output resistance matching the transmission line resistance when the load resistance was 49.8?, the value of the sensitivity of device is -32.01dBm, and the light-power that could be detected was 0.63uw.