Large-scale and long-time molecular-dynamics simulations are used to investigate the temperature dependences of elastic properties for amorphous SiO2. The elastic moduli increase in a temperature range up to 1600 K an...Large-scale and long-time molecular-dynamics simulations are used to investigate the temperature dependences of elastic properties for amorphous SiO2. The elastic moduli increase in a temperature range up to 1600 K and decrease thereafter. The anomalous behaviour in elasticity is explained by analysing the changes of atomic-scale structure with respect to increment of temperature. The mechanism originates predominantly from distortion of the SiO4 tetrahedra network in low-temperature ranges. At an elevated temperature range, thermal-induced Si-O bond stretching dominates the process and leads to normal temperature dependence of elastic properties.展开更多
A novel scheme of all-optical clock recovery from mutiwavelength non-return-to-zero （NRZ） data stream is proposed and demonstrated. The chirp induced by a chirped fibre Bragg grating and a semiconductor optical ampl...A novel scheme of all-optical clock recovery from mutiwavelength non-return-to-zero （NRZ） data stream is proposed and demonstrated. The chirp induced by a chirped fibre Bragg grating and a semiconductor optical amplifier is used to enhance the clock. The clock is recovered after injecting the enhanced signal into the scheme based on the stimulated Brillouin scattering. The experiment is carried out and the dual-wavelength clock is recovered. This novel scheme can realize clock recovery of multiwavelength NRZ signal in the total wavelength range of 3.3nm. This clock recovery technology is transparent to the data bit rate and modulation format, also without pattern dependence.展开更多
A method for the optimal fiber input power determination is presented by employing the variation characteristics of signal to noise ratio(SNR) in spontaneous Brillouin-scattering-based sensing system. And a heterodyne...A method for the optimal fiber input power determination is presented by employing the variation characteristics of signal to noise ratio(SNR) in spontaneous Brillouin-scattering-based sensing system. And a heterodyne detection system is constructed for measuring the Brillouin scattering spectra with different fiber input powers. The Brillouin spectrum width and system SNR can be simultaneously measured from these spectra, and the optimal fiber input power can be obtained from such information. In the experiment, for 48.8-km-long standard single-mode fiber(SSMF), the optimal fiber input power values are all approximately 0 dBm obtained by the maximum SNR position for different local oscillator power values and average times.展开更多
基金Supported by the National Natural Science Foundation of China and the National Science Fund for Distinguished Young Scholars under Grant Nos 90403027 and 50772114.
文摘Large-scale and long-time molecular-dynamics simulations are used to investigate the temperature dependences of elastic properties for amorphous SiO2. The elastic moduli increase in a temperature range up to 1600 K and decrease thereafter. The anomalous behaviour in elasticity is explained by analysing the changes of atomic-scale structure with respect to increment of temperature. The mechanism originates predominantly from distortion of the SiO4 tetrahedra network in low-temperature ranges. At an elevated temperature range, thermal-induced Si-O bond stretching dominates the process and leads to normal temperature dependence of elastic properties.
基金Supported by the National Natural Science Foundation of China under Grant No 60437010.
文摘A novel scheme of all-optical clock recovery from mutiwavelength non-return-to-zero （NRZ） data stream is proposed and demonstrated. The chirp induced by a chirped fibre Bragg grating and a semiconductor optical amplifier is used to enhance the clock. The clock is recovered after injecting the enhanced signal into the scheme based on the stimulated Brillouin scattering. The experiment is carried out and the dual-wavelength clock is recovered. This novel scheme can realize clock recovery of multiwavelength NRZ signal in the total wavelength range of 3.3nm. This clock recovery technology is transparent to the data bit rate and modulation format, also without pattern dependence.
基金supported by the National Natural Science Foundation of China(No.61377088)the Natural Science Foundation of Hebei Province of China(Nos.E2015502053 and F2014502098)
文摘A method for the optimal fiber input power determination is presented by employing the variation characteristics of signal to noise ratio(SNR) in spontaneous Brillouin-scattering-based sensing system. And a heterodyne detection system is constructed for measuring the Brillouin scattering spectra with different fiber input powers. The Brillouin spectrum width and system SNR can be simultaneously measured from these spectra, and the optimal fiber input power can be obtained from such information. In the experiment, for 48.8-km-long standard single-mode fiber(SSMF), the optimal fiber input power values are all approximately 0 dBm obtained by the maximum SNR position for different local oscillator power values and average times.
