The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration va...The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration varies from 5SOps to 2.1 ns as a function o~ the increasing pump power. Correspondingly, the maximum pulse energy is 9.11 n3. Moreover, it is found that the wavelength tunable operation with a range of approximately 10 nm could be obtained by properly adjusting the polarization controllers. The characteristics of the rectangular pulses at different wavelengths are similar to each other. The demonstration of the wavelength tunable rectangular pulses would be beneficial to some applications for many fields such as spectroscopy and sensing research.展开更多
A novel ultrahigh-speed all-optical demultiplexer （DMUX） with polarization-shift-keying （PolSK） modula- tion input signals is proposed. This design is based on four-wave mixing （FWM） in a semiconductor optical a...A novel ultrahigh-speed all-optical demultiplexer （DMUX） with polarization-shift-keying （PolSK） modula- tion input signals is proposed. This design is based on four-wave mixing （FWM） in a semiconductor optical amplifier （SOA）. For analyzing each amplifier, we use finite-difference method （FDM） based on solution of the traveling wave coupled equations. Using numerical simulation, the all-optical DMUX is theoretically realized at 40 Gb/s. We also study the relation between optical confinement factor and thickness of active layer of the SOA section successfully, and investigate the increasing effect of confinement factor on the DMUX optical output power. With this work, the confinement factor is increased from 0.3 to 0.48, and as a result, the output power approximately twice of its initial value is achieved. Moreover, the effects of polarization dependence of SOA on the output performance of all-optical DMUX for PolSK signal are theoretically investigated in detail.展开更多
The synthesis of one-dimensional （1D） semiconductor nanostructures has been studied intensively for a wide range of materials due to their unique structural and physical properties and promising potential for future...The synthesis of one-dimensional （1D） semiconductor nanostructures has been studied intensively for a wide range of materials due to their unique structural and physical properties and promising potential for future technological applications. Among various strategies for synthesizing 1D semiconductor nanostructures, solution-phase synthetic routes are advantageous in terms of cost, throughput, modulation of composition, and the potential for large-scale and environmentally benign production. This article gives a concise review on the recent developments in the solution-phase synthesis of ID semiconductor nanostructures of different compositions, sizes, shapes, and architectures. We first introduce several typical solution-phase synthetic routes based on controlled precipitation from homogeneous solutions, including hydrothermal/solvothermal process, solution-liquid-solid （SLS） process, high-temperature organic-solution process, and low-temperature aqueous-solution process. Subsequently, we discuss two solution-phase synthetic strategies involving solid tem- plates or substrates, such as the chemical transformation of 1D sacrificial templates and the oriented growth of 1D nanostructure arrays on solid substrates. Finally, prospects of the solution-phase approaches to 1D semiconductor nanostructures will be briefly discussed.展开更多
Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. The...Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.展开更多
基金Supported by the National High-Technology Research and Development Program of China under Grant No 2014AA041901the NSAF Foundation of National Natural Science Foundation of China under Grant No U1330134+1 种基金the Opening Project of Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques under Grant No 2012ADL02the National Natural Science Foundation of China under Grant No 61308024
文摘The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration varies from 5SOps to 2.1 ns as a function o~ the increasing pump power. Correspondingly, the maximum pulse energy is 9.11 n3. Moreover, it is found that the wavelength tunable operation with a range of approximately 10 nm could be obtained by properly adjusting the polarization controllers. The characteristics of the rectangular pulses at different wavelengths are similar to each other. The demonstration of the wavelength tunable rectangular pulses would be beneficial to some applications for many fields such as spectroscopy and sensing research.
文摘A novel ultrahigh-speed all-optical demultiplexer （DMUX） with polarization-shift-keying （PolSK） modula- tion input signals is proposed. This design is based on four-wave mixing （FWM） in a semiconductor optical amplifier （SOA）. For analyzing each amplifier, we use finite-difference method （FDM） based on solution of the traveling wave coupled equations. Using numerical simulation, the all-optical DMUX is theoretically realized at 40 Gb/s. We also study the relation between optical confinement factor and thickness of active layer of the SOA section successfully, and investigate the increasing effect of confinement factor on the DMUX optical output power. With this work, the confinement factor is increased from 0.3 to 0.48, and as a result, the output power approximately twice of its initial value is achieved. Moreover, the effects of polarization dependence of SOA on the output performance of all-optical DMUX for PolSK signal are theoretically investigated in detail.
文摘The synthesis of one-dimensional （1D） semiconductor nanostructures has been studied intensively for a wide range of materials due to their unique structural and physical properties and promising potential for future technological applications. Among various strategies for synthesizing 1D semiconductor nanostructures, solution-phase synthetic routes are advantageous in terms of cost, throughput, modulation of composition, and the potential for large-scale and environmentally benign production. This article gives a concise review on the recent developments in the solution-phase synthesis of ID semiconductor nanostructures of different compositions, sizes, shapes, and architectures. We first introduce several typical solution-phase synthetic routes based on controlled precipitation from homogeneous solutions, including hydrothermal/solvothermal process, solution-liquid-solid （SLS） process, high-temperature organic-solution process, and low-temperature aqueous-solution process. Subsequently, we discuss two solution-phase synthetic strategies involving solid tem- plates or substrates, such as the chemical transformation of 1D sacrificial templates and the oriented growth of 1D nanostructure arrays on solid substrates. Finally, prospects of the solution-phase approaches to 1D semiconductor nanostructures will be briefly discussed.
基金Project supported by the National Natural Science Foundation of China(Nos.11672223,11402187,and 51178390)the China Postdoctoral Science Foundation(No.2014M560762)the Fundamental Research Funds for the Central Universities of China(No.xjj2015131)
文摘Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design.
