Testing And Analysis Of Frequency Response Of High-Speed Optoelectronic Devices

With the rapid development of information science,the Internet of Things,5G communication,cloud computing and driverless technologies have emerged,which will drive the exponential growth of information carrying capacity as well as transmission rate of communication networks.As an important support for modern communication networks,optical communication systems will face the challenge of large capacity and high speed,and optoelectronic devices are the key components of optical communication systems,and their performance will need to meet the higher development requirements.These properties must be obtained through the testing of optoelectronic devices.In addition the structure optimization and design of the device is also inseparable from the accurate measurement of core parameters.The frequency response of optoelectronic devices is one of the core parameters,and its good or bad will directly represent the high speed performance of the device.As the frequency response bandwidth of optoelectronic devices increases,the frequency domain test results must be more accurate in order to better bring feedback suggestions for device structure design and process condition optimization.This thesis focuses on the frequency response testing of high performance optoelectronic devices and the method of post-test parameter extraction,the main work and research results are as follows.1.The commonly used test methods for frequency response of optoelectronic devices are compared and analyzed,and the advantages and disadvantages of each are described.The sweep method is one of the mainstream test methods for optoelectronic devices due to its simple system and convenient and fast test process.A detailed analysis of the frequency response test experiment of an avalanche photon diode(APD)is done based on the sweep method.2.A frequency response test system for optoelectronic devices based on optical wave device analyzer was built to complete the test experiments on the-3dB bandwidth of the high-speed characteristics of semiconductor lasers and photodetectors.By analyzing the test results of the photodetector,comparing two calibration processes,the first one,the calibration plane in the coaxial reference plane;the second one,the calibration plane in the on wafer reference plane,it is found that the reflection curve tested after the second calibration method is smoother,so the on wafer reference plane is used as the calibration plane,and after conducting several experiments,the on chip of the optoelectronic device is summarized and improved.After the same photodetector chip was tested separately,it was found that the measured frequency response bandwidth was 18.38GHz before the improvement,and 22.29GHz after the improvement,which is about 20%higher.3.By improving the traditional genetic algorithm,a method to obtain the key parameters of semiconductor photodetector is proposed.First,based on the equivalent circuit model of PIN photodetector,the Sparameter calculation model of PIN is derived by combining the circuit structure and scattering parameter theory.Then,the traditional genetic algorithm is improved,and the S-parameter calculation model of PIN photodetector is brought into the improved genetic algorithm to calculate the values of each parameter of the equivalent circuit.After repeated validation,the improved genetic algorithm can obtain satisfactory results after only 100 cycles,while the traditional genetic algorithm requires more than 200 cycles to reach convergence,with a 50%improvement in efficiency.The experiments prove that this improved genetic algorithm is fast and effective for parameter extraction.