Contents
2004
Volume: 24 Issue 5
31 Article(s)
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Research Article
High-Resolution Measurements of Line Strength of Methane at 2ν3 Band R9 Manifold
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The direct absorption spectra of methane at 2ν3 band R9 manifold are measured within the wavelength range of 1637.64～1637.85 cm-1 (in vacuum) by ECDL (external-cavity diode laser), and the absorption line strength corresponding to those are worked out through Voigt fitting. In addition, these results are compared with The direct absorption spectra of methane at 2ν3 band R9 manifold are measured within the wavelength range of 1637.64～1637.85 cm-1 (in vacuum) by ECDL (external-cavity diode laser), and the absorption line strength corresponding to those are worked out through Voigt fitting. In addition, these results are compared with those that have been done by Jack S. Margolis with Fourier transform infrared spectrometer and the error is analyzed. The experiment and the calculation represent that the biggest error is 3.9%; the smallest error is 0.02% for eight absorption lines. Except the line 3 and the line 4, the results are comprehensible. The acquired data are used to remote sensing of the concentration of methane. The methods of the measurement and the calculation here also can be applied to measure the absorption line strength of CO, CO2, NH3 etc...
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 709 (2004)
Atmospheric Optics and Oceanic Optics
Profile and Character of Atmospheric Temperature
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The factors that affect turbulence and space-time structure are comparatively complex, the distribution of average stream and atmospheric temperature is not uniform. Especially, the vertical distribution of temperature decides caloric instability in vertical and size of turbulence. It is shown by observated results thaThe factors that affect turbulence and space-time structure are comparatively complex, the distribution of average stream and atmospheric temperature is not uniform. Especially, the vertical distribution of temperature decides caloric instability in vertical and size of turbulence. It is shown by observated results that the vertical profile of temperature T is changed by the different season and weather condition. The vertical profile of temperature and mode error is gained with balloon borne instrument in Hefei (0～20 km). The atmospheric structure of refractive index C2n is a important parameter denoting turbulence. But, measuring of atmospheric refractive index is quite difficult, so usually the variation of temperature is measured and C2n is gained by average temperature and air pressure. An anslysis of mode error of temperature and air pressure is performed for the mode error of C2n. An analysis is performed for the vertical distribution of temperature T and the mode error. Also, the relationship of C2n and temperature T is discussed. And the effect of counting structure constant of refractive index C2n by mode error is also discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 592 (2004)
L625 Differential Absorption Lidar System for Tropospheric Ozone Measurements
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The L625 differential absorption lidar (DIAL) is introduced to measure vertical ozone profiles in the troposphere. System structure, measurement principle and data processing are also described. Comparison measurements of middle and upper tropospheric ozone are made with a couple of wavelength pairs of 289～299 nm and 2The L625 differential absorption lidar (DIAL) is introduced to measure vertical ozone profiles in the troposphere. System structure, measurement principle and data processing are also described. Comparison measurements of middle and upper tropospheric ozone are made with a couple of wavelength pairs of 289～299 nm and 289～308 nm at Hefei. Measurement results show that the differences between this couple is about 10%. Statistic errors below 10 km altitude are usually less than 2×1011 molecules per cubic centimeter in tropospheric ozone measurement by wavelength pair of 289～308 nm. Systematic errors due to aerosol loading are commonly less than 4%. Characteristics of seasonal variation of tropospheric ozone column contents from 5～15 km altitude are given and analyzed over Hefei. Maximal tropospheric ozone column contents occurred in the second quarter and minimal contents in the third quarter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 597 (2004)
Estimating Method of Detecting Minimum Pollutant Gas Concentration by Lidar
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Detecting the density of pollutant gas is one of the important applications of lidar. The minimum detectable concentration is a key index of lidar. According to error theory, the estimating method of detectable minimum quantity is obtainedDetecting the density of pollutant gas is one of the important applications of lidar. The minimum detectable concentration is a key index of lidar. According to error theory, the estimating method of detectable minimum quantity is obtained.
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 602 (2004)
Fiber Optics and Optical Communications
Analysis of White-Light Interference Distributed Optic Fiber Sensor by Polarized Modes Coupling
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The distributed optical fiber sensors can measure the environment factors which continuously distributed along a length of optical fiber. For a distributed fiber sensor taking a polarization-maintaining fiber as sensing fiber, the environment factors induce the orthogonal polarization modes propagated in the fiber coupThe distributed optical fiber sensors can measure the environment factors which continuously distributed along a length of optical fiber. For a distributed fiber sensor taking a polarization-maintaining fiber as sensing fiber, the environment factors induce the orthogonal polarization modes propagated in the fiber coupling each other. The sensing signal is detected by means of compensating the optical path difference of the two orthogonal polarization modes by two arms path difference of Michelson interferometer. In order to design white light interference distributed optical fiber sensor by polarized modes coupling, the mutual coherent characteristics of the sensor were analyzed according to the principle of statistic optics. On these bases, the length resolution, fiber coupling point resolution and maximum sensing fiber spatial of the sensor were obtained. The length resolution and the coupling point resolution are 6 cm and 3 mm respectively for a distributed optical fiber sensor with a superradiant light-emitted diode(SLD) source of center wavelength 1310 nm, spectral width 36 nm and a polarization-maintaining fiber of polarization dispersion coefficient 600 ps/km and beat length 3 mm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 605 (2004)
Temperature Effect of Amplified Anti-Stokes Raman Spontaneous Backscattering in the Single Mode Fiber
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Amplified anti-Stokes Raman spontaneous backscattering phenomena has been observed in single mode fiber, during input laser power is large than threshold power. In experiment it is discovered, the temperature effect of the amplified anti-Stokes Raman spontaneous backscattering is excised as some as anti-Stokes Raman spAmplified anti-Stokes Raman spontaneous backscattering phenomena has been observed in single mode fiber, during input laser power is large than threshold power. In experiment it is discovered, the temperature effect of the amplified anti-Stokes Raman spontaneous backscattering is excised as some as anti-Stokes Raman spontaneous backscattering. The photon flux of amplified anti-Stokes Raman spontaneous backscattering is modulated by optical fiber temperature. The coherent noise of single mode fiber is restrained by the amplification effect of anti Stokes Raman backscattering, and the signal noise ratio of sensor system is improved. Experimental discover, the extremity point position on the amplified anti-Stokes Raman spontaneous backscattering space domain reflection curve is forward shifted with laser power raised, and obeys certain rule. The temperature effect of the amplified anti-Stokes Raman spontaneous backscattering has been applied to long range 30 km distributed optical fiber Raman temperature sensor system as a new principle of temperature measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 609 (2004)
Study on Improving the Performance of Thin Film Filter Based DWDM Components
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Two approaches of building DWDM component incorporated with optical interleaver and thin film filter modules are discussed. A novel structure is proposed to improve the insertion loss uniformity, channel isolation, and the total crosstalk of such DWDM component. Theoretic analysis and experiment were performed on both Two approaches of building DWDM component incorporated with optical interleaver and thin film filter modules are discussed. A novel structure is proposed to improve the insertion loss uniformity, channel isolation, and the total crosstalk of such DWDM component. Theoretic analysis and experiment were performed on both the novel and conventional structure, and the result indicated that the side lobe of the novel structure′s spectrum is depressed from -30 dB of the conventional structure′s to about -50 dB. DWDM experiment by using at a 16 channel 50 GHz indicates that an improvement of 0.869 dB on insertion loss, 2.005 dB on insertion loss uniformity, 1.004 dB on adjacent channel isolation, 42.903 dB on non-adjacent channel isolation and 1.68 dB on total crosstalk. The novel approach can be used not only in the ultra-DWDM based on interleaver and thin film filter module cascaded, but also in DWDM based on array waveguide grating (AWG) to mitigate the technical difficulty and improve the specifications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 651 (2004)
Differential Mode Delay in POF Measured by Frequency-Domain Phase-Shift Technique
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Knowledge of differential mode delay data of polymer optical fiber plays an important role in studying the dispersion characteristic of the fiber. Differential mode delay of step index-polymer optical fiber (SI-POF) and gradient index-polymer optical fiber (GI-POF) with various lengths is measured by the frequency-domaKnowledge of differential mode delay data of polymer optical fiber plays an important role in studying the dispersion characteristic of the fiber. Differential mode delay of step index-polymer optical fiber (SI-POF) and gradient index-polymer optical fiber (GI-POF) with various lengths is measured by the frequency-domain phase-shift technique. Due to the fact that the mode coupling and the mode-dependent loss can be neglected for short fibers, the measured values of the differential mode delay for the 1 m fibers agree well with the theoretical ones. Therefore, the frequency-domain phase-shift technique provides a simple, convenient way to determine the differential mode delay of the polymer fibers with high accuracy. In addition, the mode coupling of POF can be analyzed to some extent by comparing the differential mode delay curves of the fibers with various lengths..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 655 (2004)
Fourier Optics and Signal Processing
Correction Algorithm of Random Phase Shifting Errors in Phase Measuring Profilometry
[in Chinese], [in Chinese], and [in Chinese]
In phase-measuring profilometry (PMP), the random phase shifting errors is a important factor that leads to measuring errors. A new correction algorithm of random phase shifting errors is proposed on the basis of five-step. The new algorithm can directly solve random phase shifting errors without solving the phase by aIn phase-measuring profilometry (PMP), the random phase shifting errors is a important factor that leads to measuring errors. A new correction algorithm of random phase shifting errors is proposed on the basis of five-step. The new algorithm can directly solve random phase shifting errors without solving the phase by approximate treatment. It can greatly reduce the number of iteration and calculation with the intended accuracy. The formulas of the new algorithm is induced and the process to solve random phase shifting is indicated in detail. The validity of this algorithm has been demonstrated by means of compute simulation and experiment. It can greatly reduce the number of iteration and calculation in comparison with the algorithm of In-Bok Kong. The new algorithm can also apply in phase-shifting interferometry..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 614 (2004)
Imaging Through Highly Scattering Media Using Fresnel Zone Plate Scanning Holography
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Fresnel zone plate scanning holography is applied in the imaging through highly scattering media. The background noise of the reconstructed image is resulted from the nonnegative coded function. A method of constructing composite hologram for reducing the background noise is proposed. The reconstructions with good-The Fresnel zone plate scanning holography is applied in the imaging through highly scattering media. The background noise of the reconstructed image is resulted from the nonnegative coded function. A method of constructing composite hologram for reducing the background noise is proposed. The reconstructions with good-quality signal-to-noise ratio (SNR) and contrast ratio are obtained in experiments using this method. The system point spread function (PSF) is designed to be similar to the Dirac delta function. The experimental results and the theoretical calculation of the PSF are in accordance. The experiments on absorbers embedded in the intralipid solution with concentration of 1% and depth of 1.7 cm are implemented. The results demonstrate that the reconstructions of the metal ring with diameter of 6.0 mm and the metal wire with diameter of 0.4 mm are clear. The reconstruction of the black plastic ball with diameter of 2.5 mm is also satisfied..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 619 (2004)
Information Hiding Theory Based on Virtual Optics and Its Implementation with Parallel Hardware
[in Chinese], [in Chinese], and [in Chinese]
optical encryption technology has been a subject of receiving many research efforts because of inherently parallel nature of optical information processing, high security strength and huge degree of freedom for key design. Optical security technology has appeared very promising and is likely the next generation of infooptical encryption technology has been a subject of receiving many research efforts because of inherently parallel nature of optical information processing, high security strength and huge degree of freedom for key design. Optical security technology has appeared very promising and is likely the next generation of information security. An implementation of virtual-optics based encryption with a parallel hardware strategy is presented. A TMS320C6000 digital signal processor is used to design an information hiding system with multiple-locks and multiple-keys. An evaluation of the system performance is made and it is shown that the encryption and decryption of digital information in real-time can be achieved with such a strategy. This approach paves the way for the realization of virtual-optics based methodology by combining major advantages of optical encryption and electronic encryption..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 623 (2004)
A New Rectification Method of Stereo Pairs Without Calibration for Cameras
[in Chinese], and [in Chinese]
The binocular stereovision is a primary approach to realize optical passive 3-D measurement. To search corresponding points fast and accurately, the stereo pairs must be rectified. A method is presented to rectify stereo pairs without calibration for cameras. In this method the initial values of perspective projective The binocular stereovision is a primary approach to realize optical passive 3-D measurement. To search corresponding points fast and accurately, the stereo pairs must be rectified. A method is presented to rectify stereo pairs without calibration for cameras. In this method the initial values of perspective projective matrix; rotative matrix and translative matrix are calculated from the fundamental matrix, than these matrices are optimized based on the coordinate value of corresponding points. This method can avoid the local least value in the optimal calculation effectively, and the dependence on the calculation precision of the fundamental matrix excessively. By the experiment of image rectification to compare this method put forward this here with two typical methods that one depend on fundamental matrix calculation and the other dispenses with fundamental matrix calculation, it is shown that this method can rectify stereo pairs fast and accurately, but bring little image distortion..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 628 (2004)
Instrumentation, Measurement and Metrology
Measurement of Absolute Concentration of Both O2(1Δ) and Water Vapor in Outlet Stream of Singlet Oxygen Generator
[in Chinese], [in Chinese], and [in Chinese]
As the energy source of the chemical oxygen iodine laser (COIL) the singlet oxygen generator (SOG) is a key part of the COIL, and consequently, the concentration of O2(1Δ) and water vapor is two important parameters for the SOG. The concentration of water vapor is another important parameter for the SOG because water cAs the energy source of the chemical oxygen iodine laser (COIL) the singlet oxygen generator (SOG) is a key part of the COIL, and consequently, the concentration of O2(1Δ) and water vapor is two important parameters for the SOG. The concentration of water vapor is another important parameter for the SOG because water can strongly quench I* which is the luminesent medium of COIL. It is a difficult problem how to measure the two parameters easily and accurately. The piston source method has been used to measure the absolute concentration of O2(1Δ) and water vapor in a jet-type SOG. Some curves about the O2(1Δ) yield and water vapor concentration also has been given. The change law of the varions parameters is given from a quantity of experimental results. These results offer references for studying the jet-SOG..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 683 (2004)
A New Method for Getting High Precision Phase in Structural Light Measurement
[in Chinese], [in Chinese], and [in Chinese]
With the development of manufacturing technology, the three-dimensional optic measurement technology is developed rapidly. Projection measurement with two cameras is a new kind of optical measurement technique. In the measurement process, the measurement space can be got by the phase value. In order to get high precisiWith the development of manufacturing technology, the three-dimensional optic measurement technology is developed rapidly. Projection measurement with two cameras is a new kind of optical measurement technique. In the measurement process, the measurement space can be got by the phase value. In order to get high precision measuring phase for the technique, a phase-shifting method is proposed with Gray code. The method can calculate the phase value by projected phase transfer function and irradiance function of projected structural light. The non-sinusoidal, non-periodical effects of projected structural light are considered. The precision of strip and phase is improved by the method. The result precision of phase can reach sub-pixel by interposition..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 687 (2004)
Lasers and Laser Optics
Characteristic of Liner LDs Side-Pumped Nd∶YAG Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Starting from the four-level system rate-equations, the relationship between output parameters and pump parameters in multi-mode solid-state laser has been deduced. For a three liner laser diode side-pumped symmetry in laser diode-pumped solid-state lasers, the pump intensity distribution is calculated, and series numeStarting from the four-level system rate-equations, the relationship between output parameters and pump parameters in multi-mode solid-state laser has been deduced. For a three liner laser diode side-pumped symmetry in laser diode-pumped solid-state lasers, the pump intensity distribution is calculated, and series numerical calculations relating to the relationship between output parameters (such as threshold pump power, slope efficiency, output power and beam performance) and pump parameters are conducted. It can be seen that both radius of Nd∶YAG crystal and of pump beam waist are main factors to affect output power and beam performance. The beam performance has been improved obviously by mode-selecting with a small aperture. A set of parameters in three Liner laser diode side-pumped symmetry have been chosen to test the numerical calculation results experimentally. The experimental results are consistent to calculated ones..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 633 (2004)
High Repetition Rate Electro-Optically Q-Switched Nd∶YVO4 Slab Laser with High Beam Quality Output
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Partially end-pumped slab laser using hybrid resonator is a favourable concept to scale high power with high beam quality in compact dimension. Nd∶YVO4 have the advantages of large laser cross section and short fluorescence lifetime. These features are required in high repetition rate short pulse length applications. APartially end-pumped slab laser using hybrid resonator is a favourable concept to scale high power with high beam quality in compact dimension. Nd∶YVO4 have the advantages of large laser cross section and short fluorescence lifetime. These features are required in high repetition rate short pulse length applications. A electro-optically Q-swithced slab laser with hybrid resonator has been realized. High repetition rate pulse with high beam quality output was measured. At 5 kHz operation, Q-swithced laser with pulse energy of 7.2 mJ and pulse width of 5.7 ns was obtained. The energy and width were 1.6 mJ and 9.5 ns respectively when the repetition rate reached 50 kHz. The beam quality factor M2 was lower than 2..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 641 (2004)
Actively-Passively Mode-Locked Erbium-Doped Fiber Laser with Dispersion-Imbalanced Nonlinear Optical Loop Mirror
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Simulation of the dispersion-imbalanced nonlinear optical loop mirror′s transmission characteristics with different parameters is made. The physical mechanism of using dispersion-imbalanced nonlinear optical loop mirror to compress pulse in mode-locked fiber laser is analyzed theoretically. 11 ps stable mode-locked pulSimulation of the dispersion-imbalanced nonlinear optical loop mirror′s transmission characteristics with different parameters is made. The physical mechanism of using dispersion-imbalanced nonlinear optical loop mirror to compress pulse in mode-locked fiber laser is analyzed theoretically. 11 ps stable mode-locked pulse train at 1566.65 nm with the modulation frequency of 9.998748700 GHz is obtained by using figure-eight actively-passively structure. Meanwhile, 2～3 harmonic mode-locked pulses with uniform amplitude are obtained at the modulation frequency of 9.995792825 GHz and 9.996778256 GHz respectively. It is demonstrated that dispersion-imbalanced nonlinear optical loop mirror can effectively eliminate the wings and noise of pulse to obtained pulse train with uniform amplitude..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 645 (2004)
Materials
Er3+-Doped Tungsten-Tellurite Glasses for Broadband Optical Amplifier
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Er3+-doped TeO2-WO3-ZnO-ZnF2(TWZOF) glasses were prepared. The absorption spectra, 1.5 μm emission spectra and fluorescence lifetimes of Er3+, excited at 970 nm, were measured. The J-O parameters Ωt (t=2,4,6), absorption and emission cross-sections were calculated by Judd-Offelt theories and McCumber theory, respecThe Er3+-doped TeO2-WO3-ZnO-ZnF2(TWZOF) glasses were prepared. The absorption spectra, 1.5 μm emission spectra and fluorescence lifetimes of Er3+, excited at 970 nm, were measured. The J-O parameters Ωt (t=2,4,6), absorption and emission cross-sections were calculated by Judd-Offelt theories and McCumber theory, respectively. The dependence of the content of ZnF2 in glass composition upon 1.5 μm emission intensity, fluorescence lifetime and bandwidth of Er3+ was investigated. In TWZOF glass, Er3+ ion had a large emission cross-section with a peak value of 0.86 pm2. Er3+ ions also had a broad 1.5 μm emission spectrum in the glass, which had a FWHM between 68 nm and 83 nm. The maximum FWHM demonstrated here was 83 nm. Er3+ ion had a large value of Ω6 and a small value of Ω2 in TWZOF glass. With the increasing of the content of ZnF2, The Ω2 and the Ω6 both increased. The emission intensity at peak wavelength and the fluorescence lifetime of Er3+ at 1.5 μm also increased with the increasing of the content of ZnF2..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 673 (2004)
Study on Er3+-Doped and Er3+/Yb3+ Co-Doped Bismuth Borate Glasses
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Some bismuth borate glasses with Er3+-doped and Er3+/Yb3+ co-doped are fabricated by the technique of high-temperature melting. The absorption and fluorescence spectra, fluorescence lifetime and transmission in infrared range are measured. Explanation of concentration quenching in case of high level Er3+-doped the bismSome bismuth borate glasses with Er3+-doped and Er3+/Yb3+ co-doped are fabricated by the technique of high-temperature melting. The absorption and fluorescence spectra, fluorescence lifetime and transmission in infrared range are measured. Explanation of concentration quenching in case of high level Er3+-doped the bismuth borate glasses is given. The sensitizing of Yb3+ to Er3+ in Er3+/Yb3+ co-doped bismuth borate glasses is discussed. It is found that the band around 1.5～1.6 μm in Er3+/Yb3+ co-doped bismuth borate glass reaches 81 nm and the fluorescence lifetime of Er3+ is enhanced obviously when the glass is treated with oxygen in melting process. In the meantime the glasses show favorable chemical and physical properties. It is expected to be a favorable candidate host for broadband amplifiers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 678 (2004)
Optical Devices
Optimized Pack of High-Speed Photodiode
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel optimization for packaging high-speed photodiodes is presented. All the packaging parasitics and the intrinsic characteristic parameters of the photodiode chip are accurately measured with microwave network analyzer. The resonance among them is investigated. The resonance is utilized to significantly improve thA novel optimization for packaging high-speed photodiodes is presented. All the packaging parasitics and the intrinsic characteristic parameters of the photodiode chip are accurately measured with microwave network analyzer. The resonance among them is investigated. The resonance is utilized to significantly improve the frequency response of the devices. Both theoretical and experimental results show that the packaged photodiodes can have a 3 dB bandwidth which is broader than that of the photodiode chip. This method, which utilizes the parasitic inductance of necessary bonding wires, can be used to improve the frequency response of optoelectronics devices without any additional component, only by using parasitic inductance induced by gold wire which is essential in packing process of optoelectronic devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 659 (2004)
Super-Flat-Wideband Single-Mode Optical Fiber Couplers Ranged from 1250 nm to 1650 nm
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Fiber-optic passive devices are so suitable for current situation that they have greatly been grown with rapid developments and broad applications of optical fiber technology, within which optical fiber fused tapering devices are more noticeable due to their simple manufacture, stable performance, cheaper price and supFiber-optic passive devices are so suitable for current situation that they have greatly been grown with rapid developments and broad applications of optical fiber technology, within which optical fiber fused tapering devices are more noticeable due to their simple manufacture, stable performance, cheaper price and super specification. Among the above ones, optical fiber couples are widely used as fundamental devices. Recently, super-flat-wideband single-mode optical fiber couplers become a popular research area with urgent development of all-fiber communications. Super-flat-wideband single-mode optical fiber couplers have been developed by the architectural method of special phase compensation, whose operating wavelength band is from 1250 nm to 1650 nm, 3 dB-insertion-loss maximum deviation within the band is less than 0.4 dB, maximum excess loss within the band is less than 0.1 dB, directionality is greater than 66.5 dB, and polarized dependent loss is less than 0.1 dB. In the light of the method high rate of the finished products, meanwhile, a batch productions are feasible..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 663 (2004)
Analysis of Nonpolarizing Narrow-Band Filters Based on Resonant Anomaly
[in Chinese], and [in Chinese]
Subwavelength gratings with different grating parameter have different diffractive properties, and realization of nonpolarizing narrow-band filtering by reasonably designing the parameter of subwavelength grating is a novel method and approach. Based on resonant anomaly, physical mechanism of narrow-band filtering and Subwavelength gratings with different grating parameter have different diffractive properties, and realization of nonpolarizing narrow-band filtering by reasonably designing the parameter of subwavelength grating is a novel method and approach. Based on resonant anomaly, physical mechanism of narrow-band filtering and its condition was analyzed, and probability for realization of nonpolarizing narrow-band filtering in two-dimensional subwavelength gratings was discussed. Using rigorous modal theory, its simulation results were consistent with those of guided-wave theory, in which location of resonant anomaly appear periodically and diffraction efficiency is very sensitive to not only incidence angle but also wavelength. At last, fabrication errors effecting diffractive properties were analysed, which, to some degree, are useful to concrete fabrication..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 668 (2004)
Physical Optics
Study on Birefringent Filter for Broad-Bandwidth Femtosecond Pulse
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The birefringent interference filter for broad-bandwidth femtosecond pulse is investigated theoretically and experimentally. The principle and design of a novel birefringent filter are presented based on the interference of polarized light, the analytical formulation of transmission and reflection spectra out of the fiThe birefringent interference filter for broad-bandwidth femtosecond pulse is investigated theoretically and experimentally. The principle and design of a novel birefringent filter are presented based on the interference of polarized light, the analytical formulation of transmission and reflection spectra out of the filter is obtained. The experiments of the filter for 15 fs broad-bandwidth pulse have been carried out, a group of good transmittance and reflection filter spectra is obtained in the experiments, the experimental measurements are in agreement with the theory. Moreover, the influence of the group velocity mismatch (GVM) and group velocity dispersion (GVD) on the filter for broad-bandwidth femtosecond pulse is analyzed. The results demonstrate that the filter is feasible and efficient for broad-bandwidth femtosecond pulse, and there is no power depletion since it allow output of the forward transmission and lateral reflection spectra synchronously. This kind of filter can be applied to developing stable multi-wavelength and tunable ultrashort pulse sources. The results can be importantly referenced by design and application of this kind of filter for femtosecond pulse..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 577 (2004)
Measurement of Second Order PMD with Poincaré Sphere Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The second order Polarization mode dispersion of single mode fiber of 75 km is measured with Poincare spheré method, the statistical characteristics and influence of the components of the second order polarization mode dispersion (SOPMD) is analyzed. The parallel component and perpendicular component (also is callThe second order Polarization mode dispersion of single mode fiber of 75 km is measured with Poincare spheré method, the statistical characteristics and influence of the components of the second order polarization mode dispersion (SOPMD) is analyzed. The parallel component and perpendicular component (also is called depolarization component) of SOPMD and PCD are analyzed, and the statistical properties of them are also analyzed. According to these it is found that the perpendicular component has a greater impact on pulse than that of the parallel component in mean. The research will be helpful for second order PMD compensation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 583 (2004)
Fly Eye Lens Array Used in Liquid Crystal Projection Display with High Light Efficiency
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Illumination system is a main part in liquid crystal projection display system, and is important to color fidelity and other performance of a projector. As for fly eye illumination system, the light efficiency would be dramatically increased, if the fly eyes lenses are well designed. Two designs of the fly eye lenses aIllumination system is a main part in liquid crystal projection display system, and is important to color fidelity and other performance of a projector. As for fly eye illumination system, the light efficiency would be dramatically increased, if the fly eyes lenses are well designed. Two designs of the fly eye lenses are introduced on basis of the analysis on liquid crystal projection displays. The sub-fly eyes in both designs are all rectangular, so they are easy to design and manufacture. The light efficiency could be increased by decentering the sub-fly eyes and changing their shapes. By simulation, the light efficiencies of these two designs are increased by 16.5% and 26.3% respectively. The illuminating light on liquid crystal panel has good uniformity. In the end, two designs are compared with each other..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 587 (2004)
Fresnel Diffraction of the Grating Illuminated by Partially Coherent Light
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Fresnel diffraction of the grating illuminated by partially coherent light is analyzed based on the propagation of the mutual intensity in theory of partially coherent light. The general formulas of the intensity in the Fresnel diffraction field are obtained. Then the characteristics of the field diffracted by the The Fresnel diffraction of the grating illuminated by partially coherent light is analyzed based on the propagation of the mutual intensity in theory of partially coherent light. The general formulas of the intensity in the Fresnel diffraction field are obtained. Then the characteristics of the field diffracted by the grating is discussed in detail. Experimentally, the diffraction intensity of the grating illuminated by the light source (LED) with different illuminant area is measured in the Fresnel region respectively. Thus the basic characteristics and general rules of the grating diffraction are proved, for instance, the smoothness process of the source on to the diffraction intensity, namely, Talbot imaging, and the condition of gaining exact Talbot imaging. The experiment results conform to the theoretic ones very well.
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 692 (2004)
The Affect of Light Multiple Scattering on Particle Sizing by Using Light Extinction Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By using Monte Carlo method, author present an exact prediction of light transmittance in multiple scattering condition for different configurationBy using Monte Carlo method, author present an exact prediction of light transmittance in multiple scattering condition for different configuration.
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 696 (2004)
Quantum Optics
Dynamical Behaviors of Two Electrons Confined in a Line Shape Coupled Three Quantum Dots Driven by an AC Electric Field
[in Chinese], and [in Chinese]
With the three-site Hubbard model and Floquet theorem, the dynamical behaviors of two electrons confined in a line shape coupled three quantum dots driven by an AC electric field are investigated. The Hamiltonian contains no spin-flip terms, so the singlet and triplet sub-spaces are completely decoupled and can be analWith the three-site Hubbard model and Floquet theorem, the dynamical behaviors of two electrons confined in a line shape coupled three quantum dots driven by an AC electric field are investigated. The Hamiltonian contains no spin-flip terms, so the singlet and triplet sub-spaces are completely decoupled and can be analyzed separately. The analysis indicates that the nine-dimensional triplet sub-spaces can be divided intos three-dimensional sub-spaces with the same direction of spin respectively, and the dynamical behaviors in each three-dimensional sub-space are similar to that of two-electron singlet state in coupled two-quantum dots driven by AC electric field. In the six-dimensional spin singlet sub-space, the calculations show that, for certain combination of frequency and strength of applied AC field, the tunnelling between various configurations can be strongly quenched. Specially, two electrons localized initially in one quantum dot can hold on for a span of time. Using the perturbation approach to solve the Floquet function leads to a detailed understanding of this effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 700 (2004)
Propagation of the Transverse Separable Atom Laser Beam
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The propagation of the atom laser beam with non-conservation quality factor is discussed based on the theory of ABCD formulation of propagation of a time-dependent quantum system. The equation for the quasi-continuous atom laser beam wave-function is given by Schrodinger equation, the beam width, divergence curvature rThe propagation of the atom laser beam with non-conservation quality factor is discussed based on the theory of ABCD formulation of propagation of a time-dependent quantum system. The equation for the quasi-continuous atom laser beam wave-function is given by Schrodinger equation, the beam width, divergence curvature radius and quality factor were introduced to represent the atom laser beam whose transverse potential could be separated. For the conservative quality factor system in some direction, the propagator of ABCD formulation can be got. The propagation of the atom laser beam is discussed during the interacting with Bose-Einstein condensation (BEC), the propagation with the trap on and the free propagation with the trap off whose potential can be separated by x and y. Authors′ methods and results are compared with Yann′s..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 705 (2004)
Spectroscopy
Atomic and Ion′s Light Emission Spectra Induced by the Impact of 126Xeq+ on Al Solid Surface
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The measurement of light spectrum with wavelength from 200 nm to 1000 nm emitted from solid surface of Al which is excited by slow highly charged ions 126Xeq+ (6≤q≤30) is reported. The result shows that the characteristic spectral lines from transitions between complex configurations of atoms and ions can be effectivelThe measurement of light spectrum with wavelength from 200 nm to 1000 nm emitted from solid surface of Al which is excited by slow highly charged ions 126Xeq+ (6≤q≤30) is reported. The result shows that the characteristic spectral lines from transitions between complex configurations of atoms and ions can be effectively excited by the impact of highly charged ions on a solid surface even though the ionic beam is very weak. The relative intensity of those spectra can be enhanced sharply and greatly if the stripped charge q of incident ions (q) is beyond a critical value (q=26 for Al). According to the classic over-barrier modek, electrons captured and transferred play key roles in interaction between highly charged ions and solid surfaces if the kinetic energy of the incident ions is small (～1 keV/u). The ability of ions capturing electrons can be intensified by increasing charged states of the incident ions, therefore, the light spectra intensity of excited particles can be enhanced significantly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 713 (2004)
Resonance-Enhanced Multiphoton Ionization Spectrum of NO by C2Π←X2Π Transition
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Resonance enhanced multiphoton ionization (REMPI) spectrum of NO in the region of 490～580 nm is gained by using optical Parametric oscillator and Amplifier (OPO and OPA) as radiation source. The OPO/OPA is pumped by a Nd∶YAG laser. The spectrum is composed of regular band progressions. In comparision of the results of Resonance enhanced multiphoton ionization (REMPI) spectrum of NO in the region of 490～580 nm is gained by using optical Parametric oscillator and Amplifier (OPO and OPA) as radiation source. The OPO/OPA is pumped by a Nd∶YAG laser. The spectrum is composed of regular band progressions. In comparision of the results of theoretical calculation with the experimental ones, the peaks of the spectrum are attributed to the C2Π←X2Π transitions. The ionization pathway can be shown as NO(X2Π)hνNO(C2Π)2hν (or hν)NO++e. this conclusion is further verified with the near quintic variation of the ionization signal versus laser intensity. The possible reason that the distribution of the spectral intensity does not follow Franck-Condon principle is analyzed and discussed. The molecular constants about NO(C2Π) state are calculated based on the experiment. The results are e=(2354.9±6.4) cm-1, ee=(14.7±2.5) cm-1 and force constant k=(2.44±0.08)×103 N?m-1. The conclusion can provide reference for the detection of pollutant NO..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 24, Issue 5, 718 (2004)
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