Study On The Silicon-based Integrated Microwave Photonics

Microwave photonics bringing together the fields of radio frequency engineering and optoelectronics, which utilized the photonic advantages of large bandwidth, tenability and electromagnetic interference immunity, could achieve key functionalities that are either very complex or even not directly possible in microwave domain. While at the same time, it has succeeded in creating new opportunities for information and communication systems. It has found wide applications in wireless access networks, phase array antennas, radio astronomy, high quality TV, and terahertz technology. It mainly achieve three functions including microwave, millimeter wave and THz signal generation, distribution and processing. The microwave photonics will face many challenges in the future, which will demand ever-increasing values for speed, bandwidth, processing capability and dynamic range while, at th same time, will need devices or systems which are small, lightweight and low power consumption, exhibiting large tenability and strong immunity to electromagnetic interference. Then a new research field referred as integrated microwave photonics aiming to achieve microwave photonics system integration on chip is proposed. Up to now, integrated optoelectronics has gained rapid development. The integration cuiruit has been achieved on different integrated materials such as ?-? (InP), SOI, Si3N4, glass, polymer and metal plasma. In this paper, our research mainly concentrates on SOI material, designing and fabricating high-performance silicon devices which can be utilized in microwave, millimeter wave and THz signal generation, distribution and processing. The main contribution and innovation of our works are listed as follows:1. Microwave signal generation:(1). Heterogeneously integrated ?-?/Silicon dual-mode distributed feedback laser for terahertz generation.0.357 THz signal are successfully generated with power of -30 dBm, linewidth of 4.2 MHz, signal to noise ratio of above 40 dB, jitter of 28 MHz. It can carry 20 GHz baseband signal. It features good robustness against bias current (73 mA-105 mA) and temperature instabilities (15?-30?). (2). Microwave signal generation integration on chip based on external modulation. It's the first time to use silicon ring modulator to achieve frequency upconvertion. When input signal of 10 GHz is applied to modulator,20 GHz signal is generated after photodetector, harmonic suppression ratio is above 20 dB.2. Microwave signal distribution. (1). High-speed silicon modulator's nonlinearity analysis utilized in radio-over-fiber system. Carrier dispersion effect nonlinear model of silicon Mach-Zehnder modulator is built. The nonlinear relationship between the effective index and driving voltage is calculated by Silvaco and Matlab software. We analyze this nonlinearity's effect on the UWB and DPSK signal's transmission performance, including phase noise, chirp and dispersion penalty. (2). High-speed silicon modulator's nonlinearity improvement utilized in radio-over-fiber system. Two-beam interference based ring modulator is designed and fabricated to improve nonlinearity of modulator. The nonlinearity of fano curve can eliminate the nonlinearity of carrier dispersion effect, and then 3rd order intermodulation is reduced and dynamic range of link is increased.3. Microwave signal processing. Instantaneous microwave frequency estimation systems are carried out with two integrated silicon ORRs. The one with a low Q factor of 3974 enables a large bandwidth from 0.5 GHz to 35 GHz, while the other one with a high Q factor of 25833 offers a high accuracy better than 0.1 GHz.