Research on Integrated Quantum Photonic Devices

研究了利用光子特性在未来量子信息通信系统中应用的新型量子光子器件。所得结果总结如下：1。对非线性光相互作用（NLO）进行量子理论分析，包括二次谐波产生（SHG）、和频和差频产生（SFG/DFG）、参数荧光（PF），计算输出光束的量子噪声和相关性，建立器件设计技术。对分布式布拉格反射器（DBR）半导体激光器进行了量子理论分析，阐明了量子噪声抑制和压缩特性的条件。建立了制备LiNbO_3波导和准相位匹配（QPM）结构的技术。提出了一种在MgO:LiNbO_3晶体中形成QPM结构的周期性紫外光照射和电压应用新技术。设计并制作了采用LiNbO_3波导的原型器件。利用反向质子交换技术将波导埋置以提高效率。在SHG/DFG装置中，效率高达1400%/W。设计并制作了两种用于产生平行偏振和交叉偏振双光子的LiNbO_3波导QPM NLO器件，并通过实验证明了其性能接近理论预测和双光子的量子相关性。设计并制作了用于压缩光产生的DBR激光器。获得了高达70%的量子效率，并证明了产生噪声水平低于标准量子极限0.8dB的压缩光。实验研究了两台低噪声DBR激光器产生量子相关双光束的可能性。

Research work was performed on novel quantum photonic devices for applications in future quantum information communication systems using photon properties. The obtained results are summarized as follows :1.Quantum theory analysis was performed on nonlinear-optic (NLO) interactions including second-harmonic generation (SHG), sum and difference frequency generations (SFG/DFG), parametric fluorescence (PF) to calculate quantum noises and correlations of the output beams and establish the device design techniques.2.Quantum theory analysis was performed on distributed Bragg reflector (DBR) semiconductor lasers to clarify the conditions for quantum-noise suppression and squeezing characteristics.3.Techniques for fabrication of LiNbO_3 waveguide and quasi-phase matching (QPM) structures were established. New technique using periodic ultraviolet light irradiation and voltage application was developed for formation of QPM structures in MgO:LiNbO_3 crystals.4.Prototype devices using LiNbO_3 waveguides were designed and fabricated. Waveguides were buried by reverse proton-exchange technique for efficiency enhancement. Efficiencies as high as 1400%/W were accomplished in SHG/DFG devices.5.Two types of LiNbO_3 waveguide QPM NLO devices for generation of parallel- and cross- polarized twin photons were designed and fabricated, and the performances close to the theoretical predictions and quantum correlation of the twin photons were experimentally demonstrated.6.DBR lasers for squeezed light generation were designed and fabricated. Quantum efficiencies as high as 70% was obtained, and generation of squeezed light with noise level 0.8dB below the standard quantum limit was demonstrated.7.Generation of quantum-correlated twin beams by two low-noise DBR lasers was experimentally studied, and the possibility was demonstrated.