The Basic Research On Photonic Microwave Generation Of Optical Injected And Optical Feedback Semiconductor Laser

With the rapid development of the mobile Internet, there is an increasing demand in bandwidth and speed for wireless communication. However, in the conventional wireless communication system, only the low- frequency subcarrier can be used with a limited bandwidth, due to the high propagation loss for the high-frequency electromagnetic wave traveling through the free space. To meet the growing demand for bandwidth and speed in wireless communication, the radio-over-fiber(RoF) communication technology has been proposed. The RoF can link up the optical fiber communication system and the conventional wireless communication, and has been highly developed over the past two decades. The RoF intends to use the optical fiber communications with a huge bandwidth, to offer the bandwidth that the wireless communication needs. Wherein, the photonic microwave generation technology is one of key technologies in the RoF system, and form up the foundation for the RoF. Therefore, it is absolutely necessary to study how to obtain microwave signal by employing photonic technology.This thesis focuses on the issue of generating photonic microwave based on the nonlinear dynamics of semiconductor lasers. As a basic device in modern optoelectronic information domain, the semiconductor laser is widely used in communication system, especially in the optical fiber communications.Main content of this thesis is as below:1. The background, technical principle and advantages of RoF system are introduced. Several kinds of technology to generate photonic microwave and theirs advantages &disadvantage are presented. The research progress of photonic microwave generation based on the nonlinear dynamics of the semiconductor lasers is overviewed.2.The basic principle of semiconductor laser is introduced. Then the rate equations are derived for semiconductor lasers under free-running, optical injection and optical feedback, respectively.3.The basic nonlinear dynamics of the semiconductor laser are numerically simulated. The impact of injecting light on period-one oscillation generated photonic microwave is analyzed in detail. Consequently, the basic characteristics of period-one photonic microwave are concluded and discussed.4. Generating photonic microwave by exploring the nonlinear dynamics of semiconductor laser is experimentally studied. The impact of external injection strength, detuning frequency and the bias current of the slave laser on the period-one oscillation generated photonic microwave is experimentally verified and discussed. Because the period-one photonic microwave has a relatively large linewidth only under external injection, optical feedback is introduced to narrow the microwave linewidth. As a result, the linewidth is reduced from around 10 MHz without optical feedback to around 130 kHz with optical feedback.