The influence of the applied electric field and temperature on the dark current of quantum dot infrared photodetectors (QDIPs) was simulated and analyzed, which is based on the dark current model including the common influence of the microscale and the nanoscale electron transport as well as the dependence of the drift velocity of electrons on the applied electric field. The results show that the dark current model has an excellent agreement with the experimental data at 0~25 kV/cm applied electric field. The increasing of the dark current goes with the rise of the applied electric field, and the dark current increases rapidly below about 6 kV/cm, but it increases slowly above about 6 kV/cm. The rapid increase of the dark current goes with the increase of the temperature. The research can provide the theoretical reference in the optimization of the device design and the improvement of the performance of the quantum dot infrared photodetectors.

Radiance model of detection system was built based on background radiation and radiation of high altitude balloon. The radiometric signal electrons in focal plane array produced by high attitude balloon in near space and background radiation were calculated precisely by considering the effects of atmosphere transmission, optical system imaging, detector and detector sampling. Then signal-to-noise ratio was deduced for high attitude balloon in near space. An atmospheric modeling tool, Modtran, was used to model radiance of self-emission, specular background reflection and diffuse background reflection. Radiation characteristic of balloon in complex atmospheric and the influence on optic-electronic equipment′s SNR of specular reflectivity, diffuse reflectivity and integration time were analyzed. The research results indicate that the Visible-Near Infrared Ray(VIS-NIR) (0.6~2.4) detector can be used to detect balloon in sunshine and the Long Wave Infrared Ray(LWIR) (8~12) detector can be used to detect balloon in complex atmospheric. With the integral time of 0.25s, the specular reflectivity of 0.32 and the diffuse reflectivtiy of 0.68, or the integral time of 1s, the specular reflectivity of 0.43 and the diffuse reflectivtiy of 0.57, detection of high altitude balloon can easily been achieved.

Traveling-wave photodiode arrays can combine the output power of the diodes without increasing the bandwidth. To deal with such problem, a kind of high-performance diode groups traveling-wave photodiode arrays structure was proposed. Firstly, two-element near-ballistic uni-traveling-carrier photodiodes were cascaded, and then parallel these two cascaded branches. After that, we have a capacitor in series on these diode groups to form array units. Then these array units were cascaded and connected with inductors based on traveling-wave detector arrays to constitute new traveling-wave photodiode arrays. The power synthesis, frequency response and return loss of traveling-wave photodiode arrays were analyzed and compared. Under the condition of applying the same amount of diode, the output power of the new traveling-wave photodiode arrays is halved and its cut-off frequency is doubled. In addition, compared to traditional structure, the return loss improves more obviously with the number of diodes in arrays increasing. The results show that this new traveling-wave photodiode arrays structure can increase the output power while improve the working bandwidth, better meet the requirements of high-power and high-bandwidth photodetector in future radio-over-fiber wireless communication.

The two-dimensional (2-D) simulations of p-i-n type InP/In0.53Ga0.47As/InP photodetector at low bias were presented. The modeling results fit the experimental results well, verifying the validity of our model and the desirability of the simulated results. In order to further optimize the detector structure, the effects of thickness and doping concentration of the absorption layer on the dark current and photoresponse were both simulated and discussed. One can find that the dark current doesn′t increase when the thickness of the absorption layer is over 0.3 μm. However, the photo-response increases as the thickness of the absorption layer increases. The dark current decreases monotonously as the doping concentration of the absorption layer increases, and when the doping concentration increases to 2×1017/cm3, the dark current reaches the lowest value. Finally, the transient time of photodetector is also simulated under different reverse bias, one can find that the response time can be decreased with the increase of the reverse voltage.

Using the full-vector coupled mode theory, a method for Surrounding Refractive Index (SRI) sensing with a single wavelength was proposed which is based on the core-only photoinduced birefringence of Long-Period Fiber Grating (LPFG). With a completely-polarized light near the resonant wavelength launched into the LPFG, the variation of the spherical distances between the output light polarization states for various SRIs and that for the reference SRI=1 on the Poincare sphere is investigated to identify the SRIs. The analysis indicates that the SRI sensor with a cladding radius of 20.75 μm shows a good linearity performance and high sensitivity of 0.356/RIU over the SRI measurement ranging from 1 to 1.30, which, unlike the available LPFG sensors, may be applied to the humidity and vapor sensing. Meanwhile, the analysis method is applicable to the design of other types of birefringent-LPFG sensors.

By introducing the elliptical hole doped with PG glass into the core of photonic crystal fiber, a graphene structure photonic crystal fiber with high refractive index was proposed. Numerical simulation based on finite element analysis was performed to calculate birefringence in the proposed structure with implementation of different parameters. The effects of air aperture ratio, hole pitch and fiber core ellipse on the fiber's birefringent characteristics were studied. Meanwhile, the optimization was performed by the mode areas and confinement loss of photonic crystal fiber. The results show that, at 1 550 nm wavelength, the high birefringence is 0.13, while mode areas are less than 0.7 μm2 and the confinement loss are less than 10－6 dB/km in two modes. The fiber efficiently can protect the polarization in light transmission, providing basis for the realization of super-continuum spectrum of high-stability.

Based on the mode-reorganization mechanism of long-period fiber grating induced by the increase of film thickness, the influence of cladding radius on the characteristics of long-period fiber grating -based film sensor was investigated. The results show that the reduction of fiber cladding can improve the sensitivity of film sensor in a great manner for given film parameters and enlarge the dynamic range of the response of film sensor to the variation of film thickness. Moreover, the sensitivity-increasing effect caused by cladding reduction is degraded by the increase of film thickness. In experiment, the cladding was reduced with hydrofluoric acid and the organic film of PAH/PAA was deposited by electrostatic self-assembly method. The theoretical results are confirmed by analyzing the spectral data during film deposition. The application of this film sensor in pH sensing shows the sensitivity reaches 3.93 nm/pHU when the cladding was 39(m and film thickness was 424 nm, which was two times as high as that of common fiber cladding.

The effects of R0,m and TR2,m acoustic modes of guided acoustic wave Brillouin scattering on gain, phase modulation and additional birefringence in single mode fiber were investigated by the all-vector finite element method. The results show that the gain of guided acoustic wave Brillouin scattering reaches maximum at their frequencies matching those of R0, 8 and TR2, 10 modes in R0, m and TR2,m (0°/90°) mode, and the gain increases with the increasing of pump power. The Stokes wave phases modulated obviously by R0,1, TR2,5, TR2,7 and TR2,10 modes, where TR2, m mode plays a vital role in the phase modulation which linearly increases with the increasing of pump power. TR2,1,TR2,5,TR2,7,TR2,10 modes obviously induce additional birefringence which linearly increase with pump power increasing.

Based on the high temperature and refractive index sensitivity of long period fiber gratings (LPFGs) and the high reflection efficiency of the fiber Bragg grating (FBG) filters, a temperature and refractive index sensor was designed, which is a cascaded LPFG based on the FBG filter. The temperature and refractive index were measured by using the FBG filter to reflect partial power of interference wave of the cascaded LPFG into the power meter. In this paper, the feasibility of the cascaded LPFG based on FBG filter temperature and refractive index sensor was analyzed by the signal superposition principle. Then, the binomial fitting was done between the power meter readings and changes of the temperature, and the power meter readings and refractive index. The determination coefficients are 0.9990 and 0.9959 respectively. The high stability of the proposed sensor was also tested. These results show that the cascaded LPFG based on FBG filter temperature and refractive index sensor could be used for the precise measurement of the temperature and refractive index and has a high stability.

An endmember extraction method was proposed based on the maximum N dimensional solid spectral angle theory, which was termed as MNSSA (Maximum N-dimensional Solid Spectral Angle) in this paper. By using the ability of calculating the solid spectral angle which constructed by N spectral vectors in the high-dimensional Euclid space for the method, the independences of the N spectral vectors were measured. In the assumption of linear unmixing model, the solid spectral angle constitutes the maximum value for N endmember spectral vectors. The MNSSA method is not restricted by the numbers of endmembers or the numbers of bands. More importantly, the MNSSA method is not sensitive with the amplitude variations as well as robustness with effects from shadow strength and illumination intensity. Experiment results on synthetic and real hyperspectral data collected by AVIRIS (Airborne Visible/Infrared Imaging Spectrometer) indicate that the method of MNSSA is better than the current mainstream used endmember extraction methods. The influences on the amplitude of the endmembers caused by the shadow factor are overcomed by the method of MNSSA. The method is with good anti-noise performance. Furthermore, the reconstruction errors for real hyperspectral data were reduced remarkably.

In order to improve the fusion quality of multispectral image and panchromatic image, a remote sensing image fusion algorithm was proposed based on Non-subsampled Dual-tree Complex Contourlet Transform(NSDTCT) and sparse representation. Firstly, the Intensity-Hue-Saturation(IHS) transform was applied to the multispectral image. Then, the histogram matching and smoothing filter-based intensity modulation were used to handle intensity component and panchromatic image. Secondly, the NSDTCT was employed to decompose the new intensity component and panchromatic image, and the low frequency coefficients and high frequency coefficients were obtained. For the low frequency coefficients, a fusion method based on sparse representation was presented, and the fused coefficients were obtained by combining spatial frequency with l1-norm maximum. For the high frequency coefficients, the sum-modified Laplacian was used for the external input of Pulse Coupled Neural Network(PCNN), and a fusion method based on the theory of improved PCNN was presented. Finally, the fused image was obtained by inverse NSDTCT and inverse IHS transform. The experimental results show that the proposed algorithm can improve the spatial resolution and maintain the spectral characteristics simultaneously, and outperforms other classical fusion algorithms in terms of both the visual quality and objective evaluation.

The relationship of the gain logarithm and voltage of microchannel plate is linear in theory. In order to be closer to the actual situation, according to the known function between the voltage and logarithmic gain of microchannel plate, a set of linear data points added random numbers were selected, and the new relationship of the voltage and logarithmic gain was obtained which can be used to restore the target distance information. The analysis results of imaging accuracy show that the imaging accuracy is related to the system’s signal noise ratio and gain modulation function, the higher signal noise ratio is, the higher the distance accuracy is. The relationship between the gain and the voltage of microchannel plate was measured. The echo images in different voltages conditions were obtained by illuminating the same target at the same distance, the gray value ratio of the echo images under different voltages was used to get the ratio of relative gain. Respectively under the condition of constant gain and modulation gain, the target which was 60 m far from the imaging system was imaged. By using the gain curve, the obtained images were processed and the distance information of target accurately was restored, the distance accuracy could reach decimeter magnitude.

A set of moments was proposed based on Bessel function under three kinds of boundary conditions, named Bessel-Fourier moments, which are defined in polar coordinate and regarded as a generalized orthogonality complex moment. The radical polynomials of the Bessel-Fourier moments have many zero points and most of them are distributed uniformly. The reconstruction experiments of 26 uppercase binary images and the classification experiments of 1260 gray butterfly images were used to validate the proposed method, and different Bessel-Fourier moments under three kinds of boundary conditions wre extracted as the feature values of image analysis (image descriptor). Theoretical and experimental results show that, compared with the orthogonal Fourier-Mellin and Zernike moments, the Bessel-Fourier moments are more suitable in image analysis and rotation-invariant object recognition, and performed better than the orthogonal Fourier-Mellin and Zernike moments in terms of image reconstruction capability and invariant recognition accuracy.

To investigate the flywheel micro vibration effect on the camera imaging quality, the method of integrated modeling and ray tracing was used. The integrated modeling is to set up disturbance model of the micro vibration of the flywheel, the finite element model of the satellite and the camera. By the transient response analysis, the displacement of all the mirror with the time under the action of force or moment in 6 directions respectively is obtained. The ray tracing is based on reflection mirror displacement and the incident light, according to the refraction law to calculate the location and direction of the ray, and the angle between the ray and the optical axis. Then, the spot coordinates and displacements of the image plane are obtained, and the Modulation Transfer Function (MTF) of the system is calculated by using the statistical moment of motion. The results show that the response period has nothing to do with the excitation period; the length of excitation time and sampling time affect the MTF; different direction vibration causes the change of MTF of different sizes, indicating the size of angular and linear vibrations on MTF; and different direction effect on MTF is similar between with the original optical system and with only vibration, where MTF attenuation reaches maximum when My, Mz is loaded respectively, up to about 0.1. The research method is simple and fast, and the relationship between the micro vibration and the MTF is obtained, which provides reference for the system design and vibration isolation.

The reasons of the generation of defocus were discussed and the defocus change was analysed from the relative distance, atmospheric pressure and temperature change. The modulation transfer function model was proposed to study the image quality influenced by defocus. Then different defocus value leading image blurry was simulated. The simulation results indicate that the positive and negative defocus value induced by the relative distance, atmospheric pressure and temperature change can be counteracted. This paper provides an effective data to spatial camera design, compensating measure establishment and performance evaluation.

By using Principal Component Analysis, the phase and the phase shifts were extracted simultaneously from one set of interferograms, the relationship between the phase shifts and the driving voltages was obtained and then the calibration of nonlinear phase shifts was achieved. Numerical simulations and experiments were implemented to verify the effectiveness of this method. The simulation results show that the calculation error of phase shifts for the method decreases with the increasing of the number of fringes in interferograms. The error is less than 0.1664rad when the number of fringes is larger than 0.25. The experimental results show that the calculation error of phase shifts is a periodic distribution and has few effect on the accuracy of phase shifter calibration. The proposed method without non-iterative has no strict requirement for the number of fringes in interferograms, thus it is an effective and efficient nonlinear phase-shifting calibrating method for piezoelectric ceramic transducer in interferometer.

In order to further improve the precision and quantify the environmental requirement for Point Source Transmittance(PST) test, a method was proposed to quantitatively analyze the impact of air cleanliness on the precision of PST test. This method is based on Mie scatter theory, and uses Monte Carlo simulation to perform a random and large simulation on dust quantity and size for different air cleanness. A case study was performed to find out the actual environmental requirement for PST test, which used a space telescope of 800mm diameter with the designed PST of 10－9. The analysis indicates a minimum air cleanness of ISO class 6 and the PST test error of 10－10 caused by dust, with each additional level of air cleanness, the PST test error will increase ten times.

A method for fast capturing three-dimensional shape and color texture with the black and white camera was proposed based on the absolute phase measuring and active color lighting. First, two stripes with 1/3 period phase shift and one stripe whose period is slightly different with the two stripes are projected. The deformed stripes are captured simultaneously. Then, patterns with the specific color of white, red and green are projected on the objects respectively and the images are captured. Second, by using the fourth image, the first and the second deformed stripes, phase distribution of the stripe is obtained with improved phase shifting method. The phase distribution of the other stripe is obtained with improved Fourier transform method by using the fourth image and the third deformed stripe. Then, the absolute phase distribution is obtained. Finally, by using the fourth image, the fifth and sixth image, the reflected green component of scene is obtained. According to the principle of the colorimetry, the color texture of scene is retrieved. The experimental results show that the high quality color texture and the high measurement accuracy for three-dimensional shape can be achieved simultaneously with the proposed method. The recording speed of the three-dimensional data and the color texture can reach to 30 fps.

In order to improve measurement accuracy of solar radiation observation instrument, aiming at cosine error caused by characteristics of diffusion and Fresnel diffraction,a method of correcting cosine in case of different installation forms and different structures was researched. Considering the solar radiation characteristics and cosine corrector production factor, cosine error correction method was proposed in installation forms of cosine error exposed and cosine error exposed cooperating stop ring, while the method in two structures of cosine corrector and integral cavity was proposed. According to the requirements, cosine error was modulated and simulated by different installation methods by TracePro software. Using high collimation solar simulator, turntable and rotating arm, different directions sunlight were simulated, and the cosine error was measured. The results show that in the installation forms of cosine error exposed cooperating stop ring, the incident angle is less than ±80, the cosine error is better than 6%. The correction method can reduce cosine error effectively with the condition of large incident angle, and improve the accuracy of of solar radiation observation.

The laser characteristics of the Nd-La∶CaF2 and Nd-Sc∶CaF2 co-doping disordered crystals pumped by a 790 nm laser diode were studied. Absorption spectrum and lasing performances of Nd: CaF2 crystal with different La3+-Sc3+ doping concentration were studied respectively. Under the pump power of 5 W, the laser power of 1.10 W and 0.64 W are obtained with the co-doping of 0.5 at.% Nd3+, 5 at.% La3+∶CaF2, 0.5 at.% Nd3+and 3 at.% Sc3+∶CaF2 respectively, corresponding to the slope efficiencies of 23.0% and 12.8% respectively. The laser threshold for both crystals is as low as 10 mW. The results show that the new co-doped crystals are promising laser mediums for high power and high efficiency diode pumped solid-state lasers.

Based on the Spin-flip Model, the nonlinear dynamical characteristics of a 1 550 nm vertical-cavity surface-emitting laser subject to orthogonally polarized beams injection and negative optoelectronic feedback was investigated. The results show that, for a free-running 1 550 nm vertical-cavity surface-emitting laser lasing at the Y linear polarization mode, under suitable injection strength and frequency detuning, 1 550 nm orthogonally polarized optical injected vertical-cavity surface-emitting laser can exhibit many nonlinear dynamic behaviors such as Stable State, Period-one, Period-two, Multi-period, Chaos, Stable Injection Locking and Polarization Switching phenomena. Then, after introducing the negative optoelectronic feedback, some new nonlinear dynamic behaviors, such as Double Frequency Quasi-periodic Oscillation, Triple Frequency Quasi-periodic Oscillation, can be observed. For a certain feedback delay, the dynamic distribution regions of the orthogonally polarized optical injected vertical-cavity surface-emitting laser outputs in the parameter space of injection strength and frequency detuning will be influenced by the optoelectronic feedback strength. Under certain optoelectronic feedback strength, for relatively small injection strength, the feedback delay has an obvious effect on the dynamic distribution regions in the parameter space of injection strength and frequency detuning. For relatively larger injection strength, the delay time has little effect on the dynamic distribution regions and the laser almost operates at Period-one or Stable Injection Locking state.

Cu-Zn-In-S/ZnS core/shell quantum dots (QDs) with various Cu/Zn molar ratios were synthesized by a hot-injection method. The effects of Cu/Zn ratios on the photoluminescence (PL) properties of Cu-Zn-In-S/ZnS core/shell QDs were investigated by UV-vis absorption, steady-state, and time-resolved PL spectroscopy. It could be observed that the Cu-Zn-In-S/ZnS QDs with various Cu/Zn ratios exhibited zinc blende structure and similar grain sizes. The blue shift in absorption onset of Cu-Zn-In-S/ZnS core/shell QDs increased with reducing Cu/Zn ratios, resulting from widened bandgap of the QDs due to the difference in QD composition. The corresponding emission wavelength of QDs was also blue-shifted from 640 nm to 529 nm when Cu/Zn ratios decreased from 6/1 to 1/6. The Cu-Zn-In-S/ZnS core/shell QDs exhibited an enhanced PL quantum yield with decreasing Cu/Zn ratios because Zn2+ substituting Cu+ could inhibit the defect formation of Cu interstitial atoms. In addition, Cu+ ions emission is observed in the sample with Cu/Zn=1/6, companying with longer PL lifetime.

In order to get the relationship between rare earth luminescence fluorescence characteristic parameters (including fluorescence lifetime, intensity and branching ratio) and temperature. The relationship between the particle number distribution of the excited levels and temperature was studied using the typical level structure of rare earth materials and the Boltzmann distribution of thermal equilibrium between the multiple level of excited state. It was found that with the increase of temperature, fluorescence life and branching ratio of high level in excited state are increase too. And the intensity of fluorescence will decrease after increase first due to the influence of non-radiation transition coefficient and energy transfer efficiency. Forwardly, a experiment was designed to measure the fluorescence characteristic parameter of Y(P,V)O4∶Eu3+, pumped at the wavelength of 395 nm, at different temperatures from 95 K to 510 K. The experimental results are in good agreement with the theory conclusion..

In order to calibrate the wave aberration caused by large aperture mirror in high resolution space camera, a deformable mirror suitable for space environment was designed. The design criterion of deformable mirror used on space camera was discussed, and the structure form of the deformable mirror was determined; the concrete structure and combination of materials were given, and the flexible structure was added. Simulation results show that, its RMS value is 17.2 nm under z axis gravity and only 3.7 nm when temperature is increased by 4℃, its 1st natural frequency is 1 015 Hz, and after active flattening, the reflecting surface under these simulated space conditions can be corrected to approximate standard plane; it can accurately fit the wave elements corresponding to the first 36 Zernike polynomials, and the residual errors are small. This deformable mirror not only has good mechanical properties and thermal stability, but also can guarantee the aberration correction ability, which meets the application requirement of space camera.

Detecting a 4.5 magnitude star in the observation height of 10 km, the radiance of stars between 600~1 100 nm was analyzed, the radiance of sky background and the optical transmission of atmosphere were calculated by using Modtran. When the threshold of SNR is 5, typical parameters are selected. With a plane mirror and a silicon material sphere lens, a lighter miniature optical system was designed. The result shows that the optical system spot shape approaches a circle between 600~1 100 nm of full field of view, modulation transfer function approaches perfection and have outstanding image of quality. The Ground-based daytime and nighttime detection SNR of the star tracter is calculated and the detection ability limit is estimated in the threshold 5 of SNR, which is 2.5 stellar magnitude G star in daytime on the ground and 6 at night.

The ultra-broad band anti-reflection film of 1300~3400nm waveband was designed and fabricated on TeO2 acousto-optic crystal. Starting the theory of thermal stress of thin film with the properties of TeO2,the stress diagrammatic sketch of thin film was established.Combing the properties of TeO2 crystal with torque determination method, the thermal expansion coefficient and Young’s modulus of the thin film materials were analyzed by analytical method of reverse calculation.The experiments show that the adhesion is better prepared under the same process conditions by using connecting layer. The film is protected from the problem of stripping and meets the corresponding requirements of adhesion test.

For the problem that the total power of photovoltaic power system declines sharply, when the photovoltatic array is affected by the partial shading, the group control method was adopted to connect PV array and inverters by the switch matrix. The flexible topology structure of photovoltaic power generation network was formed. Then, the working principle of topology structure was introduced and the corresponding adaptive genetic algorithm to realize the group management between distributed photovoltatic array and inverters was proposed. The simulation and experiment results show that the convertion efficiency of optical energy used by the algorithm is much better than that of conventional distributed photovoltaic power for the shade of photovoltatic array, and providing a way for the effective use of optical energy.

In order to study the influence of the initial voltage, arc length, fill pressure and bore diameter of charging capacitor on current pulses and light pulses of the xenon flash lamps, at a pressure of 13.33~53.32kPa, the change of current pulses and light pulses were measured with the arc length of 100~300mm, the bore diameters of 6~12mm and the initial voltages in charging capacitor ranging from 1.75kV to 4.25kV. It was found that the pulse widths of light pulse and current pulse change from 15μs to 45μs. The result showed that with the higher voltage in charging capacitor, stronger peak current could be obtained, the width and delay of light pulses reduced. High fill pressure or long arc length can diminish the strength of peak light, expand the width of light pulses and extend the delay time. Although big bore diameter raises the peak current, it also expands the width of light pulses and diminishes the strength of peak light.