A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated. The filter tunability is achieved by rotating the pol...A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated. The filter tunability is achieved by rotating the polarization controller. The spectral shift is dependent on rotation direction and the position of the polarization controller. In addition, the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.展开更多
针对多模光纤高频区深衰落点对正交频分复用系统性能的影响,采用光信噪比门限的分配算法的自适应调制技术进行改进,通过算法与调制过程的实验结果,得出:设计的算法有效地实现了自适应调制选择,在信道特性较好时使用高阶调制多传信息,在...针对多模光纤高频区深衰落点对正交频分复用系统性能的影响,采用光信噪比门限的分配算法的自适应调制技术进行改进,通过算法与调制过程的实验结果,得出:设计的算法有效地实现了自适应调制选择,在信道特性较好时使用高阶调制多传信息,在出现的信道特性较差时降低调制阶数少传甚至不传信息,减少了系统误码率。对比实验表明:在相同误码率条件下,与不使用自适应调制技术的系统相比改进系统光信噪比要低2 d B左右;改进系统传输性能更好,实现更为简单。将算法系统应用到火灾报警当中,得出:多模光纤传输能够有效的检测能量损失及损耗点的大体位置,能够准确实现火情的传输。这一研究对于我国无线网络的发展有一定的实际意义。展开更多
Entanglement distribution between distant parties is one of the most important and challenging tasks in quantum communication.Distribution of photonic entangled states using optical fiber links is a fundamental buildi...Entanglement distribution between distant parties is one of the most important and challenging tasks in quantum communication.Distribution of photonic entangled states using optical fiber links is a fundamental building block toward quantum networks.Among the different degrees of freedom,orbital angular momentum(OAM)is one of the most promising due to its natural capability to encode high dimensional quantum states.We experimentally demonstrate fiber distribution of hybrid polarization-vector vortex entangled photon pairs.To this end,we exploit a recently developed air-core fiber that supports OAM modes.High fidelity distribution of the entangled states is demonstrated by performing quantum state tomography in the polarization-OAM Hilbert space after fiber propagation and by violations of Bell inequalities and multipartite entanglement tests.The results open new scenarios for quantum applications where correlated complex states can be transmitted by exploiting the vectorial nature of light.展开更多
A novel phase-shifted long-period fiber grating(PS-LPFG)for the simultaneous measurement of torsion and temperature is described and experimentally demonstrated.The PS-LPFG is fabricated by inserting a pretwisted stru...A novel phase-shifted long-period fiber grating(PS-LPFG)for the simultaneous measurement of torsion and temperature is described and experimentally demonstrated.The PS-LPFG is fabricated by inserting a pretwisted structure into the long-period fiber grating(LPFG)written in single-mode fiber(SMF).Experimental results show that the torsion sensitivities of the two dips are?0.114 nm/(rad/m)and?0.069 nm/(rad/m)in the clockwise direction,and?0.087 nm/(rad/m)and?0.048 nm/(rad/m)in the counterclockwise direction,respectively.The temperature sensitivities of the two dips are 0.057 nm/℃ and 0.051 nm/℃,respectively.The two dips of the PS-LPFG exhibit different responses to torsion and temperature.Simultaneous measurement of torsion and temperature can be implemented using a sensor.The feasibility and stabilization of simultaneous torsion and temperature measurement have been confirmed,and hence this novel PS-LPFG demonstrates potential for fiber sensing and engineering applications.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11274181,10974100,and 10674075)the Tianjin Key Program of Application Foundations and Future Technology Research Project,China (Grant No. 10JCZDJC24300)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120031110033)
文摘A novel tunable comb filter composed of a single-mode/multimode/polarization-maintaining-fiber-based Sagnac fiber loop is proposed and experimentally demonstrated. The filter tunability is achieved by rotating the polarization controller. The spectral shift is dependent on rotation direction and the position of the polarization controller. In addition, the adjustable range achieved by rotating the half-wave-plate polarization controller is twice higher than that of the quarter-wave-plate one.
文摘针对多模光纤高频区深衰落点对正交频分复用系统性能的影响,采用光信噪比门限的分配算法的自适应调制技术进行改进,通过算法与调制过程的实验结果,得出:设计的算法有效地实现了自适应调制选择,在信道特性较好时使用高阶调制多传信息,在出现的信道特性较差时降低调制阶数少传甚至不传信息,减少了系统误码率。对比实验表明:在相同误码率条件下,与不使用自适应调制技术的系统相比改进系统光信噪比要低2 d B左右;改进系统传输性能更好,实现更为简单。将算法系统应用到火灾报警当中,得出:多模光纤传输能够有效的检测能量损失及损耗点的大体位置,能够准确实现火情的传输。这一研究对于我国无线网络的发展有一定的实际意义。
基金P.Kristensen from OFS-Fitel for the fiber fabrication,and D.Poderini for many advices on the software development.Funding Information:This work was supported by the Center of Excellence,SPOC-Silicon Photonics for Optical Communications(ref DNRF123)by the People Programme(Marie Curie Actions)of the European Union’s Seventh Framework Programme(FP7/2007-2013)under REA grant agreement no.609405(COFUNDPostdocDTU)+1 种基金and by the ERC-Advanced grant PHOSPhOR(Photonics of Spin-Orbit Optical PhenomenaGrant Agreement No.694683).G.C.acknowledges Becas Chile and Conicyt.
文摘Entanglement distribution between distant parties is one of the most important and challenging tasks in quantum communication.Distribution of photonic entangled states using optical fiber links is a fundamental building block toward quantum networks.Among the different degrees of freedom,orbital angular momentum(OAM)is one of the most promising due to its natural capability to encode high dimensional quantum states.We experimentally demonstrate fiber distribution of hybrid polarization-vector vortex entangled photon pairs.To this end,we exploit a recently developed air-core fiber that supports OAM modes.High fidelity distribution of the entangled states is demonstrated by performing quantum state tomography in the polarization-OAM Hilbert space after fiber propagation and by violations of Bell inequalities and multipartite entanglement tests.The results open new scenarios for quantum applications where correlated complex states can be transmitted by exploiting the vectorial nature of light.
基金supported by the National Natural Science Foundation of China(No.11527804)Joint Research Fund in Astronomy under cooperative agreement between the National Natural Science Foundation of China(NSFC)and Chinese Academy of Sciences(CAS)(Nos.U1831115 and U1631239)+3 种基金Open Project of Key Laboratory of Astronomical Optics&Technology,Nanjing Institute of Astronomical Optics&Technology,Chinese Academy of Sciences(No.CAS-KLAOT-KF201806)Fundamental Research Funds for the Central Universities111 Project(No.B13015)the Harbin Engineering University.
文摘A novel phase-shifted long-period fiber grating(PS-LPFG)for the simultaneous measurement of torsion and temperature is described and experimentally demonstrated.The PS-LPFG is fabricated by inserting a pretwisted structure into the long-period fiber grating(LPFG)written in single-mode fiber(SMF).Experimental results show that the torsion sensitivities of the two dips are?0.114 nm/(rad/m)and?0.069 nm/(rad/m)in the clockwise direction,and?0.087 nm/(rad/m)and?0.048 nm/(rad/m)in the counterclockwise direction,respectively.The temperature sensitivities of the two dips are 0.057 nm/℃ and 0.051 nm/℃,respectively.The two dips of the PS-LPFG exhibit different responses to torsion and temperature.Simultaneous measurement of torsion and temperature can be implemented using a sensor.The feasibility and stabilization of simultaneous torsion and temperature measurement have been confirmed,and hence this novel PS-LPFG demonstrates potential for fiber sensing and engineering applications.
