The structure of a strip LiNbO3 waveguide clad with a planar LiNbOa waveguide is proposed to fabricate a long-period waveguide grating （LPWG）. It is shown theoretically that an LPWG device based on such a special Li...The structure of a strip LiNbO3 waveguide clad with a planar LiNbOa waveguide is proposed to fabricate a long-period waveguide grating （LPWG）. It is shown theoretically that an LPWG device based on such a special LiNbOa waveguide structure is of the merit of thermal stability. The methods for fabrication of planar waveguide, channel waveguide and grating are suggested and discussed. Detailed design consideration is exemplified based on a soft-proton-exchange planar waveguide clad Ti-diffused LiNbOa （Z-cut） strip waveguide.展开更多
In order to minimize the effect of the unconsidered frequency components on the generated compression pulse, the phasing-blanking effect is taken into account of designing the one^dimensionai aperiodic domain reversal...In order to minimize the effect of the unconsidered frequency components on the generated compression pulse, the phasing-blanking effect is taken into account of designing the one^dimensionai aperiodic domain reversal structure. Hierarchic genetic algorithm for the design of a domain reversal grating to modulate the spectrum and phase of the generated SH pulse simultaneously are presented. Our simulation shows that the quality of an output pulse is fairly improved.展开更多
We report the single-to-multiple channel wavelength conversions of 1.57-ps pulses based on cascaded secondharmonic generation and difference frequency generation in quasi-phase-matched periodically poled lithium hieba...We report the single-to-multiple channel wavelength conversions of 1.57-ps pulses based on cascaded secondharmonic generation and difference frequency generation in quasi-phase-matched periodically poled lithium hiebate waveguides. For single-to-single channel wavelength conversion, no external cavity laser is required with use of a fibre ring laser. The conversion efficiency is about -21.44 dB. The converted idler wavelength can be tuned from 1526.4nm to 1537.5nm as the lasing pump wavelength is varied from 1566.1 nm to 1555.0nm. By employing several input pumps, tunable single-to-dual and single-to-triple channel wavelength conversions are experimentally demonstrated.展开更多
Three wavelengths of red, green and blue of recording beams are systemically tested for the UV-assistant recording and optical fixing of holograms in a strongly oxidized Ce：Cu：LiNbO3 crystal. Three different photore...Three wavelengths of red, green and blue of recording beams are systemically tested for the UV-assistant recording and optical fixing of holograms in a strongly oxidized Ce：Cu：LiNbO3 crystal. Three different photorefractive phenomena are observed. It is shown that the green beams will optimally generate a critical strong nonvolatile hologram with quick sensitivity and the optimal switching technique could be jointly used to obtain a nearly 100% high diffraction. Theoretical verification is given, and a prescription on the doping densities and on the oxidation/reduction states of the material to match a defined recording wavelength for high diffraction is suggested.展开更多
The optical erasure dynamics in a batch-thermal fixing scheme of holographic storage in photorefractive crystals is investigated theoretically and experimentally. The inter-batch optical erasure time constant τF is i...The optical erasure dynamics in a batch-thermal fixing scheme of holographic storage in photorefractive crystals is investigated theoretically and experimentally. The inter-batch optical erasure time constant τF is introduced to specify the optical erasure to compensated gratings, and measured in a sophisticated experiment. The experimental result shows that τF is much longer than the intra-batch optical erasure time constant τE. The difference between τFand τE is fundamental for enhancing nonvolatile storage density.展开更多
文摘The structure of a strip LiNbO3 waveguide clad with a planar LiNbOa waveguide is proposed to fabricate a long-period waveguide grating （LPWG）. It is shown theoretically that an LPWG device based on such a special LiNbOa waveguide structure is of the merit of thermal stability. The methods for fabrication of planar waveguide, channel waveguide and grating are suggested and discussed. Detailed design consideration is exemplified based on a soft-proton-exchange planar waveguide clad Ti-diffused LiNbOa （Z-cut） strip waveguide.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60477016 and 10574092, the National Basic Research Programme of China under Grant No 2006CB806000.
文摘In order to minimize the effect of the unconsidered frequency components on the generated compression pulse, the phasing-blanking effect is taken into account of designing the one^dimensionai aperiodic domain reversal structure. Hierarchic genetic algorithm for the design of a domain reversal grating to modulate the spectrum and phase of the generated SH pulse simultaneously are presented. Our simulation shows that the quality of an output pulse is fairly improved.
基金Supported by the National Natural Science Foundation of China under Grant No 60577006.
文摘We report the single-to-multiple channel wavelength conversions of 1.57-ps pulses based on cascaded secondharmonic generation and difference frequency generation in quasi-phase-matched periodically poled lithium hiebate waveguides. For single-to-single channel wavelength conversion, no external cavity laser is required with use of a fibre ring laser. The conversion efficiency is about -21.44 dB. The converted idler wavelength can be tuned from 1526.4nm to 1537.5nm as the lasing pump wavelength is varied from 1566.1 nm to 1555.0nm. By employing several input pumps, tunable single-to-dual and single-to-triple channel wavelength conversions are experimentally demonstrated.
文摘Three wavelengths of red, green and blue of recording beams are systemically tested for the UV-assistant recording and optical fixing of holograms in a strongly oxidized Ce：Cu：LiNbO3 crystal. Three different photorefractive phenomena are observed. It is shown that the green beams will optimally generate a critical strong nonvolatile hologram with quick sensitivity and the optimal switching technique could be jointly used to obtain a nearly 100% high diffraction. Theoretical verification is given, and a prescription on the doping densities and on the oxidation/reduction states of the material to match a defined recording wavelength for high diffraction is suggested.
基金Supported by the National Key Basic Research Special Foundation of China under Grant No G19990330, and the National Natural Science Foundation of China under Grant No 60377003.
文摘The optical erasure dynamics in a batch-thermal fixing scheme of holographic storage in photorefractive crystals is investigated theoretically and experimentally. The inter-batch optical erasure time constant τF is introduced to specify the optical erasure to compensated gratings, and measured in a sophisticated experiment. The experimental result shows that τF is much longer than the intra-batch optical erasure time constant τE. The difference between τFand τE is fundamental for enhancing nonvolatile storage density.
