The author considers the Feigenbaum's functional equation fP(λx) =λf(x) for each p ≥ 2.The existence of even unimodal C1 solutions to this equation is discussed and a feasible methodto construct such solutions ...The author considers the Feigenbaum's functional equation fP(λx) =λf(x) for each p ≥ 2.The existence of even unimodal C1 solutions to this equation is discussed and a feasible methodto construct such solutions is given.展开更多
We propose a novel scheme to generate the ultra-wideband (UWB) doublet signal pulse based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). In the scheme, only an optical source and an SOA...We propose a novel scheme to generate the ultra-wideband (UWB) doublet signal pulse based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). In the scheme, only an optical source and an SOA are needed. As there is only one wavelength included in the output doublet signal pulse, no time difference between the upper and down pulses is introduced during the transmission process. By using the software of Optisystem 7.0, the impacts of the optical power, the SOA current, the wavelength and the input signal pulse width on the generated doublet pulse are simulated and tudied numerically. The results show that when the pulse width of the input signal pulse is larger, the output signal pulse is better, and is insensitive to the change of wavelength. In addition, the ultra-wideband positive and negative monocycles can be generated by choosing suitable optical source power and SOA current.展开更多
文摘The author considers the Feigenbaum's functional equation fP(λx) =λf(x) for each p ≥ 2.The existence of even unimodal C1 solutions to this equation is discussed and a feasible methodto construct such solutions is given.
基金supported by the National Natural Science Foundation of China (No.60707006)the Natural Science Research Project of Jiangsu University (No.09KJB510009)the Scientific Research Foundation for Introducing Talent of Nanjing University of Posts & Telecom- munications (No.NY207142)
文摘We propose a novel scheme to generate the ultra-wideband (UWB) doublet signal pulse based on the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). In the scheme, only an optical source and an SOA are needed. As there is only one wavelength included in the output doublet signal pulse, no time difference between the upper and down pulses is introduced during the transmission process. By using the software of Optisystem 7.0, the impacts of the optical power, the SOA current, the wavelength and the input signal pulse width on the generated doublet pulse are simulated and tudied numerically. The results show that when the pulse width of the input signal pulse is larger, the output signal pulse is better, and is insensitive to the change of wavelength. In addition, the ultra-wideband positive and negative monocycles can be generated by choosing suitable optical source power and SOA current.
