The residual error of adaptive optical system based on stochastic parallel gradient descent control algorithm is analyzed. The relation between steps of iteration and control numbers is specified by numerical simulation of correcting static aberrations. Simplified control model for adaptive optical system based on stochastic parallel gradient descent algorithm is introduced. Analytical expression for the relation between residual error and convergence time is deduced. The residual error is analyzed by using the temporal power spectral density of the atmospheric turbulence. It is revealed that if dynamic atmospheric turbulence with a Greenwood frequency fG is to be corrected using a N-element adaptive optical system,the iteration rate should be greater than 86 NfG to ensure the residual error corrected is less than λ/10. It is also pointed out the limited range of adaptive optical system based on stochastic parallel gradient descent control algorithm from a typical computing result.

The reflecting matrix,transmitting matrix and internal radiation source function vector of the rough sea surface were deduced in detail,and were applied to the vector radiative transfer numerical model of the coupled ocean-atmosphere system named PCOART. The model was validated by the two rough sea-surface radiative transfer problems,one was the vector radiative transfer problem of the Rayleigh atmosphere,and the other was the radiative transfer problem of the coupled ocean-atmosphere system. The result shows that the model gives accurate simulation for the two aspects,especially with the relative error of Rayleigh scattering radiance less than 0.5%. Compared with the existing scalar radiative transfer numerical model of the coupled ocean-atmosphere system,this model can derive the radiance field and the Stokes vector field for the whole ocean-atmosphere system.

In order to provide a quantitative evidence that confirms the error source and reduce the retrieved error in the retrieved model of water color,transmissivity,parameter of Gordon model,bidirectional factor under the different conditions of environment and water quality are simulated based on the software of optical radiative transfer model HYDROLIGH. The interactions of wind speed,solar zenith and single reflectivity to T,f,Q and f/Q are analyzed,the primary influecing factors of T,f,Q and f/Q are determined. The primary influencing factor of T,f and Q is solar zenith relatively,the influences of single reflectivity and wind speed to T,f and Q are much smaller. The leading influencing factor of f/Q is single reflectivity,the second is solar zenith,and the third is wind speed,the interaction among the influencing factors is much stronger. The influence of Raman scattering on T,f and f/Q can be neglected in the high-scattering water. The effects of colored dissolved organic matter (CDOM) and chlorophyll′s fluorescence on f and f/Q are decreasing with the increase of concentration of CDOM and chlorophyll,but the effects cannot be ignored in eutrophic water body with high concentration of CDOM and chlorophyll.

Phase-shifted long-period fiber grating (PS-LPFG) with film coating can improve the filtering characteristics of fiber grating due to its flexible structure and design. Based on transfer matrix method,the filter characteristics of PS-LPFG with film coating inserted by one phase-shift at different position or many π phase-shifts are analyzed. The results show that two new stop-bands appear at both sides of the resonant wavelength when a single π phase shift is inserted,and the interval of the two stop-bands increase with the number of phase-shifts inserted. Further studies indicate that the film thickness can adjust flexibly the location and amplitude of the loss peak. As the film thickness increases,the two loss peaks shift toward the shorter wavelength. When the film thickness increases to a certain value,the loss peaks jump to the longer wavelength,and meanwhile,the amplitudes of the loss peaks decrease rapidly. Subsequently,the loss peaks shift toward the short-wave direction again and the amplitudes increase with the film thickness. In addition,the changes of longer wavelength peaks lag behind the shorter wavelength peaks.

A novel tunable wavelength filter is designed and demonstrated,which is realized by bending a fiber Bragg grating (FBG) mounted on a two-fixed-end elastic compressive bar. According to material mechanics,equations relating the wavelength tuning of FBG to the bending strain are derived. The resonant peaks during tuning process are simulated and analyzed in detail. FBG wavelength tuning experiments are carried out by using self-designed tuning apparatus. The wavelength change has a strictly exponential relation with the displacement of the translation stage. The experimental tuning range is greater than 35 nm and the 3 dB bandwidth change is less than 0.09 nm. The tuning has a repeatability with hysteresis of 0.08%.

By introducing the grating refractive modulation into the evanescent field coupling,the unified coupled-mode equation for all kinds of fiber grating filters written in fiber coupler is obtained,which parameters have specific physical meaning. The filtering response of three kinds of fiber grating filters written in fiber coupler are analyed by numerical methed of Broyden and shooting. The influences of relative parameters on the filtering response characteristics are investigated theoretically. Drop channel efficiency of 95%,85% and 99% can be obtained for grating assisted coupler,grating reflection coupler and grating frustrate coupler by optimizing parameters. Grating assisted coupler and grating reflection coupler are fabricated with reflectivity 15 and 18 dB.

For standard single-mode optical-fiber Brillouin scattering light,its frequency shift is a function of temperature or strain. So,the temperature or strain of the optical-fiber can be obtained via detecting Brillouin frequency shift. However,Brillouin scattering distributed optical-fiber sensor (DOFS) has two structures of optical time-domain analyzer and optical time-domain reflectometer. These two DOFS structures have their respective performance and application. It is necessary to select either optical time-domain analyzer or optical time-domain reflectometer for the real application,in order to achieve effective distributed sensing. As for the combination of these two structures in one sensing system by using the same optical devices,the key point is to produce the frequency-shifted reference or probe light. A fiber laser is employed as one optical source,a microwave electro-optical modulator is used to produce the frequency-shifted reference or probe light,and a method named with the orthogonal polarization control is adopted to reduce the effect of the optical-polarization-related problem. A laboratorial system of 25 km distributed optical sensor is realized by combining these two structures,with 3 ℃ in temperature resolution,and 5 m in spatial resolution.

Fluorescence optic-fiber temperature sensor based on Planck law is studied by using sapphire fiber as thermal probe. With a high melting point,over 2000 ℃,high transmissions in the wave band of 0.3-0.4 μm and favorable mechanical and chemical inert,sapphire fiber is very attractive for high temperature optical fiber sensor and near infrared energy delivery. The measured fluorescence life time can be obtained by calculating tangent value of first non-zero phase angle and using fast Fourier transform to measure the life time of fluorescence. This method has virtues such as fast speed,small error and no background interference. In the detection range from 0 to 450 ℃,the thermometer has an average temperature resolution of 0.4 ℃. The experimental results show that this system can effectively decrease the influence of instability of light source and intensity variation in measuring channel on results. The system has advantages of high accuracy,very high temperature resolution,good dynamic response and immunity to the electro-magnetic interference.

A new architecture of access network based on slotted optical code division multiple access (OCDMA) packet passive optical network (PON) is proposed. The random access protocol based on this network is presented,and the bit-stuffed unipolar m-sequence is used as the address code. Next,mathematic model of the network throughput of the passive optical network under the given protocol is derived. The throughput performance is numerically investigated. Theoretical analysis and simulation results show that the proposed slotted OCDMA packet network obtains a better network performance. The network throughput will be deteriorated by reducing the received optical power or increasing the multiple access interference. But the throughput decreases as the received power decreases when the offered traffic becomes larger. By reducing the packet length,the network throughput will be improved.

A holey fiber with beat length independent of wavelength is designed by combination of two defect structures respectively with positive and negative birefringence. The radius of a pair of air holes adjacent to the core is enlarged and the other circular air holes in the cladding are substituted with elliptical holes at the same time. Birefringence with different signs generated by these two changes may interact with each other so that the beat length is less sensitive with wavelength. Finite-difference beam propagation method (FD-BPM) is used to calculate and analyze the influence of different structural parameters on birefringence of holey fiber. Stable beat length can be achieved at some wavelength window by adjusting the structural parameters and the value of the beat length can also be tuned according to practical requirement. Uniform beat length with more than 180 nm bandwidth at 1310 nm wavelength window is obtained by optimizing structural parameters of holey fiber.

We report the experimental progress of the timing distribution system with a femtosecond laser. For the pulses at repetition rate of 89.7 MHz from a femtosecond fiber laser as the timing signal,and with an active variable timing delay line,we reduced the timing delay from 180 ps to 36 ps,by comparing the phase of the 10th hamonic repetition rate of the fiber laser with the feedbacked pulse signal. The results proved the technique to be effective for delay compensation in a timing distribution system. The theoretical prediction of the resolution of the sysytem should be in the order of 10 fs. The noise makes the actual resolution greater than 10 fs. Further experiment is going on to improve signal-to-noise ratio and the the system stability.

The hybrid transmission of 42.8 Gb/s differential phase shift keying (DPSK) and of 9.95 Gb/s on-off keying (OOK) signals is experimentally demonstrated. The length of fiber loop is 410 km. The transmission line consists of four spans,each including standard single-mode fiber (SSMF) and dispersion compensation fiber (DCF). The signals are amplified by both erbium-doped fiber amplifier (EDFA) and distributed raman amplifier (DRA). The 42.8 Gb/s DPSK signals is detected by single-ended detection. The optical power spectrum,eye diagram and the curve of bit error rate (BER) are given,both in single-channel transmission 410 km and in hybrid transmission 410 km.

The mechanisms for improving the gain properties of the forward- and backward-pumped L-band double-pass erbium-doped fiber amplifiers (EDFA) are experimentally investigated. The gain enhancements of the two EDFA are compared for different EDF lengths. The results show that,the gain improvement mechanisms of the two pumping schemes are different. With the forward-pumped scheme,the population inversion near the signal input (output) port is very high,which helps to amplify the L-band input signal quickly after entering the EDFA and boosting its power before being exited. Such high L-band signal power near the signal input port may in turn suppress the backward C-band amplified spontaneous emission (ASE) near the input pump port,and thus,improve the L-band gain properties. With the backward-pumped scheme,the backward C-band ASE generated in the pump input port may be reused as an auxiliary pump source to enhance the L-band gain. However,for the backward-pumped scheme,the reuse of the backward C-band ASE may cause the gain self-saturation effect due to the high ASE level. It is found that the gain improvements of the EDFA with forward pumping scheme is slightly better than those with backward pumping when the EDF length is 20 m,because of the gain self-saturation effect caused by the high ASE. However,when the EDF length is more than enough for pump absorption,compared with the backward-pumped scheme,the forward-pumped L-band double-pass EDFA exhibits obviously insufficient pump,deteriorating its gain improvement,especially for the relatively low input signal power.

According to special requirement of seepage monitoring in engineering and model experiment of dams,tunnels and coal mines,a novel optical fiber Bragg grating (FBG) based seepage pressure sensor is designed and fabricated. A draw-bar structure and a corrugated diaphragm are adopted to change the axial strain of optical fiber grating. The diaphragm pressure characteristics and sensor′s shell resistance characteristics are simulated and analyzed by using the finite element software ANSYS respectively,which can shorten the design cycle and improve the reliability of the sensor. Calibration experiments show that the pressure sensitivity of the sensor is 20 nm/MPa in the range of 0-100 kPa,which is 6683 times higher than that of ordinary optical FBG. The hysteresis and repeatability experiments indicate that the hysteresis factor is 0.85% and the sensor has good reproducibility.

We report on a single-frequency polarization maintaining (PM) ytterbium-doped fiber (YDF) amplifier by using a single-frequency Nd:罽VO4 oscillator seed source and a large-mode-area panda polarization maintaining fiber. The system generates single-frequency radiation up to 17.3 W at 1064 nm wavelength with 62.8% slope efficiency,57.6% optical-optical power conversion efficiency and the polarization extinction ratio is better than 24.3 dB. The spectral characteristic,output power characteristic and polarization characteristic of the single-frequency PM YDF amplifier are discussed in detail.

The Runge-Kutta ray tracing method is introduced firstly,which is used as a basic ray tracing method for the medium of the discretionary refraction index distribution. Then towards the three-dimensional fluid field with the characteristic of discrete refraction index distribution,a numerical computation method of any point′s refraction index and gradient is proposed. During the process of ray tracing,an idea and method that tracing step distance is self-adaptive according to local refraction index gradient and grid geometry scale are carried out,which can improve the tracing precision and efficiency. The results show that the method has high precision and efficiency for the ray tracing of three-dimensional space with the discrete refraction index distribution.

A new method of getting transformation among two images by feature point matching was proposed to match the serial dynamic images fast and exactly. First,in the light of multiple restriction (MR) criterion,including local information entropy,similarity measure and criterion of constant distance scale,three pairs of matched points were found exactly between two images. Then,using the points,six affine parameters of two images were computed by matrix LSM. Experimental results indicate that compared with correlation method,MR algorithm can wipe the false matching points off resulting from the movement of object. Aiming at 384 pixel×256 pixel images,only 2.76 ms is needed for MR algorithm to complete feature points matching. 58% time was reduced. And the error of affine parameters estimating in X,Y direction,was cut down to Δx=0.13,Δy=0.02,greatly less than one pixel. This method can meet the needs of high speed,precision and adaptability in engineering field.

To match reliably point pairs,a matching algorithm based on the probabilistic relaxation of the spectral correlation is proposed. Firstly,the initial matching probabilities are obtained from the shape context of the two point sets. Then,two proximity matrices are defined from the point sets respectively,and the spectral correlation of the matrices as the initial support is acquired by the singular value decomposion (SVD). Finally,the matching of the two point sets is implemented by using the method of probabilistic relaxation. Experimental results show the high accuracy of the algorithm.

A fuzzy evidence combination method based on square evidence weight is proposed,and it is used in the dim target multi-feature fusion detection. The basic probability assignment function of the evidence is used to express decision result′s uncertainty. First the detection image′s four features,which are local gray average contrast,local gradient average contrast,local variance and local entropy,are picked up and normalized,then after defuzzification of features,the basic probability assignment of target′s features with supposed set of recognition target can be got according to a priori knowledge and statistical result. After getting basic credibility using adaptive weighted fusion rule it can get the detected target image by decision making rule of game probability distribution. The experimental results show that the method can reduce the uncertainty during the target detection to a large degree and improve the target detection performance of the whole system.

A novel method for the three-dimensional (3-D) object recognition based on modulation analysis is proposed. Two orthogonal gratings with equal interval are vertically projected on an object surface,and the measured object is placed between the focusing planes of the two gratings. Then the image of orthogonal grating modulated by the object height can be obtained by a CCD camera from the same direction,and the object height information is encoded in this image. They are processed by the operations consisting of performing the Fourier transform,spatial spectrum analysis,so the fundamental spectrum in two directions can be obtained. Then the recognition parameter (the sum of the intensity of each fundamental spectrum) is calculated. The values of recognition parameter are treated as a point in the recognition space. If the shape of object is different,the values of recognition parameter are also different. The different objects will be shown in the different positions because of the deference of the values of recognition parameter. Both computer simulation and experimental results are presented in support of the proposed idea.

In order to obtain a correct phase unwrapping (PhU) result,as well as to alleviate the effect of noise,a novel quality map is proposed. Firstly,some disadvantages of phase derivative variance (PDV) quality map and modulation map are analyzed. Then based on isotropic gradient amplitude,some methods about image sharpening and modulation are combined to construct a new quality map. The new map is named “Modulation-Roberts Gradient Amplitude Variance” quality map (MRGAV). In the applications,the computer simulated and the experimental data are offered. The comparison between the MRGAV quality map and the PDV quality map shows that the MRGAV quality map is not only more reliable,but also can overcome the drawbacks of the PDV and some other traditional quality maps successfully.

A method for phase extraction of an electronic speckle pattern interferometry (ESPI) fringe pattern based on two-dimensional (2D) continuous wavelet transform is presented. The phase of the fringe pattern is retrieved by detecting the 2D-wavelet ridges. By using a scanning strategy guided by the fringe frequencies,the problem of sign ambiguity could be avoided. The algorithm can deal with open-fringe patterns as well as closed-fringe patterns and it has a strong ability of speckle noise immunity. Simulation and experimental results show that the phase of the ESPI fringe patterns (open-fringe patterns or closed-fringe patterns) can be extracted successfully.

To investigate the influence of atmospheric turbulence on the image ofsynthetic aperture ladar (SAL),numerical simulation of phase screens following the Kolmogorov spectrum by using spectrum inverse transform is introduced and detailed pictures of monolayer or multilayer random phase screens are given,then the calculated multilayer random phase screens are used to simulate the real atmospheric turbulence. In an ideal monostatic airborne spotlight SAL imaging system,detailed calculations on the SAL images with point or extended targets through no,weak,medium and strong turbulence are illustrated. The results vividly show that the atmospheric turbulence can severely affecte the azimuth resolution of the SAL image and with the increase of the atmospheric turbulence,the distortion of the SAL image deteriorates. To correct the degraded SAL images induced by atmospheric turbulence,phase gradient algorithm (PGA) method is implemented in azimuth,and the effort shows a significant improvement in the guality of the SAL image.

Theoretical analysis and simulation were made for near-field small system imaging of reflective tomography laser radar. In the Rayleigh-Sommerfeld diffraction domain,wavefront of the target belongs to spherical wave diffraction. According to Nyquist criterion,the constraints including the number of sampling angles and the number of sampling points in each projection for spherical wave reflective tomography were obtained. Broken lines method was introduced to avoid square and extraction operation and shorten imaging time. The simulation results show that double broken lines method was effective in solving the computational complexity problem in image reconstructed. Also with the increasing distance between the detector and the target,images reconstructed by the double broken lines method are close to the reference image.

The imaging performance of spiral zone plates is studied. Spiral zone plate is a new imaging optic device which can implement optical Hilbert transform and produce the edge-enhanced imaging of an object,is presented. The performance of spiral zone plates is numerically analyzed using fast Fourier transform and the working condition of spiral zone plates is studied by the numerical calculation. It is generally considered that the distance between the object and the optics should meet the Fraunhofer diffraction using the spiral zone plate as the spatial filter. The numerical analysis shows that the spiral zone plate still works well in some Fresnel diffraction region. It means that the actual field of view is larger than that restricted by the Fraunhofer diffraction. The experimental results show good agreements with theoretical simulation. The method of fast Fourier transform can effectively evaluate the imaging performance of spiral zone plates and provide an important guide to the design of the spiral zone plate microscope.

The phase errors due to the nonlinear chirp of a tunable laser reduce the range resolution in synthetic aperture imaging ladar (SAIL). The compensating algorithm was developed. The estimation errors of the phase shifting function and the compensation errors of the traditional compensation algorithm must be eliminated. The theoretical derivation of the practical phase shifting function for finite data in practical application is established and the reason for the transfer errors of the theoretical phase shifting function is analyzed. The simulation model of the airborne SAIL working in strip map mode is established,and the simulation validates the derivation results. The method for reducing errors in the nonlinear chirp compensation algorithm is given finally.

To analyze the photometric characteristics of medium and high apogee satellites based on light reflection model,visual band time series photometry of satellites are employed for studying their physical properties. A sample of satellites in different shape,technical status and stabilization is composed. The accurate time series observations and distance correction method,phase angle calculation method are presented. First,mirror-reflection and diffuse of sunlight on spherical bodies and more complicated shapes are observed and analyzed. Then,experimental results showed that time series photometric light curve can reveal satellite′s physical characteristics,such as shape,stabilization and health status. It can provide the criteria to determine the technical status and the evolvement of satellite.

The sources of stray sight of space-based infrared detecting system are studied. They are analyzed and calcuated by use of blackboby radiation. The irradiance of the focal plane which arises from earth and atmosphere is analyzed by model established in TracePro. The projected solid angle subtended by the surface of earth and atmosphere to the camera can be known by the method of ray-tracing. The method makes the complex calculation become easy. Then the noises of detecting system are analyzed. The noise-equivalent-irradiance (NEI) of a certain Sofradir infrared-focal-plane-array is calculated and compared with irradiance induced by other stray lights. The result proved that the irradiance of the focal plane which arises from stray light is far bigger than the NEI of the infrared-focal-plane-array. Methods should be adopted to suppress stray light. The demand of rejection of the stray light from earth and atmosphere and the demand of the temperature of optical system are given. This result can be a reference for system design.

Based on the Kirchhoff's law,an experimental apparatus for emissivity measurement at intermediate and high temperatures is developed,in which the double-light-path contrast measurement technique is used. The apparatus consists of three parts:the sample heating system,the signal detection and processing system,and the display system. With this apparatus,the emissivities of two standard samples (polished steel and roughened steel) are measured at different temperatures. The emissivity data of these two samples are fitted to the analytical function with the least-squares method. The measurement uncertainty of this experimental apparatus is analyzed. As a result,over the temperature range from 800 K to 1100 K,the largest emissivity uncertainty of the polished steel is σε=4.26×10-3,and the corresponding uncertainty of temperature measurement is σT=0.497 K,σT/T=0.0611%;the largest emissivity uncertainty of the roughened steel is σε= 3.80×10-3,the corresponding uncertainty of temperature measurement is σT=0.415 K,σT/T= 0.0507%.

A 10 Gb/s optoelectronic integrated circuits (OEIC) optical receiver front-end has been studied and fabricated based on domestic material and semiconductor process. A limiting amplifier (LA) has been designed and realized by using depletion mode pseudomorphic high electron mobility transistor (PHEMT). The OEIC optical receiver comprises a metal-semiconductor-metal (MSM) photodetector and a current mode transimpedance amplifier (TIA),and a device model has been established and optimized by simulation software SILVACO. The photodetector has a photosensitive area of 50 μm×50 μm,a bandwidth of 10 GHz and a capacitance of 3 fF/μm. The etch-stop process has been developed completely and applied to the fabrication of OEIC device,and the chip has an area of 1511 μm×666 μm. The bandwidth of LA is expanded by inductance which has been simulated by software HFSS. The chip area is 1950 μm×1910 μm and the measured results demonstrate a transfer rate of 3.125 Gb/s (10 and 500 mV) with constant output swing 500 mV.

The delay time response function of the waveguide microring resonator is deduced from its optical-field transmission function. The influence of microring waveguide loss on the delay time characteristics is analyzed and the result shows that the microring resonator-based optical delay line applied in the optically controlled phased array antenna system should be at over-coupled condition,which means that the coupling coefficient κ and the microring waveguide loss factor γshould satisfy the relation of κ>(1-γ). According to the criterion of delay time ripple guality factor ε,the method of optimized design of the microring resonator-based optical delay line is established,and the optimized structural parameters of cascaded four microring resonators for target delay time of 0.6 ns,bandwith of 2 GHz,and delay time ripple guality factor less than 1×10-3 ns2 are obtained.

The intensity-dependent loss output characteristic of the symmetric nonlinear optical loop mirror (NOLM) can be induced by the nonlinear polarization rotation effect. The application of symmetric NOLM as the intensity equalizer to suppress the mode competition in multiwavelength eribum-doped fiber laser is studied. The influences of both input polarization and birefringence on the output characteristic are analysed. The polarization conditions in this laser cavity are analysed. A multiwavelength eribum-doped fiber laser with this device is porposed and demonstrated successfully. In the L-band 13 lasing wavelengths,with 1nm spacing in 3 dB range,has been obtained,single-wave length power fluctuation of each laser line is less than 0.6 dB within 0.5 h. Both the laser line number and its multiwavlength operation spectral region can be controlled by adjusting the intensity-dependent loss in the cavity.

The single-frequency Nd:YVO4 laser with a CW laser-diode single-end-pumped is described. Under stablecavity condition basing on heat lens,the relation of beam radius versus pump average radius in the crystal center is analyzed in a simple bow-tie ring cavity configuration. When the incident pump power is 30.3 W,a 1064 nm single-frequency laser,with its output power of 10.48 W(line-polarization power 10.02 W),is obtained. the optical-optical efficiency is about 34.6% with beam quality is M2X=1.18 and M2Y=1.19. The fluctuation of laser frequency is about 70 MHz in a minute. The fluctuation of power is about 0.5% for four hours.

By simultaneously using both active and passive Q-switched in the same cavity,a diode pumped doubly Q-switched c-cut Nd:GdVO4 laser was realized with acoustic-optic (AO) modulator and Cr4+:YAG saturable absorber. The technique to control the pulse duration has been studied. With varying the positions of the saturable absorber and the modulator,the pulse durations are varied,respectively. The average output power,the pulse duration and the peak power versus the position were obtained. Using the ABCD matrix method,the intracavity radii along the cavity axis were calculated. Mean while,a rate equation model is introduced to theoretically analyze the results obtained in the experiment,in which the Gaussian spatial distribution of the intracavity photon density and the AO turnoff time including the transit time are taken into account. The numerical calculations of the rate equations,are consistent with the experimental results.

Many factors of intracavity perturbation degrades the output power and beam quality for high power laser diode pumped solid laser. Firstly,the relation between the focal length of thermal lens and the beam spot size is analyzed by means of transmission matrix optics. Experiment on output beam quality of a LD pumped acousto-optic Q-switched laser has been also performed by adopting Hartmann-Shack wavefront sensor and mode method of wavefront reconstruction theory. Using this method,the peak-to-valey value and root mean square values of the aberration wavefront,the frontal 35-order Zernike aberrations can be acquired,and Strehl ratio curve of the output beam and the distribution of circle energy can also be obtained by calculation,so the mode properities can be fully understood. Experimental results show that the beam wavefront aberration is mainly concentrated in the frontal 15 orders of Zernike aberration,mainly including the defocus Z3,the low-order astigmatism Z4 and Z5,and the spherical aberration Z10 because of crystal thermal effect.

The spectrum of XeF laser has been studied using two kinds of resonator mirrors. Two kinds of lasers on B-X and C-A transitions can be obtained under the same experimental condition. The formation time of the XeF(B-X) laser is 800 ns earlier than that of the XeF(C-A) laser. The influence of the original XeF2 concentration on XeF laser spectrum is studied in detail. The experimental results indicate that lower original XeF2 concentration impedes the formation of the XeF(B-X) laser. With the XeF2 concentration increasing,the XeF(B-X) laser presents the characteristic of a series of discrete line spectrum. The spectra of XeF(C-A) laser using two kinds of resonator mirrors are given. The XeF(C-A) laser spectrum is characterized by a continuous broadband spectrum and the absorption lines of atomic Xe can be observed in the spectrum. The narrow band XeF(C-A) laser can be obtained with the appropriate resonator mirrors. The bandwidth of the narrow band XeF(C-A) laser spectrum is 7 nm.

The positive-negative circularly polarized four-frequency differential laser gyro (PNDLG) is a novel four-frequency differential laser gyro,it has no optical element except the reflecting mirrors in the cavity,its operating modes are elliptical polarization modes. For the study of PNDLG operating characteristics,the vector self-consistency equations of PNDLG are presented with the elliptical polarization eigenvector mode. Based on the Lamb semi-classical self-consistency field theory,the Lamb coefficients of elliptical polarization modes arederived from the motion equations of the density matrix with the third-order perturbation method. The analysis shows that,Lamb coefficients of elliptical polarization modes can be obtained by those of circular polarization modes multiplying the corresponding ratio,the ratio is the square of the proportion of the positive negative circular polarization electric field component to the whole elliptical polarization electric field amplitude. Finally,the vector self-consistency equations of the PNDLG are built up and proved to be effective by the preliminary experiment,which is useful for the theoretical research on the PNDLG.

It is impossible to measure the M2 factor of pulsed laser effectively by using the traditional equipment. For real-time measurement of the M2 factor,two crossed defocus gratings and a lens with short focal length are used to obtain nine beam spots of different positions. The value of M2 factor is determined by calculating the beam waists using the second-moment method and curve-fitting. According to the theory of Gaussian beam propagation and transformation,measured errors as functions of beam waist and positions are analyzed. The analysis shows that the measuring system can work well in a large range. The pulse-to-pulse M2 factors and the change of M2 factors along with the pumping voltages of the 1064 nm Nd:罽AG pulsed laser are measured. The results indicate that measurements of M2 factor of pulsed laser are realized and the system can work successfully for measuring changes of M2 factors during laser working in real time.

Based on the method of Collins diffraction integral formula and expanding the rectangular function into a sum of complex Gaussian functions,the effect of smoothing by spectral dispersion (SSD) considering the hole size used in spacial filter is studied,and the method of the selection of hole size in view of aberration is given in the article using the statistical optics model raised by K.R.Manes et al.. Numerical simulation show that the holes now used in experiment are small for SSD,fluence beam contrast without holes raise from 22％ to 36％,and calculate the needed pinhole size for SSD.

Multi-wavelength narrow linewidth lasers can greatly reduce the cost for light sources used in dense warelength division multi-plexing (DWDM) optical network node equipment. A way to achieve it by an active fiber ring resonator incorporating an optical phase modulator is proposeed. Its output power is stable because there is no mode competition in it. Hundreds of laser wavelengths can be achieved when the frequencies of input laser and radio frequency modulation signal coincide with the frequency of the resonator′s longitudinal mode. The expression of the multi-wavelength laser is derived. Computed results show that the relative total output and the single-wavelength relative output are related to modulation depth of phase modulator and coupling coefficient of the input/output coupler. The coupling coefficient below 0.9 and the phase modulation depth above 2.0 rad benefit stability of output power. Total output and single-wavelength output power can reach several hundreds milliwatt and milliwatt levels. Theoretical analysis and calculations show the linewidth of any laser wavelength in the multi-wavelength laser is about equal to that of input laser when the circulating time inside the resonator is not much larger than coherent time of input laser.

Monodispersed spheres for Tb3+-doped BaWO4 phosphors are synthesized by a hydrothermal method. X-ray diffraction (XRD),and field-emission scanning electron microscopy (SEM),energy dispersive spectrometer (EDS) are used to characterize the resulting samples of crystal phase structure,particle size and morphology and composition. Photoluminescence excitation and emission spectra and decay curve are used to characterize the fluorescence properties of phosphors. XRD analysis confirms the formation of BaWO4 with scheelite structure. SEM study shows that the obtained BaWO4:Tb phosphors of different Tb3+ concentrations appear to be dispersed spheres and their particle sizes range from 2 to 4 μm. Analysis of the photoluminescence spectra with different Tb3+ concentration reveals that the optimum dopant concentration is about 12% of Tb3+ions in BaWO4:罷b phosphors. Photoluminescence spectra indicate the phosphors emit strong green light centered at 545 nm under 254 nm UV light excitation in comparison with the commercial green fluorescent lamp phosphor (LaPO4:罜e,Tb). The results shows that the intensity of BaWO4:罷b phosphors is comparable to that of LaPO4:罜e,Tb.The excellent luminescence properties make it a new promising green phosphor for fluorescent lamps application.

CaSi2N2O2 codoped with 2% Eu (fixed) and varying M concentrations (Gd:1% -12% ,Dy:0.25% -6%) for white LED are prepared by solid-state synthesis method. Crystalline phase is investigated by powder X-ray diffractormeter (XRD),and it is found That ,the Eu,M-codoped Ca1-ySi2N2O2 phosphors have the monoclinic structure. Excitation spectra and emission spectra are investigated by spectrometer. The results indicate that there is a broader emission band centered at 550 nm when excited by 380 nm,which was ascribed to the electronic transition of the Eu2+. Dy3+ and Gd3+ ions successfully play the role of sensitizer for energy transfer in the system. The addition of M remarkably enhances the luminescent intensity by the factor of 139% and 143% for Dy and Gd respectively. The luminescence mechanism of phosphors codoped with Dy3+ or Gd3+ ions is also investigated.

Yb3+:GdTaO4 was grown by Czochralski method. Its absorption,photoluminescence spectra were measured,and its spectral property parameters were computed. Full width at half maximum (FWHM) of absorption of Yb3+:GdTaO4 is 56 nm,which is 2.4 times broader than that of Yb3+:YAG. Its absorption peaks are at 930,957 and 974 nm,whose absorption cross sections are 0.81×10-20,0.91×10-20,and 1.2×10-20 cM2,respectively. The main peak of photoluminescence is at 1016 nm. The FWHM of emission peaking at 1016 and 1035 nm are 42 and 57 nm,which are 4-6 times wider than that of Yb3+:YAG,corresponding cross sections are 2.29×10-20 and 1.36×10-20 cM2,respectively,which are a little higher than or equal to that of Yb3+:YAG. Its broad absorption band makes for decreasing the dependence on the temperature control of pump laser diode (LD),and broad emission band makes for realizing laser output of ultra-short pulse and tunable laser. Results indicate that Yb3+:GdTaO4 is a very promising laser medium used in all-solid state ultra-short pulsed and tunable lasers.

The O2-PLS method was applied to basic research on non-invasive measurement of human blood glucose. The O2-PLS method can respectively divide the spectral matrix and concentration matrix into aim factors and aimless factors,only using aim factors to build calibration model. Two-component glucose solution,four-component glucose solution and human plasma samples are taken as research objects,and test set validation method is used to evaluate prediction results. The results show that prediction correlation coefficients are all 0.999 and root mean square errors of prediction (RMSEP) were 1.446,1.93,.274 mg/dL respectively. The prediction accuracy of O2-PLS models are higher than that of PLS models. Moreover,the complexity of samples has less effect on the prediction accuracy of O2-PLS models compared with traditional partial least squares (PLS) models. The experimental results indicate that O2-PLS method is applicable to complex samples detection.

A chaotic anti-control and synchronization method of mutual coupling between two degenerate optical parametric oscillators is present,based on the nonlinear dynamic characteristics of degenerate optical parametric oscillator. Transforming degenerate optical parametric oscillators from periodic state into chaotic output is simulated numerically. The lowest mutual coupling coefficient of degenerate optical parametric oscillator with different pump field amplitude is calculated. Numerical simulations show that there are different chaotic attractors depending on the different coupling coefficients and pump field amplitudes.Precise chaotic synchronization can be reached only if they have chaotic output. They realize identical synchronization or inversed synchronization because of different coupling types.

The characteristic of screening spatial solitons in two-photon photorefractive media is influenced by media temperature. The light and dark screening spatial soliton solutions derived from the evolution equation of spatial solitions are temperature-dependent. The intensity profile and the full width at half maximum (FWHM) of screening spatial solitons in two-photon photorefractive media are strongly influenced by the media temperature in the room temperature range. By raising the media temperature,the screening spatial solitons with low intensity are formed,and moreover,the light and dark screening spatial solitons with narrow FWHM are formed under the high light intensity case,and the light and dark screening spatial solitons with wider FWHM are formed under the low light intensity case. The self-deflection of bright screening spatial solitons in crystals strongly depends on the temperature,and the spatial shift of the beam center and the deflection angle all increase with the dropping of the temperature.

A rotate-in-group zoom optical system can realize dual/multiple field-of-view (FOV) switch,and according to its characteristics the relation of rotate-in-group lenses focus and system′s lenses spacing,focus,F number and magnification factor is retrieved. Rapid switch is achieved for a rotate-in-group zoom optical system when a narrow FOV subsystem changes to a wide one after a rotate-in motion of two negative-positive separated lens groups. Meanwhile,in the wide field mode,the FOV switch lens group is located outside the active narrow-field ray-bundle without intersection. The derived formula is proved by the design of a focal plane array-based midwave infrared rotate-in-group zoom optical system. The designed system has rapid dual/triplex FOV switch,limited lens number for narrow FOV subsystem,and large operation range,and meets the requirement of infrared search and track.

Cluster-cluster aggregation (CCA) model based on Monte-Carlo method is used to simulate the structure of the fractal-like soot clustered agglomerates consisting of spherical primary particles,and numerical calculations are carried out on laser scattering by randomly oriented soot clustered agglomerates based on the discrete dipole approximation (DDA) method. Comparison of the laser scattering properties between equivalent spherical particles and randomly oriented soot clustered agglomerates shows that the differences between them are obvious. The scattering properties on randomly oriented soot clustered agglomerates are determined by the radius and number of primitive particles besides the refractive index. This research will provide an effective theoretical approach for the research of formation mechanism,structural characteristics of randomly oriented soot clustered agglomerates and propagation property of laser in them.

Spontaneous radiation generated from an electron beam moving across a multilayer film is discussed. The precise wavelength formula of spontaneous radiation,the change law of electron beam quality and the radiant power of spontaneous radiation are analyzed. The results show that the electron numbers with diversified velocity is in accord with the exponential law with the increase of spontaneous radiation. The radiant power of a single electron bunch is in inverse proportion to the space cycle of metallic-dielectric multiplayer.

The investigation of laser bubble erosion through laser cavitation and high speed photographic to analyze the integration characteristic of bubble collapse is presented. The apparatus of laser bubble erosion measurement in the vicinity of a solid boundary is designed based on the laser cavitation. The laser bubble characteristics,such as collapse shock wave,rack of bubble wall and cavitation jet are measured based on the high-speed photography tiny adjustable machine,and the non-dimensional parameter γ is analysed. The results show the rigid boundary can delay the bubble collapse,and the actions of bubble shock wave and cavitation jet are competitive. The destructive effect of the second bubble collapse is stronger when bubble impulsion is near a solid boundary. The accretion of liquid viscidity can delay the bubble collapse,and the movement velocity of bubble skin is slowed down.

The three dimensional density distribution of a spin-polarized Fermi gas in a harmonic magnetic trap is calculated by using the Tomas-Fermi approximation. By fit the optical density distribution of absorption imaging,the total atom number,Fermi temperature and the actual temperature of the gas may be extracted. According this method,the optical density distribution of absorption imaging of degenerate fermions 40K in our experiment is fitted to obtain quantum degeneracy parameter T/TF of the Fermi gas.

Optical clock is reported that the capture of cold strontium (Sr) atoms in a magneto-optical trap (MOT) by using Zeeman slowing. The MOT is loaded from a thermal atomic beam which is decelerated by a Zeeman slower having 10.2 A electric current. The anti-Helmholtz coils of MOT have 10 A current and then can induce a linear magnetic field. Its gradient is 4 mT/cm in the central zone. The 461 nm laser is used for Zeeman slowing and trapping which corresponds to the transition of Sr atomic level (5s2)1S0→(5s5p)1P1 . According to the experiment,four isotopes of Sr in MOT are obtained and the fluorescent spectrums of the atoms are detected. Using the fluorescence,the number of three isotopes 88Sr,87Sr ,86Sr is measured,which is 1.759×106,1.759×105 and 2.638×105 separately.

TiO2 and SiO2 are chosen as the film materials. A Macleod software is used to optimize the film systems. Vacuum depositing method with the aid of ion assistant deposition systems is adopted,through optimizing technical parameters,reducing thickness error,multi-band filter film is successfully deposited on the substrate of quartz crystal. In the condition of vertical incidence,the average transmittance exceeds 95% in 420-640 nm and 920-960 nm,below 3% in 680-880 nm and 990-1100 nm. It conforms to the environmental stability standards,completely meets the demands of infrared night-vision camera.

An optical element cleaning experiment with activated oxygen by synchrotron radiation (SR) is designed to research the cleaning process of carbon contaminated optical element surface. The thickness of sample carbon contamination layer is about 10.3 nm before cleaning process. Synchrotron radiation light is guided into a vacuum chamber which is filled with 1.0 Pa dry oxygen. The research shows that oxygen can be activited by SR and the graphite-like C on Si wafer can be removed effectively. By measuring the reflectivities of sample before and after cleaning process and comparing with IMD simulations,the C removal rate is about 1.75 nm/h.