Journals >Chinese Optics Letters
Contents
2006
Volume: 4 Issue 1
19 Article(s)
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Fiber Optics and Optical Communications
Impact of polarization dependent loss on degree of polarization as feedback signal of polarization mode dispersion
Yang Zhang, Changxi Yang, and Shiguang Li
Polarization dependent loss (PDL) has been recognized as a critical issue because various inline optical components may have nonnegligible PDL effect that interacts with polarization mode dispersion (PMD). We investigated the impact of PMD-PDL interaction on degree of polarization (DOP), which is the most commonly usedPolarization dependent loss (PDL) has been recognized as a critical issue because various inline optical components may have nonnegligible PDL effect that interacts with polarization mode dispersion (PMD). We investigated the impact of PMD-PDL interaction on degree of polarization (DOP), which is the most commonly used feedback signal in PMD compensation. The simulation results of a 40-Gb/s NRZ code optical transmission system show that the maximum PMD increases from approximately 40 ps to more than 45 ps, while minimum DOP declines from approximately 0.6 to approximately 0.2. The interaction of PMD and PDL also induces residual PMD underestimation of 5-8 ps, which causes degradation of PMD compensation performance..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0101 (2006)
All-optical clock recovery from 10-Gb/s NRZ data and NRZ to RZ format conversion
Lina Yin, Yumei Yan, Yunfeng Zhou, Jian Wu, and Jintong Lin
A non-return-to-zero (NRZ) to pseudo-return-to-zero (PRZ) converter consisting of a semiconductor optical amplifier (SOA) and an arrayed waveguide grating (AWG) is proposed, by which the enhancement of clock frequency component and clock-to-data suppression ratio of the NRZ data are evidently achieved. All-optical clocA non-return-to-zero (NRZ) to pseudo-return-to-zero (PRZ) converter consisting of a semiconductor optical amplifier (SOA) and an arrayed waveguide grating (AWG) is proposed, by which the enhancement of clock frequency component and clock-to-data suppression ratio of the NRZ data are evidently achieved. All-optical clock recovery from NRZ data at 10 Gb/s is successfully demonstrated with the proposed NRZ-to-PRZ converter and a mode-locked SOA fiber laser. Furthermore, NRZ-to-RZ format conversion of 10 Gb/s is realized by using the recovered clock as the control light of terahertz optical asymmetric demultiplexer (TOAD), which further proves that the proposed clock recovery scheme is applicable..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0104 (2006)
Observation of a fused dual-fiber sensor head tips by SEM
Xiaoxu Wang, Junxiu Lin, and Dehe Wang
The shape and microstructure of the fiber-optic liquid-level sensor head, which was made of two fusion-spliced multimode optical fibers, were experimentally studied by using scanning electron microscope (SEM) technology in order to optimize the performance characteristic of the fiber sensor head. The parabolic profile The shape and microstructure of the fiber-optic liquid-level sensor head, which was made of two fusion-spliced multimode optical fibers, were experimentally studied by using scanning electron microscope (SEM) technology in order to optimize the performance characteristic of the fiber sensor head. The parabolic profile of the sensor head was found to be better and having length-width ratio from 1.2:1 to 1.3:1. Some other useful possibilities were proposed..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0108 (2006)
Lasers and Laser Optics
Output characteristics analyses of a novel dual-slab laser with an off-axis one-sided stable-unstable resonator
Lingling Zhang, Junqing Meng, Yan Huang, and Qiquan Hu
A novel dual-slab laser with an off-axis one-sided stable-unstable resonator which can compensate for thermal distortion to some extent by flipping the optical beam is described in this paper. The output power, efficiency, and near-field and far-field intensity distributions of the dual-slab laser have been studied. ThA novel dual-slab laser with an off-axis one-sided stable-unstable resonator which can compensate for thermal distortion to some extent by flipping the optical beam is described in this paper. The output power, efficiency, and near-field and far-field intensity distributions of the dual-slab laser have been studied. The results indicate that the novel dual-slab laser has better performance than the normal dual-slab laser with the same off-axis one-sided stable-unstable resonator..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0121 (2006)
All-solid-state doubly resonant sum-frequency continuous-wave laser at 555 nm
Yanfei Lv, Huiming Tan, and Longsheng Qian
A new kind of resonator for doubly resonant continuous-wave (CW) intracavity sum-frequency mixing (SFM) is presented. A coherent radiation of 327 mW at 555 nm is generated by mixing 1342-nm Nd:YVO4 laser and 946-nm Nd:YAG laser. The M2 beam quality factor of the sum-frequency mixed yellow-green laser is less than 1.7. A new kind of resonator for doubly resonant continuous-wave (CW) intracavity sum-frequency mixing (SFM) is presented. A coherent radiation of 327 mW at 555 nm is generated by mixing 1342-nm Nd:YVO4 laser and 946-nm Nd:YAG laser. The M2 beam quality factor of the sum-frequency mixed yellow-green laser is less than 1.7. The low-noise characteristic of the yellow laser is demonitrated..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0125 (2006)
High power red-light GaInP/AlGaInP laser diodes with nonabsorbing windows based on Zn diffusion-induced quantum well intermixing
Kai Zheng, Tao Lin, Li Jiang, Jun Wang, Suping Liu, Xin Wei, Guangze Zhang, and Xiaoyu Ma
The layer structure of GaInP/AlGaInP quantum well laser diodes (LDs) was grown on GaAs substrate using low-pressure metalorganic chemical vapor deposition (LP-MOCVD) technique. In order to improve the catastrophic optical damage (COD) level of devices, a nonabsorbing window (NAW), which was based on Zn diffusion-induceThe layer structure of GaInP/AlGaInP quantum well laser diodes (LDs) was grown on GaAs substrate using low-pressure metalorganic chemical vapor deposition (LP-MOCVD) technique. In order to improve the catastrophic optical damage (COD) level of devices, a nonabsorbing window (NAW), which was based on Zn diffusion-induced quantum well intermixing, was fabricated near the both ends of the cavities. Zn diffusions were respectively carried out at 480, 500, 520, 540, and 580 Celsius degree for 20 minutes. The largest energy blue shift of 189.1 meV was observed in the window regions at 580 Celsius degree. When the blue shift was 24.7 meV at 480 Celsius degree, the COD power for the window LD was 86.7% higher than the conventional LD..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0127 (2006)
Stochastic resonance for signal-modulated pump noise in a single-mode laser
Liangying Zhang, Li Cao, and Fahui Zhu
By adopting the gain-noise model of the single-mode laser in which with bias and periodical signals serve as inputs, combining with the effect of coloured pump noise, we use the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity under the condition of pumpBy adopting the gain-noise model of the single-mode laser in which with bias and periodical signals serve as inputs, combining with the effect of coloured pump noise, we use the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity under the condition of pump noise and quantum noise cross-related in the form of 'delta' function. It is found that with the change of pump noise correlation time, both SNR and the output power will occur stochastic resonance (SR). If the bias signal 'alpha' is very small, changing the intensities of pump noise and quantum noise respectively does not lead to the appearance of SR in the SNR; while 'alpha' increases to a certain number, SR appears..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0130 (2006)
Influence of shielding gas pressure on welding characteristics in CO2 laser-MIG hybrid welding process
Yanbin Chen, Zhenglong Lei, Liqun Li, and Lin Wu
The droplet transfer behavior and weld characteristics have been investigated under different pressures of shielding gas in CO2 laser and metal inert/active gas (laser-MIG) hybrid welding process. The experimental results indicate that the inherent droplet transfer frequency and stable welding range of conventional MIGThe droplet transfer behavior and weld characteristics have been investigated under different pressures of shielding gas in CO2 laser and metal inert/active gas (laser-MIG) hybrid welding process. The experimental results indicate that the inherent droplet transfer frequency and stable welding range of conventional MIG arc are changed due to the interaction between CO2 laser beam and MIG arc in laser-MIG hybrid welding process, and the shielding gas pressure has a crucial effect on welding characteristics. When the pressure of shielding gas is low in comparison with MIG welding, the frequency of droplet transfer decreases, and the droplet transfer becomes unstable in laser-MIG hybrid welding. So the penetration depth decreases, which shows the characteristic of unstable hybrid welding. However, when the pressure of shielding gas increases to a critical value, the hybrid welding characteristic is changed from unstable hybrid welding to stable hybrid welding, and the frequency of droplet transfer and the penetration depth increase significantly..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0133 (2006)
Materials
Enhancement of upconversion luminescence due to the formation of nanocrystals in Er3+-doped tellurite glasses
Gang Zhou, Shixun Dai, Chunlei Yu, Junjie Zhang, Guonian Wang, Lei Wen, and Zhonghong Jiang
Optically transparent Er3+-doped tellurite-based nanocrystallized glasses with the composition of 70TeO2-15Li2O-15Nb2O5-0.5Er2O3 (mol) have been prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nanocrystals in glass matrix appear to be 35-50 nm from the X-ray Optically transparent Er3+-doped tellurite-based nanocrystallized glasses with the composition of 70TeO2-15Li2O-15Nb2O5-0.5Er2O3 (mol) have been prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nanocrystals in glass matrix appear to be 35-50 nm from the X-ray diffraction (XRD) measurement. The microhardness measurement shows that the Vickers hardness values of the nanocrystallized tellurite glasses are larger (33%-62%) than those in the base glass. The Raman spectra imply that the maximum phonon energy of the based glass decreases and shifts from 668 to 638 /cm after heat-treatment. Visible upconversion luminescence and infrared luminescence of the base glass and heat-treated glasses under 980-nm laser diode (LD) excitation are investigated. The 524-, 546- and 656-nm upconversion intensities by 980-nm pumping increase significantly..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0136 (2006)
Thermal stability and frequency up-conversion properties of Er3+-doped oxyfluoride tellurite glasses
Dongbing He, Junjie Zhang, Guonian Wang, Zhongchao Duan, Shixun Dai, and Lili Hu
The thermal properties of 68TeO2-15BaF2-5SrF2-10LaF3-2KF glass were measured by different temperature analysis (DTA). Up-conversion luminescence of Er3+ ion in the obtained glass was investigated. Mechanism of up-conversion emission was discussed. The result shows that the obtained oxyfluoride tellurite glass 68TeO2-15The thermal properties of 68TeO2-15BaF2-5SrF2-10LaF3-2KF glass were measured by different temperature analysis (DTA). Up-conversion luminescence of Er3+ ion in the obtained glass was investigated. Mechanism of up-conversion emission was discussed. The result shows that the obtained oxyfluoride tellurite glass 68TeO2-15BaF2-5SrF2-10LaF3-2KF has a good thermal stability ('Delta'T = 153.6 Celsius degree) and strong up-conversion green emissions around 527 nm and 549 nm and red emission at 660 nm. This glass can be a promising host material for up-conversion fiber lasers..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0139 (2006)
Photo-induced reorientation of molecules in dye micro crystals
Tariel D. Ebralidze, and Nadia A. Ebralidze
Upon massive generation of anisotropic grains of azo dye methyl orange in a gelatin film exposed to active polarized light, a cluster of micro crystals with optical axes of similar orientations has been produced. The anisotropy observed has been found to disappear under exposure to active natural light.Upon massive generation of anisotropic grains of azo dye methyl orange in a gelatin film exposed to active polarized light, a cluster of micro crystals with optical axes of similar orientations has been produced. The anisotropy observed has been found to disappear under exposure to active natural light..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0143 (2006)
Medical Optics and Biotechnology
Determining particle size distribution and refractive index in a two-layer tissue phantom by linearly polarized light
Yong Deng, Qiang Lu, and Qingming Luo
We report a new method for measuring particle size distribution (PSD) and refractive index of the top layer in a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearly polarized light. The polarization gating technique is used to decouple the single and multiple scatterinWe report a new method for measuring particle size distribution (PSD) and refractive index of the top layer in a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearly polarized light. The polarization gating technique is used to decouple the single and multiple scattering components in the returned signal. The theoretical model based on Mie theory is presented and a nonlinear inversion method -- floating genetic algorithm -- is applied to inverting the azimuth dependence of component of polarization light backscattered. The experiment results demonstrate that the size distribution and refractive index of the scatters of the top layer can be determined by measuring and analyzing the differential signal of the parallel and perpendicular components from a two-layer tissue phantom. The method implies to detect precancerous changes in human epithelial tissue..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0145 (2006)
Nonlinear Optics
The dependence of high-order harmonic generation on the laser frequency and inter-nuclear distance from multi-atom molecular ions
Yufeng Wang, Zhenrong Sun, Xiangyun Zhang, Jun Xiao, Li Deng, Weiping Zhang, Zugeng Wang, and Zhinan Zeng
High-order harmonic generation from one-dimensional (1D) multi-atom molecular ions in an ultra-short laser field is theoretically investigated. The dynamics of the electron in a linearly polarized intense laser field is analyzed in terms of 1D Schrodinger equation with the Crank-Nicolson algorithm. The dependence of hiHigh-order harmonic generation from one-dimensional (1D) multi-atom molecular ions in an ultra-short laser field is theoretically investigated. The dynamics of the electron in a linearly polarized intense laser field is analyzed in terms of 1D Schrodinger equation with the Crank-Nicolson algorithm. The dependence of high-order harmonics on the laser frequency and the inter-nuclear distance is discussed. It is found that the optimum range of inter-nuclear distance should be changed to get extended harmonic generation for different laser frequency, and the lower frequency laser pulse is favorable to higher order harmonic generation as the inter-nuclear distance increases..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0149 (2006)
Optical Devices
Optical transmission enhancement by a sub-wavelength film lens
Fei Zhou, Wendong Xu, Yang Wang, and Fuxi Gan
A new sub-wavelength metallic film lens configuration is proposed, which is embedded in a thin ideal metal film, and its near field optical properties are investigated by finite-difference time-domain (FDTD) method. It is found that the optical transmission is greatly enhanced, and the spot size can be reduced by the sA new sub-wavelength metallic film lens configuration is proposed, which is embedded in a thin ideal metal film, and its near field optical properties are investigated by finite-difference time-domain (FDTD) method. It is found that the optical transmission is greatly enhanced, and the spot size can be reduced by the sub-wavelength metallic film lens in comparison with the bare aperture. This kind of lens is expected to have practical applications in the very small aperture laser (VSAL), a promising nanosource for near-field optical storage and lithography..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0152 (2006)
Thin Films
Atmosphere corrosion behavior of plasma sprayed and laser remelted coatings on copper
Gongying Liang, T. T. Wong, Geng An, and J. M. K. MacAlpine
Nickel and chromium coatings were produced using plasma spraying and laser remelting on the copper sheet. The corrosion test was carried out in an acidic atmosphere, and the corrosive behaviors of both coatings and original copper samples were investigated by using an impedance comparison method. Experimental results sNickel and chromium coatings were produced using plasma spraying and laser remelting on the copper sheet. The corrosion test was carried out in an acidic atmosphere, and the corrosive behaviors of both coatings and original copper samples were investigated by using an impedance comparison method. Experimental results show that nickel and chromium coatings display better corrosion resistance properties relative to the original pure copper sample. The corrosion rate of chromium coating is less than that of nickel coating, and corrosion resistances of laser remelted nickel and chromium samples are better than those of plasma sprayed samples. The corrosion deposit film of copper is loose compared with nickel and chromium..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0159 (2006)
Holography
Complex-wave retrieval based on blind signal separation
Xiaodong Chai, Chengpeng Zhou, Zhaoyan Feng, Yinhua Wang, and Yansheng Zuo
In the process of the reconstruction of digital holography, the traditional methods of diffraction and filtration are commonly adopted to recover the original complex-wave signal. Influenced by twin-image and zero-order terms, the above-mentioned methods, however, either limit the field of vision or result in the loss In the process of the reconstruction of digital holography, the traditional methods of diffraction and filtration are commonly adopted to recover the original complex-wave signal. Influenced by twin-image and zero-order terms, the above-mentioned methods, however, either limit the field of vision or result in the loss of the amplitude and phase. A new method for complex-wave retrieval is presented, which is based on blind signal separation. Three frames of holograms are captured by a charge coupled device (CCD) camera to form an observation signal. The term containing only amplitude and phase of complex-wave is separated, by means of independent component analysis, from the observation signal, which effectively eliminates the zero-order term. Finally, the complex-wave retrieval of pure phase wavefront is achieved. Experimental results show that this method can better recover the amplitude and phase of the original complex-wave even when there is a frequency spectrum mixture in the hologram..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0111 (2006)
Quantum Optics
Absorption resonances in 'Lambda'-type three-level system in cesium vapor cell with buffer gas
Jie Ma, Yanting Zhao, Lirong Wang, Jianming Zhao, Liantuan Xiao, and Suotang Jia
We report experimentally the transformation from the electromagnetically induced transparency (EIT) resonance to a dispersion-like signal and eventually to a nearly symmetric absorption resonance as coupling detuning increases in 'Lambda'-type three-level system in the cesium vapor cell with buffer gas at room We report experimentally the transformation from the electromagnetically induced transparency (EIT) resonance to a dispersion-like signal and eventually to a nearly symmetric absorption resonance as coupling detuning increases in 'Lambda'-type three-level system in the cesium vapor cell with buffer gas at room temperature. The observed absorption resonance occupies some remarkable properties of the strong amplitude and the narrow linewidth in comparison with the case without buffer gas. The relation between linewidth of the enhanced absorption resonance and buffer gas pressure is studied. With pressure increasing, linewidth of the absorption resonance becomes narrow. The sub-natural linewidth is observed in Doppler-broadened cesium vapor cell in our experiment. The experimental results are in qualitative agreement with the numerical simulations..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0155 (2006)
Instrumentation, Measurement, and Metrology
Visibility in magnetostrictive fiber-optic interferometric sensors and its dependence on the input SOP
Changhai Shi, Jianping Chen, Xinwan Li, Ailun Ye, Junhe Zhou, Yi Zhang, Qing Xue, and Lin Hong
The visibility in magnetostrictive fiber-optic interferometric sensors using a Gaussian laser beam is analyzed. It is shown that the conventional Gaussian laser beam has little influence on the visibility. The visibility depends strongly on the input state of polarization (SOP). We implement a cylindrical transducer anThe visibility in magnetostrictive fiber-optic interferometric sensors using a Gaussian laser beam is analyzed. It is shown that the conventional Gaussian laser beam has little influence on the visibility. The visibility depends strongly on the input state of polarization (SOP). We implement a cylindrical transducer and build a measurement setup with a polarization controller. The visibility dependent on the SOP of input light is measured. The estimated values are similar to the experiment results, which verifies the analysis..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0115 (2006)
A position sensor based on grating projection with spatial filtering and polarization modulation
Jianming Hu, Aijun Zeng, and Xiangzhao Wang
A position sensor based on grating projection with spatial filtering and polarization modulation is presented. A grating is projected onto the object to be measured through a 4f optical system with a spatial filter. After reflected by the object, the grating projection is imaged on a detection grating through another 4A position sensor based on grating projection with spatial filtering and polarization modulation is presented. A grating is projected onto the object to be measured through a 4f optical system with a spatial filter. After reflected by the object, the grating projection is imaged on a detection grating through another 4f optical system to form moire fringes. The polarization modulated moire signal is detected to obtain the position information of the object. In the position sensor, the moire signal varies sinusoidally with the position of object. The measurement is independent of the incident intensity on the projection grating and the reflectivity of the object to be measured. In experiments, the effectiveness of the position sensor is proved, and the root mean square (RMS) error at each measurement position is less than 13 nm..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 4, Issue 1, 0118 (2006)
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