On-chip Squeezed Lights Based On Optical Parametric Oscillation In High-Q Microtoroid Resonators

Squeezed light has developed for more than 30 years as a non-classical quantum light sources. In 1985, four wave mixing in atomic vapor was performed to produce squeezed light for the first time. So far, the degree of squeezing was increasing all the time, from 7% originally to almost 12.7 dB. Squeezed light sources have been widely used in a large amount of areas, such as weak signal detection and quantum communication. It breaks the restrictions caused by the standard quantum limit. Although squeezed light has achieved great success, it is also facing a very important challenge. For example, more in-depth experiments need a lot of optical components. As a result, the systems as well as their operation will become more and more complicated. In order to overcome these difficulties, people gradually turn their attention to integrated photonics. The miniaturization of devices allows people to control more photonic circuits at the same time. The development of micro/nano technology makes the miniaturization of squeezed light source possible. On-chip integrated squeezed light source has the advantages of small size and high reliability. Smaller size means more broad application, for example, the quantum computation and quantum information processing. So it is very necessary to study the chip-based squeezed light source.The realization of squeezed light is mainly based on optical nonlinear process, such as optical parametric amplification, four wave mixing, and so on. Due to the high quality factor and small mode volume the generation of the nonlinear process in microcavity is easier. Therefor, additional noise in the process can be avoided.The main purpose of this thesis is to study the integrated squeezed light source. We accomplished twin beams with highly strong correlations by parametric oscillation in the chip-based whispering gallery micro-cavity. Firstly, parametric oscillation in the on-chip whispering gallery micro-cavity together with intensity difference squeezing between signal light and idler light has been carried on the theoretical analysis. Besides, the quantities which influences the degree of squeezing was studied. Then we operated the optical parametric oscillation above the threshold and achieved a pair of signal and idler with certain frequency difference. Also we the optimized the low loss optical path to measure the squeezed light. Finally we realized the intensity difference squeezing by optimizing the experimental parameters such as the back-scattering in the microtoroid and the insertion loss in the optical path. The experimental results were analyzed for further improving the degree of the squeezing.