The optimization of the fiber-coupled terahertz time-domain spectroscopy（THz-TDS） system is performed by changing the polarization of the optical excitation pulse centered at 1550 nm. In Ga As/In Al As multilayer st...The optimization of the fiber-coupled terahertz time-domain spectroscopy（THz-TDS） system is performed by changing the polarization of the optical excitation pulse centered at 1550 nm. In Ga As/In Al As multilayer structures based photoconductive antennas are used in TDS setup as both the emitter and receiver. The experimental results demonstrate that not only the THz signal power but also the temporal waveform vary with the rotation of the exciting pulse polarization. Maximum output power of the emitter is obtained when the polarization of the pump pulse is perpendicular to the edge of the metal electrodes. At this moment the THz waveform is close to a single-cycled pulse. However, double THz pulses could be recorded when the pump laser polarization is parallel to the electrodes. Laser pulse splitting induced by the birefringence of the optical fiber may attribute to the polarizationdependent performance of the fiber-coupled THz-TDS system.展开更多
The effect of third order dispersion on pulse transmission is discussed. The coupled nonlinear Schrdinger equations characterizing the birefringent single mode fibers is solved numerically with combined consideratio...The effect of third order dispersion on pulse transmission is discussed. The coupled nonlinear Schrdinger equations characterizing the birefringent single mode fibers is solved numerically with combined consideration on chromatic dispersion, including second and third order dispersions, polarization mode dispersion (PMD) and nonlinearity. Various simulation results are presented.展开更多
Theoretically and experimentally, the effects of temperature on the weak principal axis of twisted optical fiber loop are analyzed, and the results show that the location of the pair of weak principal axis will drift ...Theoretically and experimentally, the effects of temperature on the weak principal axis of twisted optical fiber loop are analyzed, and the results show that the location of the pair of weak principal axis will drift with temperature change, which will deteriorate the stability of system when applied to sensor system. In this paper, the influence of phase drift of weak principal axis on the performance of optical fiber current sensor is mainly predicted theoretically. Our research results will provide a beneficial reference for improving optical fiber sensor system.展开更多
Previous studies on modulation instabilities（MIs） in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fib...Previous studies on modulation instabilities（MIs） in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fibers with the emphasis on investigating the effects of ellipticity angle（0？ ≤θ≤ 90？）. Both symmetric and antisymmetric CW states are considered. In the anomalous dispersion regime, for the symmetric（antisymmetric） CW states, we show that MI gain increases dramatically（reduces first and then enhances greatly） as the increment of θ. In the normal dispersion regime, for the both CW states, the distinctive feature is that the gain of the MI bands reduces first, vanishes at θ = 45？,reappears across this ellipticity angle, and quickly increases after then.展开更多
In this paper, we report a novel method for accurately measuring the photo-induced birefringence of photosensitive fiber by using Mach-Zehnder interferometer. The results indicate that the normalized birefringence can...In this paper, we report a novel method for accurately measuring the photo-induced birefringence of photosensitive fiber by using Mach-Zehnder interferometer. The results indicate that the normalized birefringence can attain 10-5.展开更多
In this manuscript,we discuss the dynamical behavior of Chen-Lee-Liu(CLL)equation in birefringent fibers which is modeled by two-component nonlinear Schrodinger equation(NLSE)without four-wave mixing effect.In optical...In this manuscript,we discuss the dynamical behavior of Chen-Lee-Liu(CLL)equation in birefringent fibers which is modeled by two-component nonlinear Schrodinger equation(NLSE)without four-wave mixing effect.In optical fibers and other wave-guide mediums this system models the propagation of soliton flow using group velocity dispersion(GVD)and self-steeping coefficients.In the realms of maritime transport,motion,and energy,the dynamics of deep-sea waves is one of oceanography’s greatest challenges.A mathematical model of the dynamics of solitary waves in the deep ocean under a twolayer stratification yields the NLSE,and resultantly,the interaction between the two can be described by a coupled NLSE.Using two recently developed integration tools,namely the generalized exponential rational function method(GERFM)and the new extended direct algebraic method(NEDAM),the various optical pulses in the forms of bright,dark,combined,and complex solitons are extracted.Moreover,the hyperbolic,exponential,and trigonometric function solutions are recovered.In addition,a comparison is made between our results and those that are well-known,and the study concludes that the solutions we’ve reached are novel.By choosing appropriate parameter values for numerical simulation and physical explanations,the significance of the results is demonstrated.The results of this paper can enhance the nonlinear dynamical behavior of a given system and demonstrate the suitability of the methodology em-ployed.This research,in our opinion,will be beneficial to a wide variety of engineering model specialists.展开更多
The purpose of this work is to study the nonlinear propagation of coupled pulses within birefringent optical fibers.To achieve this,an effective analytical technique using iB-function was applied.With this approach,we...The purpose of this work is to study the nonlinear propagation of coupled pulses within birefringent optical fibers.To achieve this,an effective analytical technique using iB-function was applied.With this approach,we decoupled the nonlinear partial differential equations governing the wave propagation and solved them to obtain prototype solutions likely to propagate in the medium.A Mathlab program was then developed to validate the behavior of the propagated waves and analyze the resulting curves.The results revealed distinct complex phenomena such as stable propagation of coupled dark-bright vector soliton,energy exchange between the components during propagation to severe pulse broadening and conditions leading to group velocity walk-off.These findings provided a deeper insight into light propagation,improving its application for advanced optical communication systems and fiber-based devices.展开更多
A strain-induced birefringence double-clad (DC) fiber Bragg grating (FBG) is proposed and demonstrated. The grating is fabricated in the core of rectangular inner cladding double clad fiber by using phase mask method....A strain-induced birefringence double-clad (DC) fiber Bragg grating (FBG) is proposed and demonstrated. The grating is fabricated in the core of rectangular inner cladding double clad fiber by using phase mask method. By applying lateral strain on the grating, the birefringence is induced. In order to detect the birefringent effect of the grating, we use it as the output mirror of a laser. When lateral strain is applied, the grating becomes birefringent. Therefore, one reflection peak of double-clad fiber Bragg grating becomes two peaks and the laser also lases in two wavelengths. The wavelength spacing of the laser can be tuned from 0 to 0.8 nm. The absolute wavelengths for the two polarizations can be tuned 1.2 and 2.0 nm, respectively.展开更多
This paper studies the generation of the dispersive wave(DW)in the normal dispersion regimes of the birefringent photonic crystal fiber(BPCF)fabricated in this work.The remarkable blue-shifted radiation is found to be...This paper studies the generation of the dispersive wave(DW)in the normal dispersion regimes of the birefringent photonic crystal fiber(BPCF)fabricated in this work.The remarkable blue-shifted radiation is found to be generated when 30 fs pulses are input in the normal dispersion regime of the BPCF for the first time.The characteristics of the blue-shifted DW strongly depend on the polarization of the input pulse.As a result,two peaks appear in the blue-shifted region of the spectrum when the input pulses polarize along the slow axis of the BPCF.With the increase of the center wavelength of the initial input pulse,the difference between the wavelengths of the two peaks widens.The peak location in the spectrum can be explained by the phase matching condition between the DW and the input pulse.In addition,when the input polarization is set to an angle of 45°with respect to the principal axes of the BPCF,the cross-phase modulation and coherent coupling between two orthogonally polarized modes would result in pulse trapping in the BPCF.Accordingly,the DW shift toward short wavelength is restrained.The DW generation in the normal-dispersion regimes of BPCF can be controlled by the phase matching condition and polarization of the input pulse.展开更多
基金supported by National Basic Research Program of China under Grant No.2014CB339802,No.2011CB808100National Natural Science Foundation of China under Grant No.11174156
文摘The optimization of the fiber-coupled terahertz time-domain spectroscopy（THz-TDS） system is performed by changing the polarization of the optical excitation pulse centered at 1550 nm. In Ga As/In Al As multilayer structures based photoconductive antennas are used in TDS setup as both the emitter and receiver. The experimental results demonstrate that not only the THz signal power but also the temporal waveform vary with the rotation of the exciting pulse polarization. Maximum output power of the emitter is obtained when the polarization of the pump pulse is perpendicular to the edge of the metal electrodes. At this moment the THz waveform is close to a single-cycled pulse. However, double THz pulses could be recorded when the pump laser polarization is parallel to the electrodes. Laser pulse splitting induced by the birefringence of the optical fiber may attribute to the polarizationdependent performance of the fiber-coupled THz-TDS system.
文摘The effect of third order dispersion on pulse transmission is discussed. The coupled nonlinear Schrdinger equations characterizing the birefringent single mode fibers is solved numerically with combined consideration on chromatic dispersion, including second and third order dispersions, polarization mode dispersion (PMD) and nonlinearity. Various simulation results are presented.
文摘Theoretically and experimentally, the effects of temperature on the weak principal axis of twisted optical fiber loop are analyzed, and the results show that the location of the pair of weak principal axis will drift with temperature change, which will deteriorate the stability of system when applied to sensor system. In this paper, the influence of phase drift of weak principal axis on the performance of optical fiber current sensor is mainly predicted theoretically. Our research results will provide a beneficial reference for improving optical fiber sensor system.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11447113 and 11305031 Natural Science Foundation of Jiangsu Provincial Universities under Grant No.14KJB140009 the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology under Grant No.2241131301064
文摘Previous studies on modulation instabilities（MIs） in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fibers with the emphasis on investigating the effects of ellipticity angle（0？ ≤θ≤ 90？）. Both symmetric and antisymmetric CW states are considered. In the anomalous dispersion regime, for the symmetric（antisymmetric） CW states, we show that MI gain increases dramatically（reduces first and then enhances greatly） as the increment of θ. In the normal dispersion regime, for the both CW states, the distinctive feature is that the gain of the MI bands reduces first, vanishes at θ = 45？,reappears across this ellipticity angle, and quickly increases after then.
基金Supported by the National "863" high technology project(2002AA313110)
文摘In this paper, we report a novel method for accurately measuring the photo-induced birefringence of photosensitive fiber by using Mach-Zehnder interferometer. The results indicate that the normalized birefringence can attain 10-5.
基金the financial support provided for this research via the National Natural Science Foun-dation of China(52071298)。
文摘In this manuscript,we discuss the dynamical behavior of Chen-Lee-Liu(CLL)equation in birefringent fibers which is modeled by two-component nonlinear Schrodinger equation(NLSE)without four-wave mixing effect.In optical fibers and other wave-guide mediums this system models the propagation of soliton flow using group velocity dispersion(GVD)and self-steeping coefficients.In the realms of maritime transport,motion,and energy,the dynamics of deep-sea waves is one of oceanography’s greatest challenges.A mathematical model of the dynamics of solitary waves in the deep ocean under a twolayer stratification yields the NLSE,and resultantly,the interaction between the two can be described by a coupled NLSE.Using two recently developed integration tools,namely the generalized exponential rational function method(GERFM)and the new extended direct algebraic method(NEDAM),the various optical pulses in the forms of bright,dark,combined,and complex solitons are extracted.Moreover,the hyperbolic,exponential,and trigonometric function solutions are recovered.In addition,a comparison is made between our results and those that are well-known,and the study concludes that the solutions we’ve reached are novel.By choosing appropriate parameter values for numerical simulation and physical explanations,the significance of the results is demonstrated.The results of this paper can enhance the nonlinear dynamical behavior of a given system and demonstrate the suitability of the methodology em-ployed.This research,in our opinion,will be beneficial to a wide variety of engineering model specialists.
文摘The purpose of this work is to study the nonlinear propagation of coupled pulses within birefringent optical fibers.To achieve this,an effective analytical technique using iB-function was applied.With this approach,we decoupled the nonlinear partial differential equations governing the wave propagation and solved them to obtain prototype solutions likely to propagate in the medium.A Mathlab program was then developed to validate the behavior of the propagated waves and analyze the resulting curves.The results revealed distinct complex phenomena such as stable propagation of coupled dark-bright vector soliton,energy exchange between the components during propagation to severe pulse broadening and conditions leading to group velocity walk-off.These findings provided a deeper insight into light propagation,improving its application for advanced optical communication systems and fiber-based devices.
基金This work was supported by the National Natural Science Foundation of China (No. 60137010) the National '863' Project of China (No. 2003AA312100).
文摘A strain-induced birefringence double-clad (DC) fiber Bragg grating (FBG) is proposed and demonstrated. The grating is fabricated in the core of rectangular inner cladding double clad fiber by using phase mask method. By applying lateral strain on the grating, the birefringence is induced. In order to detect the birefringent effect of the grating, we use it as the output mirror of a laser. When lateral strain is applied, the grating becomes birefringent. Therefore, one reflection peak of double-clad fiber Bragg grating becomes two peaks and the laser also lases in two wavelengths. The wavelength spacing of the laser can be tuned from 0 to 0.8 nm. The absolute wavelengths for the two polarizations can be tuned 1.2 and 2.0 nm, respectively.
基金supported in part by the National Natural Science Founda-tion of China(Grant No.10874145)Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20091333110010)+1 种基金the Nature Science Foundation of Hebei Province(Grant No.F2009000481)the China Postdoctoral Science Foundation(Grant Nos.20080440014 and 200902046)
文摘This paper studies the generation of the dispersive wave(DW)in the normal dispersion regimes of the birefringent photonic crystal fiber(BPCF)fabricated in this work.The remarkable blue-shifted radiation is found to be generated when 30 fs pulses are input in the normal dispersion regime of the BPCF for the first time.The characteristics of the blue-shifted DW strongly depend on the polarization of the input pulse.As a result,two peaks appear in the blue-shifted region of the spectrum when the input pulses polarize along the slow axis of the BPCF.With the increase of the center wavelength of the initial input pulse,the difference between the wavelengths of the two peaks widens.The peak location in the spectrum can be explained by the phase matching condition between the DW and the input pulse.In addition,when the input polarization is set to an angle of 45°with respect to the principal axes of the BPCF,the cross-phase modulation and coherent coupling between two orthogonally polarized modes would result in pulse trapping in the BPCF.Accordingly,the DW shift toward short wavelength is restrained.The DW generation in the normal-dispersion regimes of BPCF can be controlled by the phase matching condition and polarization of the input pulse.
