物理学报Issue(19)：1-6,6.DOI:10.7498/aps.63.194206
通信波长频率一致纠缠光源的频谱测量
Measurement of the sp ectral prop erties of the coincident-frequency entangled biphoton state at optical communication wavelength
摘要
Abstract
The frequency entangled biphoton source generated via spontaneous parametric down-conversion (SPDC) process has found important applications in the fields of quantum clock synchronization, quantum communication, quantum information processing, etc. As quantum technologies evolve, quantitative characterization of the frequency entanglement becomes necessary and has been implemented by measuring the spectral properties of the biphoton state. However, due to the high dark rate and low quantum efficiency of the InGaAs single-photon detectors, direct measurement of the spectral properties of the biphoton state at optical communication wavelength is hard to implement. In this paper, we report the measurement of the spectral properties of a biphoton state at optical communication wavelength which is generated from periodically poled potassium titanyl phosphate (PPKTP) pumped by an ultra-short pulsed optical source at 787 nm. Based on the coincidence measurement setup together with two infrared spectrometers, the spectra of the signal and idler photons are obtained with their center wavelengths being 1574.4 nm and 1574.9 nm, while their 3-dB bandwidths being 35.3 nm and 37.6 nm respectively. The joint spectrum of the photon pair is observed as well and shows a coincident-frequency entanglement and a joint spectrum bandwidth of 3 nm. According to the ratio of the single-photon spectral bandwidth to the joint spectral bandwidth of the photon pairs, the degree of frequency entanglement is quantified to be 12, denoting a relatively high quality of the entanglement.关键词
量子纠缠/联合频谱/频率正关联Key words
quantum entanglement/joint spectrum/coincident-frequency entanglement引用本文复制引用
王盟盟,权润爱,邰朝阳,侯飞雁,刘涛,张首刚,董瑞芳..通信波长频率一致纠缠光源的频谱测量[J].物理学报,2014,(19):1-6,6.基金项目
国家自然科学基金(批准号：Y133ZK1101,11174282,91336108)、中科院“西部之光”计划重点项目(批准号:中科院人教字(2011)180号)、科技创新“交叉与合作团队”项目(批准号:中科院人教字(2012)119号)和中组部“青年拔尖人才支持计划”项目(批准号:组厅字[2013]33号)资助的课题.* Project supported by the National Natural Science Foundation of China (Grant Nos. Y133ZK1101,11174282,91336108), the key fund for the “Western light” Talent Cultivation Plan of the CAS, China, and the ”Cross and Cooperative” Science and Technology Innovation Team Project of the CAS, China （批准号：Y133ZK1101,11174282,91336108）
