Journals >Chinese Optics Letters
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2004
Volume: 2 Issue 3
21 Article(s)
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Fiber Optics and Optical Communications
Simulation analysis of one-stage C+L-band erbium-doped fiber ASE source with double-pass bi-directional pumping configuration
Wencai Huang, and Hai Ming
A new technique to generate a C+L-band flat amplified spontaneous emission (ASE) source in one-stage erbium-doped fiber (EDF) using bi-directional pumping configuration is analyzed. The simulation results show that the key point of obtaining flat C+L-band ASE spectrum in one-stage EDF is using a laser diode operated atA new technique to generate a C+L-band flat amplified spontaneous emission (ASE) source in one-stage erbium-doped fiber (EDF) using bi-directional pumping configuration is analyzed. The simulation results show that the key point of obtaining flat C+L-band ASE spectrum in one-stage EDF is using a laser diode operated at 980 nm as backward pump source. ASE source with nearly 80-nm bandwidth can be obtained by means of selecting suitable fiber length and properly adjusting the ratio of forward to backward pump power..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03125 (2004)
A novel modulation and direct detection scheme of optical phase shift keying
Yongcai Yang, and Wolfgang Vogel
This paper introduces a new modulation and direct detection scheme of optical phase shift keying (PSK) which is simple and practical in fiber optical communication. A phase modulator is used to modulate a continuous wave (CW) laser source and return-to-zero (RZ) signal that is changed from the initial transmitting infoThis paper introduces a new modulation and direct detection scheme of optical phase shift keying (PSK) which is simple and practical in fiber optical communication. A phase modulator is used to modulate a continuous wave (CW) laser source and return-to-zero (RZ) signal that is changed from the initial transmitting information is used to control a phase modulator to form a optical PSK signal. In the receiver terminal, just add a signal delayed a half of one bit to itself so that the initial information can be restored..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03128 (2004)
Effects of the switching time in OPS/OBS networks
Harald Overby, and Norvald Stol
In this paper we present an analytical model, which considers the effects of the switching time on the network performance in service differentiated optical packet/burst switching (OPS/OBS) networks. Our results indicate that the switching time must be less than 10% of the packet/burst duration in order to avoid any siIn this paper we present an analytical model, which considers the effects of the switching time on the network performance in service differentiated optical packet/burst switching (OPS/OBS) networks. Our results indicate that the switching time must be less than 10% of the packet/burst duration in order to avoid any significant reductions in the network performance. Furthermore, regarding a network with full wavelength conversion, we show that the benefits of statistical resource sharing are almost non-existent for low priority traffic when the switching time is large..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03131 (2004)
A novel tunable polarization mode dispersion compensator with strain chirped fiber Bragg gratings
Yumin Liu, Zhongyuan Yu, Yuan Zheng, Xiaoguang Zhang, and Bojun Yang
A tunable polarization mode dispersion (PMD) compensator based on strain-chirped fiber Bragg gratings (FBGs) is proposed. It natures in flexible designing, large tuning range, without using linear or nonlinear chirped phase mask, fast tuning response time, continuously adjustable, all-fiber based, compact, and cheap.A tunable polarization mode dispersion (PMD) compensator based on strain-chirped fiber Bragg gratings (FBGs) is proposed. It natures in flexible designing, large tuning range, without using linear or nonlinear chirped phase mask, fast tuning response time, continuously adjustable, all-fiber based, compact, and cheap..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03135 (2004)
Compensating large PMD by a fiber grating
Tangjun Li, Muguang Wang, Cao Diao, and Shuisheng Jian
In this paper, the first- and second-order polarization mode dispersion (PMD) with the amount of 132.994-ps differential group-delay (DGD) and maximum 476.129-ps/nm second-order PMD can be compensated by a two-stages PMD compensator at a 40-Gb/s optical fiber communication system. The first stage has one free degree thIn this paper, the first- and second-order polarization mode dispersion (PMD) with the amount of 132.994-ps differential group-delay (DGD) and maximum 476.129-ps/nm second-order PMD can be compensated by a two-stages PMD compensator at a 40-Gb/s optical fiber communication system. The first stage has one free degree that is used for first order and high orders PMD compensations by rotating the state of polarization. The second-stage is used for remainder PMD compensations. After compensation, the average DGD and the maximum second-order PMD are reduced to 345.310 fs and 3.102 ps/nm, respectively..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03138 (2004)
Imaging Systems
A united optimum images fusion based on analysis of color distortion
Gang Xiao, Zhongliang Jing, Jianxun Li, and Henry Leung
In remote sensing community, IHS (intensity, hue, and saturation) transform is one of the most commonly used fusion algorithm. A study on IHS fusion indicates that the color distortion cannot be avoided. Meanwhile, wavelet decomposition has a property of frequency division in transform domain. And the statistical propeIn remote sensing community, IHS (intensity, hue, and saturation) transform is one of the most commonly used fusion algorithm. A study on IHS fusion indicates that the color distortion cannot be avoided. Meanwhile, wavelet decomposition has a property of frequency division in transform domain. And the statistical property of wavelet coefficient reflects those significant features. So, a united optimal fusion method, which using the statistical property of wavelet decomposition and IHS transform on pixel and feature levels, is proposed. That is, the high frequency of intensity component I is fused on feature level with multi-resolution wavelet in IHS space, and the low frequency of intensity component I is fused on pixel level with optimal weight coefficients. Spectral information and spatial resolution are two performance indexes of optimal weight coefficients. Experiment results show that it is a practical and effective method..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03144 (2004)
Lasers and Laser Optics
Optimization of linear cavity design of Yb-doped double-clad fiber laser
Ling Zhao, Chunlin Zhang, Lina Li, and Lijun Wang
The output characteristics of a linear cavity Yb-doped double-clad fiber (DCF) laser, including the effects of fiber length, fiber loss, and output mirror reflectivity on laser output power and threshold pump power have been studied theoretically andexperimentally. In this paper, the linear cavity of double-clad fiber The output characteristics of a linear cavity Yb-doped double-clad fiber (DCF) laser, including the effects of fiber length, fiber loss, and output mirror reflectivity on laser output power and threshold pump power have been studied theoretically andexperimentally. In this paper, the linear cavity of double-clad fiber laser (DCFL) was composed of a pair of fiber Bragg gratings, while the facet of fiber was anti-reflection (AR) coated at 1070nm to erase the Fresnel reflection. Analysis showed that the laser output increases as the reflectivity of the fiber Bragg grating used as the output mirror decreases. At last, under the pump power of 14.4 W, single-mode laser output at 1070 nm was up to 10.8 W, with slope efficiency of 75%..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03148 (2004)
Wear resistance of laser cladding and plasma spray welding layer on stainless steel surface
Xinlin Wang, Shihong Shi, and Qiguang Zheng
The effect of coatings, which are formed with laser cladding and plasma spray welding on 1Cr18Ni9Ti base metal, on wear resistance is studied, A 5-kW transverse flowing CO2 laser is used for cladding Co base alloy powder pre-placed on the substrate. Comparing with the plasma spray coatings, the spoiled rate of productsThe effect of coatings, which are formed with laser cladding and plasma spray welding on 1Cr18Ni9Ti base metal, on wear resistance is studied, A 5-kW transverse flowing CO2 laser is used for cladding Co base alloy powder pre-placed on the substrate. Comparing with the plasma spray coatings, the spoiled rate of products with laser clad layers was lower and the rate of finished products was higher. Their microstructure is extremely fine. They have close texture and small size grain. Their dilution resulting from the compositions of the base metal and thermal effect on base metal are less. The hardness, toughness, and strength of the laser cladding layers are higher. Wear tests show that the laser layers have higher properties of anti-friction, anti-scour and high-temperature sliding strike. The wear resistance of laser clad layers are about one time higher than that of plasma spray welding layer..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03151 (2004)
Medical Optics and Biotechnology
Raman spectroscopic studies on the conformational changes of calf thymus DNA induced by Cd2+ ions
Guiqiang Liu, Yaoyong Meng, Songhao Liu, and Yonghong Hu
We used Raman spectroscopy to study the conformational changes of DNA induced by Cd2+ ions in different Cd2+ concentrations solution. The experimental results show that when the Cd^(2+)/PO^(-)_(2) ratio R increased from 0 to 3.0, the band 835.0 cm^(-1) shifted about 8 cm^(-1), and the overlapping spectra of 1446.0 and We used Raman spectroscopy to study the conformational changes of DNA induced by Cd2+ ions in different Cd2+ concentrations solution. The experimental results show that when the Cd^(2+)/PO^(-)_(2) ratio R increased from 0 to 3.0, the band 835.0 cm^(-1) shifted about 8 cm^(-1), and the overlapping spectra of 1446.0 and 1461.0 cm^(-1) separated and moved to 1441.0 and 1458.0 cm^(-1), respectively. This indicates that the conformation of DNA has changed from a "normal" B-form to a "modified" B'-form. At the same time, changes of other bands demonstrate that parts of base stacking collapse and some hydrogen bonds between AT are disrupted, AT base pairs are damaged more larger than GC base pairs..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03154 (2004)
A numerical simulation of photothermal response in laser medicine
Xiaoxia Li, Shifu Fan, Youquan Zhao, and Songshan Xiao
In this paper, we reported a numerical solution of laser induced thermal effect in the bio-tissue. The model of photothermal effect and classical Pennes bio-heat transfer equation were introduced. Finite element method (FEM), which was realized by Matlab software, was used to calculate the temperature distribution. He-In this paper, we reported a numerical solution of laser induced thermal effect in the bio-tissue. The model of photothermal effect and classical Pennes bio-heat transfer equation were introduced. Finite element method (FEM), which was realized by Matlab software, was used to calculate the temperature distribution. He-Ne laser (633 nm) was used to simulate the physical therapy in in vivo skin tissue. Under the cylinder coordinates, the three-dimension (3-D) geometry of tissue was reduced to two-dimension (2-D) computation. The results contained the radial, axial and temperature 3-D color plot. Combining the time animation display was possible. By changing the laser and tissue parameters we can get different results. This will be the initial and indispensable work of the non-destructive evaluation of the laser induced injury..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03157 (2004)
Characteristics of blood fluorescence spectra using low-level, 457.9-nm excitation from Ar+ laser
Shumei Gao, Xiufeng Lan, Ying Liu, Zhonghua Shen, Jian Lu, and Xiaowu Ni
We measured the fluorescence spectra of the whole blood, the red blood cell (RBC) and the hemoglobin using 457.9-nm Ar+ laser excitation. It was found that the fluorescence spectra of the whole blood and the RBC have much similarities in the intensity, the emission peaks and the emitting region, and abundant peaks can We measured the fluorescence spectra of the whole blood, the red blood cell (RBC) and the hemoglobin using 457.9-nm Ar+ laser excitation. It was found that the fluorescence spectra of the whole blood and the RBC have much similarities in the intensity, the emission peaks and the emitting region, and abundant peaks can be found. But for the hemoglobin, fluorescence could only be found in the wavelength range 580-650 nm. It was concluded that in the wavelength range of 650-850 nm, the fluorescence spectra were emitted by the new fluorophores generated by the breakdown of some weak bonds on the RBC membrane, such as the C-C bond and the C-N bond. In the wavelength range of 590-650 nm, the fluorescence spectra are mainly emitted by the hemoglobin, but the hemoglobin solution of cracked RBC has a strong quencher effect on the fluorescence spectrum. The experimental result and the theoretical analysis are meaningful for the medical diagnostics and the therapy..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03160 (2004)
Nonlinear Optics
Colliding-enhanced Cr:LiSAF broad-band phase-conjugate resonator
Chuanwen Ge, Weijun Zhang, and Jun Qu
A novel colliding-enhanced Cr:LiSAF broad-band phase-conjugate resonator (PCR) has been investigated theoretically and experimentally. This kind of PCR is a low initiating threshold resonator. It can produce self-Q-switching narrow pulse with about 35 ns duration (FWHM), efficiently correct intracavity phase aberrationA novel colliding-enhanced Cr:LiSAF broad-band phase-conjugate resonator (PCR) has been investigated theoretically and experimentally. This kind of PCR is a low initiating threshold resonator. It can produce self-Q-switching narrow pulse with about 35 ns duration (FWHM), efficiently correct intracavity phase aberrations, and severalfold improve output laser beam quality..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03165 (2004)
Ultrabroad-band wavelength converter with high flattening conversion efficiency in a semiconductor optical amplifier
Xiaofeng Xu, Jue Wei, Zhihui Kang, Yun Jiang, Huifang Zhang, and Jinyue Gao
The efficiency of ultrabroad-band wavelength conversion using orthogonal-pump four-wave mixing in a semiconductor optical amplifier is measured for the wavelength shifts from 1500 to 1640 nm. The variation of conversion efficiency is <0.9 dB over the wavelength range from 1530 to 1560 nm (C-band), and <4.5 dB oveThe efficiency of ultrabroad-band wavelength conversion using orthogonal-pump four-wave mixing in a semiconductor optical amplifier is measured for the wavelength shifts from 1500 to 1640 nm. The variation of conversion efficiency is <0.9 dB over the wavelength range from 1530 to 1560 nm (C-band), and <4.5 dB over the wavelength range from 1560 to 1610 nm (L-band). The maximum conversion efficiency is about -8.7 dB..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03168 (2004)
Optical Devices
Efficient visible electroluminescence from porous silicon diodes with low driven voltage
Hongjian Li, Baiyun Huang, Danqing Yi, Haoyang Cui, Yingxuan He, and Jingcui Peng
By using n-butylamine as carbon resource, diamond-like carbon film (DLCF) was deposited on the p-n porous silicon (PS) surface by means of a radio-frequency glow discharge plasma system. Electroluminescent (EL) spectra show that EL intensity of the passivated PS diodes increases by 4.5 times and 30-nm blue-shift of EL By using n-butylamine as carbon resource, diamond-like carbon film (DLCF) was deposited on the p-n porous silicon (PS) surface by means of a radio-frequency glow discharge plasma system. Electroluminescent (EL) spectra show that EL intensity of the passivated PS diodes increases by 4.5 times and 30-nm blue-shift of EL peak occurs compared with the diodes without treatment and both of them are stable while the passivated diodes are exposed to the air indoor. The current-voltage (I-V) characteristics exhibit that the passivated diodes have a smaller series resistance and a lower onset voltage. The EL intensity-voltage (I_(EL)-V) relations of the PS devices with different DLCF thicknesses show that only medium DLCF thickness is optimum. These experimental phenomena have been explained based on Raman spectra and IR spectra of the diamond-like carbon films and IR spectra of the passivated PS samples..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03171 (2004)
Thin Films
Optical absorption properties of Ge-Sb-Te films
Ming Fang, Qinghui Li, and Fuxi Gan
The optical properties of monolayer Ge2Sb2Te5 thin films with three different thicknesses prepared by dc magnetron sputtering method at the range of 400-800 nm were studied. The optical absorption coefficients and the optical energy gap (E_(g)) were calculated. The results gave values for the absorption coefficients inThe optical properties of monolayer Ge2Sb2Te5 thin films with three different thicknesses prepared by dc magnetron sputtering method at the range of 400-800 nm were studied. The optical absorption coefficients and the optical energy gap (E_(g)) were calculated. The results gave values for the absorption coefficients in the range of (1.3-7.5)*10^(5) cm^(-1) which were in the high absorption wavelength region of 400-800 nm. The optical energy gaps were 0.684, 0.753 and 0.810 eV corresponding the films thicknesses of 57, 88 and 127 nm, respectively, showing the characteristic of increasing with the increase of the film thickness..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03177 (2004)
Optical properties of ZnO thin films on SiO2 substrates deposited by radio frequency magnetron sputtering
Deping Xiong, Xiqing Zhang, Jing Wang, Peng Lin, and Shihua Huang
The optical properties of both the annealed and as-deposited ZnO thin films by radio frequency (RF) magnetron sputtering on SiO2 substrates were studied. In the annealed films, two pronounced well defined exciton absorption peaks for the A and B excitons were obtained in the absorption spectra, a strong free exciton emThe optical properties of both the annealed and as-deposited ZnO thin films by radio frequency (RF) magnetron sputtering on SiO2 substrates were studied. In the annealed films, two pronounced well defined exciton absorption peaks for the A and B excitons were obtained in the absorption spectra, a strong free exciton emission without deep-level emissions was observed in the photoluminescence (PL) spectra at room temperature. It was found that annealing the films in oxygen dramatically improved the optical properties and the quality of the films..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03179 (2004)
Holography
Study on digital holography with single phase-shifting operation
Yingzong Wang, Yankun Zhen, Hongjun Zhang, and Yuhong Zhang
The digital holography with single phase-shifting operation has been studied. Experimental results and computer-simulated work are presented. The phase-shifting error makes the intensity of primary image decrease and the conjugate image appear in reconstruction. The explicit equation for explaining these effects is givThe digital holography with single phase-shifting operation has been studied. Experimental results and computer-simulated work are presented. The phase-shifting error makes the intensity of primary image decrease and the conjugate image appear in reconstruction. The explicit equation for explaining these effects is given. The calculation of the normalized intercorrelation peak between the input and the reconstruction for different algorithms shows that, when the phase-shifting operation is the main error source, the quality of the image reconstructed from the digital holography with single phase-shifting operation is favorable..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03141 (2004)
Microscopy
Cross-talk correction in dual-labeled fluorescent microarray scanning
Liqiang Wang, Zukang Lu, and Xuxiang Ni
Cross-talk phenomenon in dual-labeled fluorescent microarray scanning is analyzed from cross-excitation and cross-emission. It is turned out that the spectral overlap of the fluorophores is crucial for cross-talk error, and this error can be corrected by an image subtraction method. The experiment was successfully applCross-talk phenomenon in dual-labeled fluorescent microarray scanning is analyzed from cross-excitation and cross-emission. It is turned out that the spectral overlap of the fluorophores is crucial for cross-talk error, and this error can be corrected by an image subtraction method. The experiment was successfully applied to separate the Cy3 channel and the Cy5 channel in microarray scanning. The cross-talk error was reduced from more than 1% to about 0.1%..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03162 (2004)
Spectroscopy
Study on the wavelength calibration of type III concave grating spectrometry system
Li Bai, Ningfang Liao, Zhaojian Li, and Weiping Yang
We discuss and calibrate the spectrometry system based on concave reflection grating. The working principle, structure and parameters of the spectrometry system are introduced. For the wavelength calibration problem, three methods are put forward and discussed in detail with formulation calculation method, circular iteWe discuss and calibrate the spectrometry system based on concave reflection grating. The working principle, structure and parameters of the spectrometry system are introduced. For the wavelength calibration problem, three methods are put forward and discussed in detail with formulation calculation method, circular iteration method and interpolation. Interpolation is used to calibrate the concave reflection grating spectrometry system and the error is less than 1 nm. Four spectrum images that the system collected are given in this paper. The experimental results indicate that a spectrometry system can be based on concave reflection grating and be calibrated by interpolation..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03174 (2004)
Ultrafast Optics
High-order harmonics in static gas target by 795-nm Ti:sapphire femtosecond laser pulses
Yuanqin Xia, Deying Chen, Jianxin Chen, and Qi Wang
The 5th-23rd high-order harmonics generation in rare gases in static gas target with 120-fs, 85-mJ/pulse, 10-Hz laser system was investigated. Compared with the traditional gas target, static gas target is simple to be used in experiment, and the experimental parameters can be easily controlled. The effects on high-ordThe 5th-23rd high-order harmonics generation in rare gases in static gas target with 120-fs, 85-mJ/pulse, 10-Hz laser system was investigated. Compared with the traditional gas target, static gas target is simple to be used in experiment, and the experimental parameters can be easily controlled. The effects on high-order harmonics due to laser intensities (energy), polarization, gas densities, confocal parameter, and phase mismatch were studied in this paper..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03182 (2004)
Measurement of single cycle and sub-cycle pulse duration
Zhenglie Gong, Wenzhuo Ge, Guizhong Zhang, and Wanghua Xiang
This paper suggests that the linear interferometric correlation (LFC) can be used to measure pulse duration of a few cycles, single cycle or even sub-cycle light pulse. The relations between pulsewidth and LFC curve are derived for Gaussian- and hyperbolic secant-shaped pules. This new method abandons focusing, frequenThis paper suggests that the linear interferometric correlation (LFC) can be used to measure pulse duration of a few cycles, single cycle or even sub-cycle light pulse. The relations between pulsewidth and LFC curve are derived for Gaussian- and hyperbolic secant-shaped pules. This new method abandons focusing, frequency doubling and filtering in the traditional second order correlation method, meanwhile the signal-to-noise ratio (SNR) is improved..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 2, Issue 3, 03185 (2004)
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