Key Techniques For Photonic Microwave Receiving In ROF Systems

The paper is mainly concerning on designing a novel LiNbO₃ microdisk based photonic microwave receiver, which plays an important part in a Radio Over Fiber (ROF) system. Compared with a traditional microwave receiver, the photonic microwave receiver has many advantages, such as small volume, simple structure, little electrical consumption and easiness to be built in or removed, which meets the new direction for modern communication systems' development.The high-Q Whispering-Gallery Modes (WGMs) in the microdisk are receiving more and more attention in many areas from basic physics to optical communication because of their unique characters. Grounded on the WGMs and the resonance of microwave, we can design novel modulators with high modulation efficiency and microwave sensors with high sensitivity. Through theoretical analysis and experiment, we investigate the optical characterization of the microdisk systemically. Based on this investigation, we propose a novel electrooptic modulator with high modulation efficiency. We use a prism to couple the light to the microdisk and try many methods to increase the coupling efficiency. We also propose a novel electrode structure for the modulator which increases the modulation efficiency significantly.The antenna-coupled electrooptic modulator is a brightly new area in microwave photonics, and it is also the key step to design an integrated photonic microwave receiver. In this paper, we propose to directly use the electrode of the modulator as the feed line of the dielectric resonator antenna. In order to reduce the volume of the whole device, we also try coupling the received electric field from the dielectric resonator to the electrode through a narrow aperture, and propose a novel structure based on the aperture coupling method. The simulation results show these structures perform well.