Research Of Linearization For High-frequency Analog Photonic Link

Analog Photonic Link (APL) is the essential part of Microwave Photonics, converging microwave and photonics technologies. The transmission and processing of microwave signal in optical domain are realized, taking advantages of photonics, such as immunity to electromagnetic interference, high isolation, and low loss.In this thesis, the performance of APL has been researched through theoretical derivation and, simulation analysis. A nonlinear distortion compensation scheme for the intensity-modulated APL based on post digital signal processing has been proposed and experimentally demonstrated, In addition, a photonic microwave frequency down-conversion approach based on integrated Dual Parallel Mach-Zehnder Modulator (DPMZM) has been proposed. Incorporating digital post compensation technique, third-order intermodulation distortion (IMD3) has been suppressed successfully for high frequency signal. The works in this dissertation include:1. Theoretical derivation and simulation analysis of APLs’ performanceIn this thesis, a set of parameters have been introduced to describe the performance of intensity-modulation direct-detection (IMDD) APL with Mach-Zehnder Modulator (MZM), including gain, noise figure and dynamic range. The detailed definitions of these parameters are introduced, as well as the relationships among these parameters and their main effecting factors, such as input optical power to the modulator, modulator half-wave voltage and modulator bias angle. According to the simulation results, several approaches to optimize the performance of APL have been identified.2. IMD3suppression technology based on digital signal processingAn IMD3suppression scheme for the intensity-modulated APL based on digital signal processing has been proposed, as well as theoretically analyzed and experimentally demonstrated. The transfer characteristics of intensity modulator used in our experiment has been measured. The functions of the output fundamental signal power and IMD3power with input signal power have been also obtained. Using this scheme, IMD3components have been suppressed about20dB. However, this scheme is frequency limited, performance deteriorating with signal frequency increasing.3. Photonic microwave frequency down-conversion approach based on integrated Dual Parallel Mach-Zehnder ModulatorA photonic microwave frequency down-conversion approach based on integrated DPMZM has been proposed. Incorporating digital post compensation technique, IMD3has been suppressed successfully for high frequency signal. The conversion performance can be tuned flexibly by simply adjusting bias voltages of the modulator, local oscillator (LO) power and optical power. The influence of these parameters on the conversion efficiency have been theoretically analyzed and experimentally verified. At the same time, the transmission of vector signal in this photonic frequency downconversion links has been experimentally demonstrated. The dependence of transmission performance on carrier frequency and LO power has also been analyzed experimentally.