Research On Photodetector In Inter-satellite Laser Ranging System

Inter-satellite laser ranging system is one of the key technologies in the gravitational waves detection mession, the Earth's gravity recovery and the next generation of satellite based earth gravity measurement with low-low satellite-to-satellite tracking. The use of inter-satellite laser ranging implies that, there should be an element which receives the laser signal and transforms it into electrical signal, i.e. photoreceiver. In particular, the performance of the photoreceivers definitely have a significant impact on low-noise detection and phase measurements.According to the specifications required in the projects, such as high-bandwidth and ultra-low noise, we have fulfilled the design of the transimpedance amplifier circuits for the photoreceiver. For inter-satellite ranging, the noise of photoreceiver will results in phase noise or displacement measurement noise. In order to reduce as much as possible the noise while maintaining the required specifications of the photoreceiver, we studied the working principles of the photoreceiver operation. In this thesis, we discussed the electrical characteristics of the circuits, identified the noise sources and the frequency response of the devices. We established the noise model of the photoreceiver and discussed the selection of the key components. From the result of the simulation for the transimpedance amplifier circuits, the-3dB bandwidth is around 38 MHz that is lower than the theoretial prediction, the spectrum density of the equivalent input current noise is 1.35 pA/?Hz that is better than the limit of 3 pA/?Hz below 30 MHz.In order to understand further the noise in more detail, we suggested a scheme for testing the noise and transfer function of the transimpedance amplifier performance(Mock-up TIA board). Besides the conventional transfer function measurement methods based on Network Analyzer and Spectrum Analyzer, we have proposed two new methods by means of ADC sampling and DPLL sweeping. Additionally, through the mesurments of the output voltage noise and the transfer function of the mock-up TIA board, the equivalent input current noise density is determined.For the experimental part, we have completed the optical power calibration and noise measurement. All of the testings meet the requirements of the photoreceiver designed. Compared the results of noise measurements conducted on different photoreceiver prototypes, we also discussed the noise sources in low frequency range and in high frequency range.