We demonstrate a period poled tapered lithium niobate waveguide and study second harmonic generation(SHG)in this device for the purpose of broadening the quasi-phase matching(QPM)acceptance bandwidth.The finite-differ...We demonstrate a period poled tapered lithium niobate waveguide and study second harmonic generation(SHG)in this device for the purpose of broadening the quasi-phase matching(QPM)acceptance bandwidth.The finite-difference beam-propagation method is used to simulate the guided modes and calculate the effective indices.The simulation results show that by tapering the width of the cross section linearly,the phase mismatch between a specific input wavelength and its SHG signal can be varied along the propagation length.Ideal SHG phase-matching conditions for a wide range of input wavelengths in communication band from 1542.5 nm to 1553.5 nm can be satisfied in different positions of the waveguide.展开更多
We report rigorous coupled-wave analysis(RCWA) method to non-destructively characterize the domain structure of periodically poled lithium niobate(PPLN) crystal. The strong light diffraction effect is achieved by appl...We report rigorous coupled-wave analysis(RCWA) method to non-destructively characterize the domain structure of periodically poled lithium niobate(PPLN) crystal. The strong light diffraction effect is achieved by applying a proper external voltage. We can observe reversed domain pattern and employ the detected diffraction intensity to optimally fit the result of RCWA based on least square method. Compared with conventional scalar diffraction theory, more accurate domain structure parameters with accuracies of 0.05 μm and 0.005 for the period and duty cycle are obtained respectively. It is proved that accurate, real-time and nondestructive characterization can be realized via this method.展开更多
基金supported by the National Nature Science Foundation of China(No.51890862)。
文摘We demonstrate a period poled tapered lithium niobate waveguide and study second harmonic generation(SHG)in this device for the purpose of broadening the quasi-phase matching(QPM)acceptance bandwidth.The finite-difference beam-propagation method is used to simulate the guided modes and calculate the effective indices.The simulation results show that by tapering the width of the cross section linearly,the phase mismatch between a specific input wavelength and its SHG signal can be varied along the propagation length.Ideal SHG phase-matching conditions for a wide range of input wavelengths in communication band from 1542.5 nm to 1553.5 nm can be satisfied in different positions of the waveguide.
基金supported by the National High Technology Research and Development Program of China(No.2013AA030501)
文摘We report rigorous coupled-wave analysis(RCWA) method to non-destructively characterize the domain structure of periodically poled lithium niobate(PPLN) crystal. The strong light diffraction effect is achieved by applying a proper external voltage. We can observe reversed domain pattern and employ the detected diffraction intensity to optimally fit the result of RCWA based on least square method. Compared with conventional scalar diffraction theory, more accurate domain structure parameters with accuracies of 0.05 μm and 0.005 for the period and duty cycle are obtained respectively. It is proved that accurate, real-time and nondestructive characterization can be realized via this method.
