A method to measure the end-output coupling efficiencies between silicon wire waveguides(SWWs)and optical fibers is proposed and demonstrated.The end-output coupling efficiency is calculated through four measured coun...A method to measure the end-output coupling efficiencies between silicon wire waveguides(SWWs)and optical fibers is proposed and demonstrated.The end-output coupling efficiency is calculated through four measured counting rates based on the correlated photon pair generation in the SWW.It provides a way to investigate and optimize the coupling processes at the input and output end of the optical waveguides separately.展开更多
The size distribution of Si-nanocrystals(Si-ncs)in evenly annealed SiO is investigated with transmission electron microscopy(TEM),x-ray diffraction(XRD),and Raman scattering.Two groups of Si-ncs with very different mo...The size distribution of Si-nanocrystals(Si-ncs)in evenly annealed SiO is investigated with transmission electron microscopy(TEM),x-ray diffraction(XRD),and Raman scattering.Two groups of Si-ncs with very different most probable diameters are identified,where one is>6nm and the other one is<2nm.Both of them increase gradually with increasing annealing temperature.Such a phenomenon is observed directly by TEM for samples with larger Si-ncs(>10nm)and it can be revealed clearly for all samples by Raman spectra with two components(~500cm^(-1)and~520cm^(-1)).The results of XRD show the average effect.The experimental results indicate that the common assumption of Si-nc size distribution with single most probable diameter is not always proper and the possible mechanisms are briefly discussed.展开更多
A high-quality heralded single-photon source (HSPS) at 1.5 μm is experimentally demonstrated based on spontaneous four wave-mixing in a piece of dispersion-shifted fiber cooled by liquid nitrogen.To improve the up-li...A high-quality heralded single-photon source (HSPS) at 1.5 μm is experimentally demonstrated based on spontaneous four wave-mixing in a piece of dispersion-shifted fiber cooled by liquid nitrogen.To improve the up-limit of the preparation efficiency of the HSPS,commercial dense wavelength-division multiplexing components are used to reduce the loss of the filtering and splitting system between the fiber and the single-photon detectors.As a result,a preparation efficiency of 80% is realized under a g(2)(0) of 0.06 in our HSPS experimental system,which is the best performance for the fiber-based HSPS at 1.5 μm reported so far.展开更多
A theoretical model of the self sum-frequency-mixing(SFM)laser generated by a single crystal is proposed,in which spatial distribution of the pump and circulating fundamental lasers with arbitrary beam waists are take...A theoretical model of the self sum-frequency-mixing(SFM)laser generated by a single crystal is proposed,in which spatial distribution of the pump and circulating fundamental lasers with arbitrary beam waists are taken into account.The model is then applied to two kinds of crystals of current interest,Nd:YAI_(3)(BO_(3))_(4) and Nd:Ca_(4)GdO(BO_(3))_(3).Numerical analyses of the self-SFM laser properties predict and confirm some experimental results.The model proposed is not limited to self-SFM lasers and may be applied to general analyses of the fundamental or nonlinear laser generation with Gaussian beams.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00303 and 2010CB327606the Tsinghua University Initiative Scientific Research Program+1 种基金the Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technologythe Postdoctoral Science Foundation of China.
文摘A method to measure the end-output coupling efficiencies between silicon wire waveguides(SWWs)and optical fibers is proposed and demonstrated.The end-output coupling efficiency is calculated through four measured counting rates based on the correlated photon pair generation in the SWW.It provides a way to investigate and optimize the coupling processes at the input and output end of the optical waveguides separately.
基金Supported in part by the National Basic Research Program of China under Grant Nos 2011CBA00608 and 2007CB307004the National Natural Science Foundation of China under Grant Nos 60877023 and 61036010.
文摘The size distribution of Si-nanocrystals(Si-ncs)in evenly annealed SiO is investigated with transmission electron microscopy(TEM),x-ray diffraction(XRD),and Raman scattering.Two groups of Si-ncs with very different most probable diameters are identified,where one is>6nm and the other one is<2nm.Both of them increase gradually with increasing annealing temperature.Such a phenomenon is observed directly by TEM for samples with larger Si-ncs(>10nm)and it can be revealed clearly for all samples by Raman spectra with two components(~500cm^(-1)and~520cm^(-1)).The results of XRD show the average effect.The experimental results indicate that the common assumption of Si-nc size distribution with single most probable diameter is not always proper and the possible mechanisms are briefly discussed.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CBA00303 and 2010CB327606Tsinghua University Initiative Scientific Research Program and Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technology(TNList)。
文摘A high-quality heralded single-photon source (HSPS) at 1.5 μm is experimentally demonstrated based on spontaneous four wave-mixing in a piece of dispersion-shifted fiber cooled by liquid nitrogen.To improve the up-limit of the preparation efficiency of the HSPS,commercial dense wavelength-division multiplexing components are used to reduce the loss of the filtering and splitting system between the fiber and the single-photon detectors.As a result,a preparation efficiency of 80% is realized under a g(2)(0) of 0.06 in our HSPS experimental system,which is the best performance for the fiber-based HSPS at 1.5 μm reported so far.
基金Supported by Fujian Provincial Natural Science Foundation of China(No.A9910019)Fujian Provincial International Cooperation Foundation of China(No.99-1-7)Foundation of Chinese Academy of Sciences for Outstanding Returned Scholars.
文摘A theoretical model of the self sum-frequency-mixing(SFM)laser generated by a single crystal is proposed,in which spatial distribution of the pump and circulating fundamental lasers with arbitrary beam waists are taken into account.The model is then applied to two kinds of crystals of current interest,Nd:YAI_(3)(BO_(3))_(4) and Nd:Ca_(4)GdO(BO_(3))_(3).Numerical analyses of the self-SFM laser properties predict and confirm some experimental results.The model proposed is not limited to self-SFM lasers and may be applied to general analyses of the fundamental or nonlinear laser generation with Gaussian beams.