We investigate the self-tapping phenomena for two weakly coupled Bose-Einstein condensates with a rapid periodic modulation of the atomic scattering length. By using an averaging method, the equations of motion of the...We investigate the self-tapping phenomena for two weakly coupled Bose-Einstein condensates with a rapid periodic modulation of the atomic scattering length. By using an averaging method, the equations of motion of the slow dynamics are derived to analyze the self-trapping behavior. It is shown numerically that under certain conditions, an alternative self-trapping in either well appears.展开更多
The propagation of femtosecond laser pulses with wavelengths of 1550 nm, 1064 nm, 800 nm and 700 nm, respectively, which are in the normal dispersion region of the nano-structured photonic crystal fiber (N-PCF) with i...The propagation of femtosecond laser pulses with wavelengths of 1550 nm, 1064 nm, 800 nm and 700 nm, respectively, which are in the normal dispersion region of the nano-structured photonic crystal fiber (N-PCF) with interesting broadband normal dispersion and highly nonlinear properties, is studied. For the effect of chirp variation mainly induced by group velocity dispersion (GVD) and self-phase modulation (SPM), after propagation over a short length, the wave breaking occurs. Namely, oscillatory structures are presented near pulse edges and sidelobes appear in the pulse spectrum. In the case of 800 nm, after the propagation of 20 mm, a super flat spectrum is obtained. The bandwidth of the super flat spectrum is associated with the dispersion length and the nonlinear length. By choosing N-PCF and laser pulse with appropriate parameters, a broadband super flat spectrum in a short length can be achieved.展开更多
The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system （RDTS） is analyzed in detail, and a simple correction algorithm is proposed to compensate the...The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system （RDTS） is analyzed in detail, and a simple correction algorithm is proposed to compensate the fiber position error caused by the wavelength dispersion. The principle of the proposed algorithm is described theoretically, and the correction on each point along the entire fiber is realized. Temperature simulation results validate that the temperature distortion is corrected and the temperature accuracy is effectively improved from ＋5 ℃ to ±1 ℃.展开更多
In this paper,the optimum supercontinuum(SC)spectrum generation in a dispersion decreasing fiber is presented.Three normalized parameters for the pump pulse and SC fiber are introduced.It is found that the shape of an...In this paper,the optimum supercontinuum(SC)spectrum generation in a dispersion decreasing fiber is presented.Three normalized parameters for the pump pulse and SC fiber are introduced.It is found that the shape of an SC spectrum is uniquely specified by the input soliton order,the normalized dispersion slope and the normalized effective fiber length.For a pumping condition with a given input soliton order and a given normalized dispersion slope,by optimizing the normalized effective fiber length,the residual spectral peak in the SC spectrum can be suppressed effectively,and a broad SC spectrum with optimum spectral flatness can be obtained.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos.10847123,10575034,and 10875039
文摘We investigate the self-tapping phenomena for two weakly coupled Bose-Einstein condensates with a rapid periodic modulation of the atomic scattering length. By using an averaging method, the equations of motion of the slow dynamics are derived to analyze the self-trapping behavior. It is shown numerically that under certain conditions, an alternative self-trapping in either well appears.
基金supported by the National Natural Science Foundation of China (No. 10874145)the China Postdoctoral Science Foundation(Nos. 20080440014 and 200902046)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20091333110010)the Natural Science Foundation of Hebei Province (No. F2009000481)
文摘The propagation of femtosecond laser pulses with wavelengths of 1550 nm, 1064 nm, 800 nm and 700 nm, respectively, which are in the normal dispersion region of the nano-structured photonic crystal fiber (N-PCF) with interesting broadband normal dispersion and highly nonlinear properties, is studied. For the effect of chirp variation mainly induced by group velocity dispersion (GVD) and self-phase modulation (SPM), after propagation over a short length, the wave breaking occurs. Namely, oscillatory structures are presented near pulse edges and sidelobes appear in the pulse spectrum. In the case of 800 nm, after the propagation of 20 mm, a super flat spectrum is obtained. The bandwidth of the super flat spectrum is associated with the dispersion length and the nonlinear length. By choosing N-PCF and laser pulse with appropriate parameters, a broadband super flat spectrum in a short length can be achieved.
基金This work was supported by Natural Science Foundation of China （60977058）, Science Fund for Distinguished Young Scholars of Shandong Province of China （JQ200819）, Independent Innovation Foundation of Shandong University （IIFSDU2010JC002＆2012JC015）, and promotive research fund for excellent young and middle-aged scientists of Shandong Province （BS2010DX028）.
文摘The influence of the wavelength dispersion on the temperature accuracy of the Raman distributed temperature sensor system （RDTS） is analyzed in detail, and a simple correction algorithm is proposed to compensate the fiber position error caused by the wavelength dispersion. The principle of the proposed algorithm is described theoretically, and the correction on each point along the entire fiber is realized. Temperature simulation results validate that the temperature distortion is corrected and the temperature accuracy is effectively improved from ＋5 ℃ to ±1 ℃.
基金supported by the Guangdong Natural Science Fund(No.1414050001224)the National Instrumentation Program(No.2012YQ14000511)the Guangdong Science and Technology Program(No.2012B090600009)
文摘In this paper,the optimum supercontinuum(SC)spectrum generation in a dispersion decreasing fiber is presented.Three normalized parameters for the pump pulse and SC fiber are introduced.It is found that the shape of an SC spectrum is uniquely specified by the input soliton order,the normalized dispersion slope and the normalized effective fiber length.For a pumping condition with a given input soliton order and a given normalized dispersion slope,by optimizing the normalized effective fiber length,the residual spectral peak in the SC spectrum can be suppressed effectively,and a broad SC spectrum with optimum spectral flatness can be obtained.
