The bending characteristics of distributed feed back fiber lasers were investigated. Firstly, a theoretical model of fiber lasers output wavelength and bending radius was presented. It shows a linear correlation between the output wavelength variation of fiber lasers and the inverse square of the bending radius, and as the bending radius increases, the Bragg wavelength experiences a blue shift. In corresponding experiments, 3 fiber lasers were used to test output wavelength with bending radii between 10 mm and 90 mm; these experiments demonstrate the accuracy of the theoretical analysis. Secondly, fiber lasers output power and bending radius were studied. One fiber laser was used as reference to eliminate environmental interference. The experiment shows fluctuation ranges of fiber lasers output power are less than 2 dB during the experimental time in 32 days. Finally, the slope efficiency is investigated, showing excellent bending insensitivity. The results provide an important reference for DFB fiber lasers in applications of bending sensing.

In order to shun the wake vortex hazard and assure the flight security, the technique of wake vortex detection by Lidar was studied. The basic principle of wake vortex detection was introduced, and both the detection mode and the system parameters of Lidar were also given. Based on the designed scheme of wake vortex detection by Lidar, the relationships between Doppler spectrum value and the parameters of aircraft type, flight and environment were studied. The radial velocity distribution law of wake vortex was acquired, and its the Doppler spectrum model of laser echo was built. Moreover, the optimal parameters estimation algorithm was selected for wake vortex characterization. Based on the performed wake vortex detection experiment of A340, both the feasibility of wake vortex detection by Lidar and the validity of parameters estimation algorithm of wake vortex were verified.The research results show that the laser echo created of wake vortex is inversely proportional to the cube of radial velocity, but is directly proportional to the square of circulation.

Femtosecond laser inducing refractive index modification has provided a flexible avenue to three-dimensional photonic devices. Having polarization dependent guiding properties, femtosecond photowritten type II waveguide can be used as waveguide polarizer, but it experiences high loss for reserved polarization component. A new type of low loss waveguide polarizer fabricated in fused silica using femtosecond laser was reported. It consists of a type I waveguide in the middle and two type II nanograting traces on both sides. Based on the polarization dependent scattering properties of nanograting indued by femtosecond laser, the evanescent field of type I waveguide was modulated by the type II nanograting traces. Because the mode having a polarization perpendicular to the nanograting experiences a higher scattering loss compared with the mode having a polarization parellel to the nanograting, the latter was transmitted more efficiently. Firstly, polarization extinction ratio as a function of the separation between type I waveguide and type II nanograting trace was investigated. Using the best separation, polarization extinction ratio as a function of the length of type II nanograting trace was further investigated. Extinction ratio up to 15.91 dB between orthogonal polarizations have been realized with a separation of 6 μm and a type II nanograting trace length of 6 mm. Higher extinction ratio could be easily realized by increasing the length of type II nanograting traces or the amount of type II nanograting traces.

The spatial locations of the beam in spatial resonator gyroscope under different maladjustments were mainly studied. According to theories of Collins′s Integral and Collins′s EIKONAL Function and making full use of the MATLAB software, the beam transmission of RLG was simulated and calculated because of the resonator′s maladjustment. From the simulation results of three different structures, it was found that different mirrors with the same maladjustment cause different results on the beat output, and the beat signals detected from mirror M1 and M2 are different; for the small-gain lasers, the structure using the spherical mirror can easily form the stable beam structure compared with the plane mirror; from the calculated spatial coordinates xn it can be got that the centers of the Gaussian spot of clockwise and counterclockwise wave occur shift and effect the beat output of laser gyros in the certain amount of offset. This work has some instructive significance on the engineering testing and endoscopes adjustment of the laser gyro, and contributes to the improvement of measuring accuracy of laser gyro.

It is investigated that the characteristics of the liquid surface wave amplitude change with the exited depth. Diffraction patterns from the liquid surface acoustic waves(SAW)，which is produced by the exiting needle, were observed. Diffraction patterns from SAW corresponding different exiting depths were found. The relation between the diffraction pattern distribution and the surface acoustic wave amplitude was achieved and this relation was programmed. Then, the dependence of the amplitude on the exited depth was obtained further. It was found that the surface acoustic waves amplitude decreases exponentially as the exited depth increase based on the least square method.

An optical system for short wave infrared imaging spectrometer was proposed based on prism-grating-prism(PGP)component. The system is composed by off-axis TMA, collimator, PGP and re-imaging lens, and its response covers the range 950 to 2 500 nm with a 22.5°field of view. The system is able to achieve wide field and broadband. By optimizing the PGP paramters and tilting the reimaging lens along the spectral dimenstion, keystone and smile became slight and were even less than 5 micrometer. Thus the obtained spectral data were more exact.

A method called “wavelet packet approach to sub-band decomposition independent component analysis” was introduced to unmix hyperspectral mixed pixels. Using wavelet packet decomposition technique to improve independent component analysis, a blind unmixing method for hyperspectral data was proposed considering the characteristics of hyperspectral data, and this method could overcome the drawback derived from statistical independence assumption in independent component analysis. Two groups of synthetic data and three groups of indoor data were used to evaluate this method. The experiments show that spectra and fractional abundances of the endmemebers can be retrieved precisely using the proposed method, and its accuracy is significantly higher than that of independent component analysis. This approach is useful for blind unmixing of hyperspectral remotely sensed imagery.

The imaging performance of type I holographic concave gratings would be seriously deteriorated by the recording parameters error during fabrication of the gratings. A numerical simulation was made for analyzing the effect of recording parameters error on imaging performance of the grating. The following conclusions can be obtained from the simulation results. Firstly, the larger the difference between errors of the two recording distances, the worse the imaging performance becomes. Secondly, the recording angle error remains very small because the recording distances for type I gratings are usually very long. The image widths would not change significantly. But the locations of the images would change because the grating constant is different from the desired value. Finally, it is very important to make the curvature radius as close to the namely value as possible, because the radius error would greatly deteriorated the focusing abilities of the gratings. This study can give theoretical guidance to the fabrication for type I holographic concave gratings and reduce the alignment difficulty for the Rowland circle spectrographs.

Dimensionality reduction is a common preprocessing for hyperspectral image, and Kernel Principal Components Analysis(KPCA), as a common feature extraction method, makes use of nonlinear mapping to capture higher-order statistics of data. An optimization sample set algorithm, which is used in KPCA for dimensionality reduction of hyperspectral image was proposed. This algorithm picks sample set used in KPCA taking the statistics of the whole hyperspectral image into account simultaneously, and the minimum sample set with similar energy distribution of the full image is the final selection. The algorithm was implemented in IDL7.0 and tested by using the real hyperspectral image from Cuprite. The experiment results show that the new algorithm is able to save computing time significantly and perform better than conventional KPCA in dimensionality reduction.

The N-doped β-Ga2O3 films were grown on Si and quartz substrates by RF magnetron sputtering in different ammonia partial pressure ratios (from 0% to 30%). The influence of ammonia partial pressure ratio and annealing treatment on the optical and structural properties were studied. The microstructure, optical transmittance, optical absorption and optical energy gap of the N-doped β-Ga2O3 films were significantly changed with the increasing of ammonia partial pressure. The green, blue and ultraviolet emission bands were observed and discussed.

Under room temperature, ZnSe/Ag/ZnSe transparent conducting film was fabricated by electron beam evaporation based on infrared material ZnSe and metal Ag. The ZnSe/Ag/ZnSe film has the electron density of 1.208×1020 cm－3, the electron mobility of 17.22 cm2V－1s－1, the resistivity of 2.867×10－5 Ω·cm, and the work function is 5.13 eV. The ZnSe/Ag/ZnSe film shows an average visible transmittance of more than 80% by theoretical modeling and 63.8% by measurement. The maximum measured transmittance of 83% can be obtained. The results indicates that ZnSe/Ag/ZnSe film has good optical and electrical properties that can be used as transparent electrode in optoelectronic devices.

In order to improve the stability of Traditional Chinese Medicine′s fluorescence fingerprint spectra of constructing images and data processing efficiency, Liquid Crystal Spectrometer was used to detect spectral image of Cortex Phellodendri and Total Saponins of Panax Ginseng. Effective pixels were extracted using the combination of filter and localizing pixels means, besides, their pixels′ spectral images were obtained to draw Traditional Chinese Medicine′s fluorescent fingerprints correspondingly. Considering their Euclidean distance, when compared the three methods, the combination of filter and localizing pixels means has the best fluorescence fingerprint and spectral stability, followed by the background differencing, then is the optimization of pixels. By experimental results, it is revealed that spectral stability by this way is better and can be used to build Traditional Chinese Medicine′s fluorescent fingerprints. Based on these points, a new approach used for collecting effective pixels during Traditional Chinese Medicine′s fingerprints construction is proposed.

In order to explore the property of the conical anterior chamber phakic intraocular lenses (PIOL) in the spherical aberration correction, spherical and conical surface PIOLs were designed, and the characters of spherical aberration correction were researched. Based on the model eye of R. Navarro et al, the spherical and conical surface anterior chamber phakic intraocular lenses for the ametropia correction were designed with ZEMAX software. After the comparison of modulate transform function (MTF) and Zernike spherical aberration, and the analysis of Seidel spherical aberration, it was found that compared with a spherical surface, on the premise of the ocular refractive error being corrected, the conical surface can correct the spherical aberration and make MTF improved observably for hyperopia more than myopia. The correction of spherical aberration for myopia with spherical and conical PIOLs is equivalent. This conclusion would be useful for the design and application of anterior chamber PIOLs.

The reason of the two kinds of optical noise including grid noise and speckle noise is analyzed. A method of reducing the both two kinds of optical noise by a moving random phase plate is introduced. And the theoretic principle is deduced. A micro projector model is designed, in which a random phase plate is driving for vibration by a micro electric controlled motor. The projected imaging was obtained by a CCD camera with different F# and exposure time. The speckle contrast of the projected imaging is calculated. It is shown in the results that when the random phase plate is static, the grid noise can be reduced well. When the random phase plate is vibrated in a frequency higher than the frequency based on the vision hysteresis, the two kinds of optical noise can both be reduced. The final speckle contrast of the projected imaging is less than 5%, which can be satisfied with the projection display application.

High precision automatic tracking system is indispensable component of solar concentrator. Whether signal collector gathers the signal from sunlight direction accurately and reliably or not is the key of automatic tracking accuracy. A design scheme about signal acquisition device of rough and fine adjustment complementary was put forward. One set differential-mode signal could be automatically chosen from two sets sensors by the software during normal work. The scheme effectively resolved the contradiction between a large range looking for the sun and high accuracy tracking. A new structure of collection the signal of concentrating solar was improved, which could solve the problem of photoelectric sensor go into saturated zone in the large light intensity and the output differential-mode signal is too small when the light intensity is very weak. According to the principle, a made signal acquisition device of concentrating solar with rough and fine adjustment complementary was applied to the company′s CPV type 1200W GaAs power generation systems, and achieved very good tracking result with the actual tracking error ≤0.1° (solid angle).

A digital signal proccessing (DSP) algorithm, nonlinear compensation based on Manakov equation, was applied in coherent 40Gbit/s polarization-division multiplexing quadrature phase-shift keying (PDM-QPSK) transmission systems to compensate the nonlinear impairment in optical fiber. The back propagation algorithm based on Manakov equation can reduce the interaction between nonlinear impairment caused by Kerr effect and polarization mode dispersion (PMD) while the traditional back propagation based on scalar nonlinear Schrdinger equation (NLSE) neglects the PMD and cannot compensate the impairment caused by PMD in the polarization-division multiplexing transmission systems. The perfomance of nonlinear compensation based on Manakov equation was verified. Both simulation and experimental results show that the Manakov equation based algorithm exhibits better performance of 400 km-long QPSK transmission comparing with NLSE, with a Q-factor improvement of approximately 3 dB at an OSNR of 18 dB.

The CdSe/ZnS-quantum-dot doped fiber (QDF) in an ultraviolet (UV) curable adhesive background is manufactured in this study. The photoluminescence spectra are measured in different fiber lengths and with different doping concentrations, and absorption coefficient of the QD in such a background is also determined. There is evidence to show that the PL-peak intensity depends on both the doping concentration and the fiber length. The UV curable adhesive can be a desirable choice for preparing the QDF in laboratories due to small absorption, low shrinkage factor, matching fiber-cladding refractive index, and steady optical property.

Based on the photo-elastic effect and index ellipsoid, the relationship between transverse force and dielectric constant variation of polarization maintaining fiber(PMF) was obtained under the consideration of the difference between isotropic and anisotropic optical fiber under transverse force. Polarization coupling characteristic of PMF under transversal force was analyzed based on coupled-mode theory.The relationships between the coupling intensity and the amplitude, direction and the acting length of the transversal force were clarified by numerical simulation. When the direction of force was 45°, the coupling intensity of PMF was the best sensitive to the transversal force.The output extinction ratio changed periodically with acting length of the force, and different amplitude of the force corresponded to different period. The linear relation between the output extinction ratio and the amplitude of transverse force in the part region was found. These characteristics are consistent with previous experimental results.

Equalization technique is an usual way to solve the inter-symbol interference problem in communication system. The dual-mode modified multi-mode algorithm and modified decision directed algorithm were combined in the fractionally-spaced equalizer to improve the performance about convergence speed and steady residual inter-symbol interference which produced by traditional constant modulus algorithm. The dual-mode was used to adjust equalizer, and the equalizer was further adjusted by switching to decision directed algorithm. And fractionally-spaced equalizer solves the spectrum aliasing problem, caused by baund-spaced equalizer because the sampling rate is not high, thus the performance of equalizer was further improved. Monte Carlo simulation shows that the algorithm has fast convergence with lower residual ISI.

Out-of-plane and in-plane reorientations of mesogens were observed upon a linearly polarized light irradiation of azobenzene containing side-chain liquid crystalline polymer, which were characterized by the transmission various and polarized optical microscopy observation of the pumped film. Higher power density polarized light (20 mW/cm2) irradiation on the film induces that a maximal value of the photoinduced transmission is firstly obtained and then a decrease in the transmission value was observered. This suggests an out-of-plain orientation happened. Out-of-plane orientation decreases the stability of the oriented mesogens, which is confirmed by the lost of the anisotropy when the exposure light turn-off. The in-plane and out-of-plane reorientation depend on the laser fluence. The photoinduced anisotropy measurements results reveal that a stable orientation occurred by using an unsaturated irradiation upon a low power density laser beam. The unsaturated irradiation enables to shorten 95% of the incident time and increases the orientation order 1.3 times as compared to that of full orientation. A quick and high stable bit recording is achieved by unsaturated orientation upon 4 ms light irradiation.

In order to improve the shortages of the phosphor for white LED, including low efficiency, poor uniformity, large light decline, short life, and poor physical and chemical characteristics, etc., single crystals phosphor was studied as a substitute. Growth and spectra characteristics of Ce doped and Ce, Pr-codoped YAG single crystals phosphor used for white LED were investigated. Ce∶YAG and Pr,Ce∶YAG single crystals were grown by Czochralski method, and its luminescence properties were studied by means of absorption, emission and excitation spectra. Date analysis reveals that broad emission band ranging from 480~650nm, is produced with blue light excitation. It has been found that red light component of Ce∶YAG phosphor, which is important to improve the color rendering index, can be efficiently compensated by Pr-codoping.

A novel means of lens focal length measurement was proposed based on Hartmann-Shack principle of wavefront detection. Mathematical approaches of focal length measurement were deduced. In the experiments, laser sources with wavelength of 633 nm and 780 nm were separately used and focal length of three pieces of doublets were measured by the two wavelengths.The results show that the measured result can truly reflect the designed focal length by using 633 nm wavelength laser beam, which indicates that this measurement method is feasible and reliable. Meanwhile, the measured result by using 780 nm wavelength laser beam shows larger differences compared with its 633 nm counterpart, which reveals that this method can also be used to evaluate residual spherical aberrations, chromatic aberrations and manufacturing tolerance.

In order to explore the feasibility of vibration sensing behind barriers by terahertz interferometry, a terahertz interferometer was built based on a Michelson interferometer and using 214.58 μm CO2 laser pumping gas THz source. Small vibrations behind a thin cardboard caused by knocking a target mirror was measured by the terahertz interferometer . With some data processing techniques such as phase analysis and spectrum analysis, vibration time-histories and time-frequence distribution were resolved. The maximum of measured peak-peak amplitude is 17.54 μm and the minimum is 7.98 μm. The calculated peak velocity is about 2.7 mm/s. The maximum and minimum of vibration frequence are 58 Hz and 21 Hz, respectively. The results show that terahertz interferometry is a convenient novel technique that senses vibrations behind barriers, and can effectively overcome disadvantages of conventional vibration sensors.

The compositions of each part on the focal plane array (FPA) are not likely the same because of the manufacture defects. The defects will cause the inherent differences between pixels while the focal plane array is conducting the photoelectronic conversion. This paper has derived the theoretical model of the nonlinearity of the cooled detector corresponding to the composition x, which is based on the research project of the domestic 640×512 MWIR cooled thermal imager. The infrared radiation received by the FPA and converted into photocurrent, this type of current has significant relationship with the nonlinearity of the detector according to the composition x in the Hg1-xCdxTe material. A black body was used to radiate the detector under the wide working temperature of the detector, and amount of experimental data were collected under every pre-set temperature point. According to the parameter change that influence the photocurrent most, a double exponential fitting model was proposed to describe the nonlinearity characteristics of both the total response and the separate pixel response of the detector. Multiple works were carried out by analyzing the response data in the form of diagram and table to prove the accuracy of the real response fitting by this model.

The nonuniformity in the infrared focal plane array limits the quality of infrared imaging system. A new nonuniformity correction procedure based on the unified photoresponse characteristics of infrared focal plane arrays and the correction ratio based on the chi-square histogram were presented. The correction output of each detector took both its observed value and the average response of the focal plane array into account. The correction parameters were obtained by establishing the relationship between the difference of the observed value and its ideal response and the average response of the focal plane array. The proposed correction ratio took into account of both spatial and temporal response characteristics of focal plane arrays, thus it gave more reasonable results on the measurement of the degree of nonuniformity. Experimental results show that its performance is better than that of the two-point correction and the quadratic curve fitting correction using the input values, and has excellent correction capability to the pixels with abnormal responses. In addition, the algorithm has the advantages of high correction precision, less correction factors and easy to real-time processing, which enhances its utility value.

A 1.2 m SiC primary mirror FEA model was built to analyze temperature and support style effects on the large aperture SiC primary mirror, which was applied to the ground based on telescope. With the primary mirror in passive support and free expansion, influences of steady state temperature field, axial direction temperature gradient, radial direction temperature gradient, and internal-external temperature gradient to primary mirror surface figure were analyzed. The result indicates that the influences of the support style are not obvious, whether passive support or free expansion, and the primary mirror surface figure is big with temperature gradient. When achieving heat balance, the influence of the support style is obvious only when the primary mirror free expand, and the temperature influence is small, surface figure RMS<0.02nm/℃. If the primary mirror adopts flexibility or floating support style, the large aperture SiC primary mirror can be applied to the ground based telescope.

By the method of coherent-state orthogonalization expansion, the energy spectrum of the V type three-level atom was calculated exactly in the non-rotating wave approximation, and a level-crossing problem was also considered by means of fidelity. The influences of the initial states of the V type three-level atom and the parameter of the binomial optical fields on the second-order coherence degree were studied. The numerical results indicate that: when the atom is initially in the ground state, the duration of the bunching effect increases at the beginning and then decreases with the increasing of η; when the atom is initially in the coherent state, the duration of the bunching effect decreases with the increasing of η. Finally, both cases of the light fields displayed anti-bunching effect completely when the value of η was large enough. When other parameters didnot change,the average of G2(t) increases with the enlargement of coupling strengh.

In order to find out the effect of atomic motion on the population inversion of two atoms, the atomic states were analyzed by the method of quantum mechanics. It was found that the population inversion of two atoms was related to the field mode structure in an optical resonant cavity when the atoms were moving and the optical field was in coherent state. When two atoms in the cavity were fixed at initial time, the evolvement of population inversion of two atoms was periodic in the case of a small average photo number, and there were collapses and revivals of atomic inversion in the case of a large average photo number. The evolvement of population inversion of two atoms became well-regulated orderly under the coherent cavity field when atoms were in motion at initial time. The population inversion of two atoms will evolve in different periods when the two atoms move in axial direction at different velocity. The period of population inversion is the lease common multiple of periods of coupling coefficients between two atoms and field. When there are more average photon number in the cavity, the oscillation of population inversion will be faster. So it is possible to control the population inversion by properly choosing the velocity of atoms and the initial field.

Compressive imaging is an important application of the theory of compressive sensing. The deterministic measurements were introduced into compressive imaging and a novel method-compressive double lens imaging was proposed using deterministic phase mask. Simulation results show that novel imaging method can effectively capture the information of image, and reduce the difficulty and costs of the hardware implementation significantly. The classical analog-to-digital conversion of optical imaging is changed, the digital conversion costs are reduced, and the image transmission and storage are able to be facilitated by the proposed method, which provides some theoretical, computing and technical support for new design of camera.

A fusion method for meteorological cloud images based on compressed sensing (CS) was presented. Aiming at the frequency aliasing of the original contourlet transform, the aliasing-free pyramidal filter banks (AFPFB) was combined with directional filer banks (DFB) to construct a new transform, called aliasing-free contourlet transform (AFCT). Then, AFCT was applied to the sparse representation stage of CS to decompose the cloud image into dense and sparse components. The dense components were fused using conventional approach while the sparse components were fused under the framework of CS via fusing a few linear measurements by solving the two-step iterative shrinkage/threshold reconstruction algorithm which uses two previous estimates to obtain a new one. The experiment results demonstrate that the proposed method outperforms the traditional methods in terms of visual quality and quantitative criterion, and the fusion results is propitious to reveal the comprehensive weather information.

Those existing robust watermarking algorithm in singular value decomposition domain always inserts an watermark into singular values from singular value matrix.A robust zero-watermarking algorithm based on variance was proposed, using two orthogonal matrices deriving from singular value decomposition. The image was split into non-overlapping blocks, and each block was transformed with singular value decomposition. The zero-watermark sequence was produced by judging the numerical relationship between variance of each element′s square from the first column of U matrix and V matrix. It has perfect invisibility, since no modification has been made to the original image. Its robustness towards resampling, smoothing, noise adding and JPEG compression is tested. The experimental results show that it has strong robustness towards those above attacks.