Journals >Chinese Optics Letters
Contents
2004
Volume: 2 Issue 11
19 Article(s)
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Fiber Optics and Optical Communications
High sensitivity fiber Bragg grating pressure difference sensor
Haiwei Fu, Junmei Fu, and Xueguang Qiao
Based on the effect of fiber Bragg grating (FBG) pressure difference sensitivity enhancement by encapsulating the FBG with uniform strength beam and metal bellows, a FBG pressure difference sensor is proposed, and its mechanism is also discussed. The relationship between Bragg wavelength and the pressure difference is Based on the effect of fiber Bragg grating (FBG) pressure difference sensitivity enhancement by encapsulating the FBG with uniform strength beam and metal bellows, a FBG pressure difference sensor is proposed, and its mechanism is also discussed. The relationship between Bragg wavelength and the pressure difference is derived, and the expression of the pressure difference sensitivity coefficient is also given. It is indicated that there is good linear relation between the Bragg wavelength shift and the pressure difference of the sensor. The theoretical and experimental pressure difference sensitivity coefficients are 38.67 and 37.6 nm/MPa, which are 12890 and 12533 times of that of the bare FBG, respectively. The pressure difference sensitivity and dynamic range can be easily changed by changing the size, Young's modulus, and Poisson's ratio of the beam and the bellows..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11621 (2004)
A 2 by 2 wavelength tunable Fabry-Perot filter by using an electro-optic polymer film
Xinwan Li, Ailun Ye, Jianping Chen, and Guiling Wu
A tunable Fabry-Perot (F-P) filter by using electro-optic polymer film is proposed. The electro-optic polymer is alkoxysilane dye (ASD)/SiO2-TiO2 hybrid material, whose electro-optic coefficient γ_(33) is about 5 pm/V. The wavelength tuning range of 3.8 nm under 400-V DC voltage and the nonlinear characteristic with thA tunable Fabry-Perot (F-P) filter by using electro-optic polymer film is proposed. The electro-optic polymer is alkoxysilane dye (ASD)/SiO2-TiO2 hybrid material, whose electro-optic coefficient γ_(33) is about 5 pm/V. The wavelength tuning range of 3.8 nm under 400-V DC voltage and the nonlinear characteristic with the electric field have been obtained via electro-optical properties of polymer. Both of polymer film fabrication and F-P filter designhave been introduced. The tunable F-P filter is designed for the application of two-input/two-output port wavelength-selective optical switch. Also, some problems have been discussed in this letter..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11624 (2004)
Study on forward stimulated Brillouin scattering in a backward pumped fiber Raman amplifier
Zaixuan Zhang, Laixiao Li, Dan Geng, Bizhi Dai, Yongxing Jin, Honglin Liu, Insoo S. Kim, Jianfeng Wang, Xiaobiao Wu, Dawei Fang, and Songlin Zhuang
Strong multi-order forward stimulated Brillouin scattering (SBS) has been observed in the backward pumped S-band distributed fiber Raman amplifier (FRA) with tunable narrow signal source (less than 100 MHz) when the pump power of FRA reached the SBS threshold. This does not obey the theory that only weak backward SBS lStrong multi-order forward stimulated Brillouin scattering (SBS) has been observed in the backward pumped S-band distributed fiber Raman amplifier (FRA) with tunable narrow signal source (less than 100 MHz) when the pump power of FRA reached the SBS threshold. This does not obey the theory that only weak backward SBS lines exist according to the conservation of energy and momentum and the wave vector selected rule. This is because the sound waveguide characteristic weakens the wave vector rule, and the forward transmitted sound waveguide Brillouin scattering lines are generated and amplified in FRA. When the pump power is further increased, 11 orders of SBS lines and comb-like profile are observed. For the excited line, the frequency is 197.2296 THz and the power is 0 dBm. The even order SBS lines are stronger than odd order SBS lines, the power of the 2nd and 4th order SBS lines is 1.75 dBm, which is 16 dB higher than that of the 1st and 3rd order SBS lines. The odd order SBS lines are named Brillouin-Rayleigh scattering lines..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11627 (2004)
Image Processing
Image watermarking capacity analysis based on Hopfield neural network
Fan Zhang, and Hongbin Zhang
In watermarking schemes, watermarking can be viewed as a form of communication problems. Almost all of previous works on image watermarking capacity are based on information theory, using Shannon formula to calculate the capacity of watermarking. In this paper, we present a blind watermarking algorithm using Hopfield nIn watermarking schemes, watermarking can be viewed as a form of communication problems. Almost all of previous works on image watermarking capacity are based on information theory, using Shannon formula to calculate the capacity of watermarking. In this paper, we present a blind watermarking algorithm using Hopfield neural network, and analyze watermarking capacity based on neural network. In our watermarking algorithm, watermarking capacity is decided by attraction basin of associative memory..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11634 (2004)
Approximating the CIECAM02 color appearance model by means of neural networks
Binghua Chai, Ningfang Liao, and Dazun Zhao
An artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now are widely used in calibration of digital camera, are chosen as samples to implement the forward and reverse color appearaAn artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now are widely used in calibration of digital camera, are chosen as samples to implement the forward and reverse color appearance models. When the predictive results are evaluated, for forward model, the output color appearance space is converted to the uniform color space based on CAM and is evaluated, while for reverse model, because the prediction precision is insufficient, we try to convert the color appearance space, which is the cylinder space, to the cube space similar to the red, green, and blue (RGB) space, and the results show that the precision is obviously improved..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11637 (2004)
Integrated Optics
Design of LICVD equipment for preparation of nano powder and study on laser threshold
Yingcai Liu, Yansheng Yin, Jing Li, and Gui Wang
A laser-induced chemical vapor deposition (LICVD) nanometer equipment is designed and fabricated. The design conception of key parts is expatiated. The energy threshold of SiH4 decomposing is studied. In the condition of same reactive gas flux, the laser energy threshold decreases with the increase of SiH4 concentratioA laser-induced chemical vapor deposition (LICVD) nanometer equipment is designed and fabricated. The design conception of key parts is expatiated. The energy threshold of SiH4 decomposing is studied. In the condition of same reactive gas flux, the laser energy threshold decreases with the increase of SiH4 concentration. In the condition of same SiH4 concentration, with the increase of reactive gas flux, the laser energy threshold which induces SiH4 decomposition increases linearly at the beginning, and when the flux is more than 100 ml/min, it turns to increase slowly. The factors which influence the laser threshold are analyzed..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11643 (2004)
Lasers and Laser Optics
High power AlGaInP laser diodes with zinc-diffused window mirror structure
Yun Xu, Qing Cao, Xiaopeng Zhu, Guohua Yang, Qiaoqiang Gan, Guofeng Song, Liang Guo, Yuzhang Li, and Lianghui Chen
The technology of zinc-diffusion to improve catastrophic optical damage (COD) threshold of compressively strained GaInP/AlGaInP quantum well laser diodes has been introduced. After zinc-diffusion, about 20-μm-long region at each facet of laser diode has been formed to serve as the window of the lasing light. As a resulThe technology of zinc-diffusion to improve catastrophic optical damage (COD) threshold of compressively strained GaInP/AlGaInP quantum well laser diodes has been introduced. After zinc-diffusion, about 20-μm-long region at each facet of laser diode has been formed to serve as the window of the lasing light. As a result, the COD threshold has been significantly improved due to the enlargement of bandgap by the zinc-diffusion induced quantum well intermixing, compared with that of the conventional non-window structure. 40-mW continuous wave output power with the fundamental transverse mode has been realized under room temperature for the 3.5-μm-wide ridge waveguide diode. The operation current is 84 mA and the slope efficiency is 0.74 W/A at 40 mW. The lasing wavelength is 656 nm..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11647 (2004)
Multi-use laser impulse pendulum and laser propulsion parameters measurement
Jing Li, Huifeng Tong, Jian Cai, Zhiping Tang, and Shengli Li
In order to investigate the mechanisms of both the air-breathing and the ablation modes of laser propulsion under laboratory conditions, a multi-use laser impulse pendulum (MULIP) is developed. The measurable impulse range is from 1.0*10^(-4) to 3.8*10^(-3) N.s. The experimental calibration data agree well with the theIn order to investigate the mechanisms of both the air-breathing and the ablation modes of laser propulsion under laboratory conditions, a multi-use laser impulse pendulum (MULIP) is developed. The measurable impulse range is from 1.0*10^(-4) to 3.8*10^(-3) N.s. The experimental calibration data agree well with the theoretical calculated data. With MULIP, the ablation mode has been performed, in which a high power pulsed Nd:glass laser (λ= 1.06 μm, τ= 20 ns) and a gray PVC film sample are used. The experimental results show that the maximum momentum coupling coefficient C_(m) is 7.73*10^(-5) N/W, and the maximum specific impulse I_(sp) is 208.6 s..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11650 (2004)
Research on film thickness of conductive line formed by laser micro-fine cladding and flexibly direct writing technique
Huiling Li, Xiaoyan Zeng, Huifen Li, Xiangyou Li, and Yiqun Chen
The conventional technology could not fulfill the rapidly growing need for fine conductive lines for its inherent limits. Therefore, in this study laser micro-fine cladding and flexibly direct writing technique is used to obtain conductive lines with high precision and reliability. In the case of different substrates aThe conventional technology could not fulfill the rapidly growing need for fine conductive lines for its inherent limits. Therefore, in this study laser micro-fine cladding and flexibly direct writing technique is used to obtain conductive lines with high precision and reliability. In the case of different substrates and parameters, film thickness will be different. Film thickness directly influences the reliability and stability of conductive lines with exception of quality and running speed. Therefore, we focus on developing the optimal parameters for the different substrates to achieve expected film thickness and make conductive lines have good performance and quality..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11654 (2004)
Soft X-ray amplification in 3- and 4-mm-diameter capillaries
Yuanli Cheng, Yongpeng Zhao, Qi Wang, Taniguch d, Y. Hayashi, and E. Hotta
Laser pulses with energy of ~10 μJ are generated at 46.9 nm on the 3p-3s transition of the Ne-like Ar by a fast capillary discharge setup in both 3- and 4-mm channels. The dependence of the laser output pulse energy on the pressure of Ar gas is measured for 3-mm-diameter capillaries at currents of 25, 30, and 35 kA. UnLaser pulses with energy of ~10 μJ are generated at 46.9 nm on the 3p-3s transition of the Ne-like Ar by a fast capillary discharge setup in both 3- and 4-mm channels. The dependence of the laser output pulse energy on the pressure of Ar gas is measured for 3-mm-diameter capillaries at currents of 25, 30, and 35 kA. Under the same discharge conditions used in 3-mm capillaries, experiments indicate that higher and faster current pulses are required to produce soft X-ray amplification in 4-mm-diamater capillaries..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11658 (2004)
Materials
Annealing effect on Cr,Yb:YAG laser crystal
Feng Wu, Zhiwei Zhao, Xiaodong Xu, Changtai Xia, Peizhen Deng, and Jun Xu
The absorption spectra, fluorescence spectra, and lifetimes of as-grown and annealed Cr,Yb:YAG crystal grown by Czochralski technique have been measured. The broad absorption bands in the visible region increase in intensity and shift to long wavelength after annealing, and the additional absorption around 482 nm may bThe absorption spectra, fluorescence spectra, and lifetimes of as-grown and annealed Cr,Yb:YAG crystal grown by Czochralski technique have been measured. The broad absorption bands in the visible region increase in intensity and shift to long wavelength after annealing, and the additional absorption around 482 nm may be possibly due to new octahedral Cr4+ center in the crystal, and the increase in the infrared (IR) region is due to the increase of Cr4+. The increase of Cr4+ also results in the groud state absorption and the concentration quenching of Yb3+ in Cr,Yb:YAG crystal after annealing, the fluorescence intensity is reduced to 75% and the emission lifetime is shortened from 1.40 to 0.44 ms..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11661 (2004)
Nonlinear Optics
Theoretical study of quasi-phase-matching fourth harmonic generation in periodically poled lithium tantalate
Wei Xie, Xianfeng Chen, Like He, Yuping Chen, and Yuxing Xia
The direct fourth harmonic generation (FHG) is theoretically demonstrated based on quasi-phase-matching (QPM) configuration in periodically poled lithium tantalate (PPLT). The wavelength dependence of the period of FHG QPM gratings is calculated. Bandwidths of fundamental wavelength, temperature, and incident angle areThe direct fourth harmonic generation (FHG) is theoretically demonstrated based on quasi-phase-matching (QPM) configuration in periodically poled lithium tantalate (PPLT). The wavelength dependence of the period of FHG QPM gratings is calculated. Bandwidths of fundamental wavelength, temperature, and incident angle are also studied. A very wide bandwidth, as large as 119.5 nm, of fundamental wavelength near 3699 nm is found with the QPM period of 9.442 μm and the crystal length of 1 cm..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11664 (2004)
Optical Devices
Harmonic beam splitter design and fabrication
Xiaofeng Ma, Yingjian Wang, Zhengxiu Fan, and Jianda Shao
Two problems of half-wave hole and high ripples in the transmittance region for a harmonic beam splitter had been pointed out and analyzed. Based on the application of a half-wavelength control and a new admittance matching methods, a harmonic beam splitter was designed and fabricated. The former method eliminated the Two problems of half-wave hole and high ripples in the transmittance region for a harmonic beam splitter had been pointed out and analyzed. Based on the application of a half-wavelength control and a new admittance matching methods, a harmonic beam splitter was designed and fabricated. The former method eliminated the half-wave hole fundamentally, and the latter smoothed high ripples in the transmittance region effectively. The matching stack consisted of a symmetrically periodic structure and provided a complete matching at the desired wavelength, i.e., both conditions for the equivalent admittance and phase thickness were fulfilled. Furthermore, both the theoretical and the tested curves had been given, and a good agreement between them was obtained..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11670 (2004)
Holography
Material optimization for low scattering noise during nonvolatile holographic recording in doubly doped LiNbO3 crystals
De'an Liu, Liren Liu, Liyong Ren, Zhu Luan, and Yu Zhou
Scattering noises in four kinds of lithium niobate crystals with the same double doping system, which are LiNbO3:Fe:Mn, LiNbO3:Ce:Mn, LiNbO3:Ce:Cu, and LiNbO3:Fe:Cu, are observed and compared experimentally. The results show that nonvolatile holographic recording can effectively suppress scattering noise, which mainly Scattering noises in four kinds of lithium niobate crystals with the same double doping system, which are LiNbO3:Fe:Mn, LiNbO3:Ce:Mn, LiNbO3:Ce:Cu, and LiNbO3:Fe:Cu, are observed and compared experimentally. The results show that nonvolatile holographic recording can effectively suppress scattering noise, which mainly depends on recombination coefficients of both the shallower centers and the deeper centers. The small recombination coefficients of the shallower centers and the large recombination coefficients of the deeper centers benefit the amplification of the signal gratings and the suppression of the noise gratings. In addition, the initial seed scattering also impacts the recorded scattering noise, and the little seed scattering results in low scattering noise. The theoretical simulations are performed for confirmation. Among the four kinds of doubly doped crystals, in LiNbO3:Ce:Cu the performances of nonvolatile recording are the best with low scattering noise and high diffraction efficiency..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11630 (2004)
Quantum Optics
Effects of phase fluctuation in an open four-level inversionless lasing system
Xijun Fan, Mengzheng Zhu, Zhengping Hong, Shangqing Gong, and Zhizhan Xu
A steady analytical solution of an open four-level inversionless lasing system with a driving field having the phase fluctuation has been given, and the effects of the finite width due to the phase fluctuation on the gain, dispersion, and population difference have been analyzed by using the numerical simulation from tA steady analytical solution of an open four-level inversionless lasing system with a driving field having the phase fluctuation has been given, and the effects of the finite width due to the phase fluctuation on the gain, dispersion, and population difference have been analyzed by using the numerical simulation from the steady analytical solution. It is found that: with the linewidth increasing, the gain decreases and the absolute value of population difference between levels coupled by the probe field increases, but the variation of the linewidth cannot change the properties of the inversionless lasing and refractive index increase of the system; when the linewidth does not equal to zero, the system can still get a high refractive index with zero absorption, and these conclusions have very obvious difference from those obtained in other inversionless lasing systems..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11673 (2004)
Instrumentation, Measurement, and Metrology
Digital measuring scheme for half-wave voltage of Y-tap multiple integrated optical circuit
Yuanhong Yang, and Hongtao Yu
A high-precision digital measuring scheme for half-wave voltage of Y-tap multiple integrated optical circuits is proposed. This scheme is based on Sagnac interferometer modulated with digital step waveform whose frequency is half of eigen frequency of the interferometer. The technology and measuring precision are discuA high-precision digital measuring scheme for half-wave voltage of Y-tap multiple integrated optical circuits is proposed. This scheme is based on Sagnac interferometer modulated with digital step waveform whose frequency is half of eigen frequency of the interferometer. The technology and measuring precision are discussed. An experimental setup is made and the temperature-dependences of half-wave voltage of two samples are studied. Analysis and experimental study prove that this scheme is convenient and accurate..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11640 (2004)
Ultrafast Optics
Experimental study on terahertz radiation
Liying Lang, Qirong Xing, Shuxin Li, Fanglin Mao, Lu Chai, and Qingyue Wang
In this letter, we describe a coherent subpicosecond terahertz (THz) spectroscopy system based on non-resonant optical rectification for the generation of THz radiation. We studied the two-photon absorption (TPA) of ZnTe induced by femtosecond laser pulses via THz generation, and its influence on the generation of THz In this letter, we describe a coherent subpicosecond terahertz (THz) spectroscopy system based on non-resonant optical rectification for the generation of THz radiation. We studied the two-photon absorption (TPA) of ZnTe induced by femtosecond laser pulses via THz generation, and its influence on the generation of THz radiation. Experimental results demonstrated that the intensity of pump beam against TPA must be traded off to get an optimum generation of THz radiation. As an example, we measured absorption spectrum of water vapor by time-domain spectroscopy (TDS) in the frequency range from 0.5 to 2.5 THz with a high overall accuracy..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11677 (2004)
X-Ray Optics
Optimization of constant-length Rowland-circle monochromator with a varied line-spacing grating
Lijun Lu
We use a varied line-spacing (VLS) grating to improve the performances of the constant-length Rowland-circle spherical grating monochromator. The translation distance of the mirror-grating tank in a scan of certain wavelength range will get much shorter. This will make the instrument easier to realize. Based on the priWe use a varied line-spacing (VLS) grating to improve the performances of the constant-length Rowland-circle spherical grating monochromator. The translation distance of the mirror-grating tank in a scan of certain wavelength range will get much shorter. This will make the instrument easier to realize. Based on the principle of monochromator, we study how to optimize the optical system with a VLS grating in detail. The main imaging performances of the instrument are also evaluated..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11680 (2004)
Optical Computing
A scheme of optical interconnection for super high speed parallel computer
Youju Mao, Yi Lv, Jiang Liu, and Mingrui Dang
An optical cross connection network which adopts coarse wavelength division multiplexing (CWDM) and data packet is introduced. It can be used to realize communication between multi-CPU and multi-MEM in parallel computing system. It provides an effective way to upgrade the capability of parallel computer by combining opAn optical cross connection network which adopts coarse wavelength division multiplexing (CWDM) and data packet is introduced. It can be used to realize communication between multi-CPU and multi-MEM in parallel computing system. It provides an effective way to upgrade the capability of parallel computer by combining optical wavelength division multiplexing (WDM) and data packet switching technology. CWDM used in network construction, optical cross connection (OXC) based on optical switch arrays, and data packet format used in network construction were analyzed. We have also done the optimizing analysis of the number of optical switches needed in different scales of network in this paper. The architecture of the optical interconnection for 8 wavelength channels and 128 bits parallel transmission has been researched. Finally, a parallel transmission system with 4 nodes, 8 channels per node, has been designed..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 11, 11667 (2004)
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