Key Technology Of High-speed Photoelectric Conversion Module

The high-speed optoelectronic conversion technology plays considerable and important roles in various optoelectronic systems such as optoelectronic measurement, optoelectronic control, and optoelectronic radar. However, the relational technologies and the products in domestic markets are hardly dominated by foreign products due to various reasons, so its price is quite high. And the performance of most conversion modules developed independently is constrained, such as low responding speed and bandwidth though able to respond to low frequency signal with high sensitivity, while higher bandwidth but with limited sensitivity and unable to make weak light detection. Therefore, this dissertation introduces certain key technologies about high-speed optoelectronic conversion modules and describes the main principles for and the process of designing a DC-6GHz optical module and its test results.The high-speed optoelectronic conversion module designed in this thesis is characterized by low-noise (output noise voltage of less than3mV), high sensitivity (about2×103V/W), and wide bandwidth (response the frequency from DC to6GHz).The modeling and package of p-i-n photo-diode are first presented in this dissertation. And then, the implementation of the entire module is designed based on the actual situation. The main tasks of this thesis include designing two high-gain and low noise amplifier circuits which can respond the frequency of DC-1.3GHz and1.3GHz-6GHz respectively, and a ultra-broadband diplexer for combining the two channels’ signal of DC-1.3GHz and1.3GHz-6GHz. The amplifier circuits for DC-1.3GHz are implemented by using op-amp THS3202and THS4302as trans-impedance amplifier and main amplifier respectively to get higher gain and lower noise. While, the amplifier circuits for1.3GHz-6GHz are implemented by using a resistive load as trans-impedance amplifier and one-stage E-pHEMT microwave transistor VMMK-1225as main amplifier respectively. Both the two amplifier circuits’ total trans-impedance gain is approximately2.2x10j V/A. The final step is design an ultra-broadband diplexer comprised by an ultra-broadband suspended micro-strip high pass filters and broad-stopband micro-strip low pass filters to form a fractional double terminated quasi-complementary diplexer, meeting the expectations.