A switchable operation of rectangular dissipative soliton and Gaussian-spectrum pulse has been investigated experimentally in the mode-locked fiber laser using single-walled carbon nanotube and nonlinear polarization rotation technique. The rectangular dissipative soliton is strong chirped with the temporal and spectral width of ~6.33 ps and ~12.54 nm, respectively. By appropriately adjusting the polarization states, the Gaussian-spectrum state with ~1.87 ps duration and ~2.2 nm bandwidth is achieved. The time-bandwidth product of the Gaussian-spectrum pulse is 0.51, suggesting that the pulse is nearly chirp-free. The switching of different operations could be ascribed to the change of cavity polarizations relying on polarization controllers, which is also demonstrated by the simulation results.

In order to realize the π phase-shift fiber grating fabrication with different coupling coefficients by shielded method, the phase-shift principle is analyzed, and the method of controlling the coupling coefficient of π phase-shifted fiber grating by regulating the length of shielded length and the number of occurrences of π phase shift is proposed. The transmission matrix method is used to simulate the transmission spectrum change during the phase-shifted grating fabrication process. The influence of shielded length on the transmission spectrum of the phase-shifted fiber grating is analyzed under different grating fringe visibility. The phase-shifted fiber grating fabrication experiments are carried out based on different shielded length. The results show that the effective control of the phase-shift fiber grating coupling coefficient can be achieved by adjusting the shielded length and the number of phase shift cycles.

In order to monitor and accurately locate the leakage of the reactor cooling system in the nuclear power station, the distributed temperature sensor is constructed by using Raman scattering effect and optical time domain reflection technology. Combined with the specific rules of the sensing fiber layout, to achieve full coverage online monitoring of the temperature field outside the pipeline in real-time. It is verified by experiments that when the leakage causes the temperature anomaly in a certain area of the two-dimensional plane to reach a preset threshold, the monitoring system will position and mark the point according to the wiring rules, thereby achieving accurate positioning of the two-dimensional plane. The positional accuracy obtained by the experiment is 0.5 meters, and the probability of false alarms is significantly reduced, which can greatly improve the positioning accuracy of the abnormal point of the temperature on the outer surface of the pipeline.

To better the contrast of the images under the mine and suppress the influence of dust and noise, a mine image enhancement algorithm based on dual domain decomposition is proposed. Firstly, input images are decomposed into low frequency images and high frequency images respectively using bilateral filter. Secondly, haze removal and contrast enhancement of the low frequency images are realized by using the fast-dark channel prior dehazing algorithm and gamma transform. After that, non-subsampled Shearlet transform and second order differential operator are adopted to realize the high-frequency image denoising and enhancement. At last, the enhanced high-frequency and low-frequency images are composited into basic enhanced images followed by suppression of dust blur and over-exposure white artifact to obtain the desirable enhanced images. Result of the experiment shows that our algorithm is widely applicable for it not only can enhance the contrast of the images under the mine but also suppress the haze and noise effectively.

In order to improve the dehazing effect of foggy images, an image defogging algorithm based on conditional generation against network was proposed. Through end-to-end trainable nerves, the network trained the synthesized indoor and outdoor data sets. In order to capture more useful information in the image, the generator and discriminator architecture was designed in the generation network, the loss function was modified using the pre-trained visual geometry group feature model and the L1-regular gradient pair loss. At the last level of the discriminator, the Sigmoid function was applied to the feature map for probabilistic analysis to be normalized. By using the synthetic data set to train the loss function, the parameters of the new loss function were obtained, and then the new trained loss function was tested by the outdoor natural fog image data set. The experimental results show that the algorithm effectively solves the problem of color distortion, oversaturated, and visual artifacts, resulting in a better defogging image.

In order to improve the spatial resolution of multispectral images while maintaining spectral information to a greater extent, this paper proposes a remote sensing image fusion based on multivariate empirical mode decomposition and weighted least squares filter. On one hand, multivariate empirical mode decomposition solves the problem of spatial information distortion caused by the subimage frequency mismatch between the intensity component of the multispectral image and the panchromatic image in traditional remote sensing image fusion methods based on univariate empirical mode decomposition. On the other hand, remote sensing image fusion based on multivariate empirical mode decomposition usually suffer from serious spectral distortions due to the detail information contains low frequency components. To overcome these defects, the weighted least squares filter can estimate low frequency information of source image accurately and obtain the high-frequency information subsequently. Combine the advantages of both, the fused image obtained by different fusion rules has better spatial detail and spectral information retention. In this paper, different satellite data are selected for simulation experiments, and compared with other methods such as based multivariate empirical mode decomposition and àtrous wavelet transform and based on weighted least squares filter, the results of experiment achieve good performance in both spectral and spatial qualities.

For wind shear detection and early warning in civil aviation airport, a three-dimensional lidar was proposed. The lidar adopts pulse coherent detective way of all-fiber, a unique spherical 2D photoelectric scanner and an innovative glide scanning strategy, which realizes the simultaneous measurement of head wind and crosswind shear of glide path. The lidar was tested at Panzhihua Airport from March to November in 2018, which observed the detailed distribution of atmospheric flow and wind shear over and around the airport using a variety of working modes. During the wind season from March to May, the wind shear reported by the crew was detected by the lidar. The most serious case was analyzed, which proved the effectiveness of the 3D lidar in detecting wind shear in the altitude airport with complex geography and climate.

To solve the problem that the traditional measurement method of axial length is segmented detection and the measurement error is large, a swept-source optical coherence tomography system with large detection range and realized one-time measurement of axial length was designed. In order to reconstruct the large depth interference signal, an algorithm combining adaptive peak point extraction and adaptive error correction was proposed. The CPU-GPU acceleration technology was used to realize the real-time measurement and solve the problem of great data and slow speed of wide imaging range. Optical eye model experiments shows that the measurement error of axial length is 0.01 mm, which is superior to the traditional segment measurement system. The single measurement time is 0.10 seconds, which meets the real-time measurement requirements.

Light reduction experiments were carried out with a 488 nm continuous laser under the same exposure. Simultaneously the properties of reduced graphene oxide (rGO) were characterized by transmittance and resistivity. The results show that during the reduction process, the degree of reduction characterized by resistivity and transmittance presents the same trend. Moreover, the reduction process is divided into two steps: before reaching the relatively stable state and reaching the relatively stable state. Before reaching the relatively stable state, the lower the laser power density, the higher the reduction degree of the samples; but when reaching the relatively stable state, the higher laser power density, the higher the reduction degree of the samples. This phenomenon is further analyzed by means of photon penetration and bandgap modulation, based on the change of oxygenated functional groups in rGO.

CaGd1-xAlO4: xEu3+(CGA∶xEu3+) X-ray storage phosphors with different doping concentrations of Eu3+ were synthesized by a combustion method．In the doping concentrations range of 0~0.150, single phased CGA∶xEu3+ powders are acquired and Eu3+ occupying the sites without symmetric inversion center leads to strong red emissions. For the CGA∶0.100Eu3+ phosphor, the strongest red emission intensity can be observed. As the concentration of Eu3+ ions increases, the distance between Eu3+ ions decreases, increasing the energy transfer probability of Eu3+→Eu3+→annihilation center, and luminescence quenching occurs. When the Eu3+ doping concentration is 0.003, the strongest intensity of the photo-stimulable luminescence can be obtained. For the annealed CGA∶0.003Eu3+ phosphor in nitrogen ambient, the number of OH- groups in CGA is decreased and the red emission intensity is enhanced compared to the unannealed sample. The thermoluminescence analysis shows that there exist two kinds of traps in the CGA∶0.003Eu3+phosphors and the trap depths are 0.79 and 0.93 eV, respectively. In particular, the annealing in nitrogen leads to the increased number of traps, the enhanced photo-stimulable luminescence intensity and the improved storage properties. The nearly linear relationship between the X-ray absorbed dose and the X-ray irradiation time can be found in the range of 0~11.8 Gy. When the X-ray absorbed dose is 1.2 Gy, an imaging plate made of CGA∶0.003Eu3+ heat-treated under a nitrogen atmosphere obtains high-quality X-ray red imaging. The experimental results show that Eu3+ doped CGA X-ray phosphor materials have potential applications in computer X-ray medical imaging with CCD as photodetector

The growth of Pr3+ doped Na5Lu9F32 single crystals by Bridgman method was reported. The absorption spectra, fluorescence spectra, and fluorescence decay curves of Pr3+-doped Na5Lu9F32 single crystals were studied systematically. Judd-Ofelt analysis performed on the obtained crystal reveals that the Pr3+ ions are exposed to a high symmetric environment with strong degree covalency of Pr-F bond. The sharp and strong emission bands centered at 482, 523 and 605 nm were observed under the excitation of 440 nm light. The maximum emission intensity was obtained when the concentration of Pr3+ reached to～0.5 mol%. Temperature dependent measurement suggests that the green emission is less affected by temperature than the blue and red emission.

In order to meet the demand of improving the material removal rate and polishing quality of BK7 optical glass, it is proposed to improve the dispersion of the polishing fluid and prepare the polishing liquid with excellent properties by decreasing the agglomeration of the polishing fluid particles of the Magnetic Compound Fluid (MCF), improving MCF polishing performance of BK7 optical glass. Polyving Akohol (PVA), apolymer dispersant, with different mass fraction was added to MCF to analyze the particle size distribution and median particle size in the MCF polishing fluid. The effect of different amount of PVA polishing liquid on the polishing performance of BK7 optical glass was investigated. The experimental results show that when the mass fraction of PVA is 3%, the median particle size reaches the minimum of 5.854 μm, the dispersion of the MCF is the best, and the polishing performance is greatly improved. When the mass fraction of PVA is 5%, the maximum of material removal rate is 26.4×10－4g/min, and the surface roughness reached the minimum of 8.23 nm after MCF polishing 10 minutes. The addition of proper amount of PVA to the MCF, it can decrease the problem of polishing fluid particle agglomeration, improve the dispersion of the MCF, improve the Magnetic Composite Fluid polishing performance of BK7 optical glass.

By analyzing the influence of the optical system structural parameters on aberrations, a method was proposed to reduce the primary aberrations of each optical surface by optimizing the curvature to make a reasonable power distribution, which could reduce the processing and adjustment tolerance sensitivities. Using this method, a nano-star sensor optical system with a focal length of 25 mm, a full field of view of 26°, entrance pupil diameter of 18 mm and spectrum range of 500~800 nm was designed, which was a small aberration compensation system. The whole length of the system was 40 mm. The imaging quality of the optical system met the requirements. Tolerance sensitivity analysis was carried out for two optical systems. The results show that the influence of the thickness tolerance of the fifth lens on the Root Mean Square (RMS) spot radius decreases from 3.75 μm to 0.17 μm in the reasonable power distribution optical system; and the influence of the fifth and sixth element spacing tolerances on the RMS spot radius decreases from 4.36 μm and 4.74 μm to 0.25 μm and 0.18 μm, respectively. Monte Carlo analysis shows that the probability of the RMS spot radius of less than 7.59 μm is increased from 23% to 80%. The experimental results show that in the full field of view the energy concentration of the star sensor is better than 80% in the range of Φ17 μm, which meets the requirements.

From the point view of handheld/portable scenario, a dual optical fiber path is adopted as Raman optical probe structure, and the performances, types and sizes of key components are determined. Optical simulation is carried out by Zemax software. The working focal length of the incident light path is 13.5 mm, the image square numerical aperture is 0.23, meanwhile the image plane focal length of the collected light path is 13.46 mm and the numerical aperture is 0.235. The whole optical path and relative structures of the probe are simulated by SolidWorks software and TracePro software. Finally, the probe shell with overall dimensions of 50 mm × 33.5 mm × 17 mm is fabricated by computer numerical control and 3D printing, respectively. The Raman spectrum of alcohol detected by the designed probe are almost the same as that by commonly used products on markets, and has better signal performance in the wave number range from 200 cm－1 to 300 cm－1. The Raman spectrum of drugs with methamphetamine components and K powder tested by the designed probe are in accordance with the theoretical data. The experimental results have proved the practicability of the designed handheld/portable probe.

In order to reduce the complexity and development cost of the multi-band all-sky imager, a multi-band all-sky imaging optical system with no focusing and high robustness is proposed. A secondary imaging system is composed of a telecentric fisheye lens and a finite conjugate distance imaging lens of the telecentric image. The shelf-level narrow-band filter is placed at the image plane, using H-FK61 and KF2 glasses achieve full system apochromatic. The design results show that the system F number is 2.8, the band range is 427.8~865 nm, the chromatic focal shift is less than 0.048 mm, and the optical transfer functions of the eight observation channels of the system are all above 0.46, which meets the application requirements. The tolerance of filter is very loose. The surface tolerance PV is less than λ/2, the refractive index tolerance is ±0.003, the thickness tolerance is ±0.05, and the shelf-level products can meet the application requirements. Compared with the traditional scheme, the system eliminates the detector focusing mechanism and does not need to use a customized narrow-band filter, which simplifies the system and reduces the cost.

A liquid crystal lens with low driving and controllabe focal length were presented, which was driven by hollow-out driven-electrodes with high-resistance (H-r) layer to control the deflection of liquid crystal molecules according to the electric-filed distribution on the edge of driven-electrode of convention liquid crystal lens. Al-doped ZnO (AZO) transparent film, as the H-r layer of liquid crystal lens, was deposited on the surface of the layered aluminum (Al) electrode with hollow-hole arrays by magnetron sputtering and formed the top substrate with H-r layer driven-electrodes. The H-r liquid crystal lens was fabricated after the liquid crystal was sandwitched between the substrate with H-r driven-electrodes and a substrate with indium-tin-oxide common electrode. The effect of AZO H-r layer, driving voltage and working frequency on the optical properties of liquid crystal lens was studied. The experimental results show that the intereference patterns are uniformer and the focal radius are smaller when the driving voltage of 2.2 Vrms and working frequency of 130 kHz are applied to the fabricated H-r layer liquid crystal lens. In addition, the focal length of H-r liquid crystal lens can be adjusted from 4.27 mm to 2.88 mm with the driving voltages range from1.8 to 2.8 Vrms and working frequencies of 130 kHz.

To simplify and improve Radio-over-Fiber (RoF) communication systems, a kind of modulation technology based on the variation of output photocurrent with bias of PIN photodiode (PIN-PD) and unitraveling-carrier-photodiode (UTC-PD) is proposed, which is called photodiode bias modulation. By using this modulation technology, both photodetection and optoelectronic modulation can be achieved simultaneously in one PD. Based on two analytical models, the modulation bandwidth of the PIN-PD is predicted as 800 MHz at a 10 GHz RF subcarrier, and the modulation bandwidth of the UTC-PD is predicted as 18.75 GHz at a 150 GHz RF subcarrier, when the incident optical power is both 2.93 dBm. The modulation bandwidth increases with the incident optical power, when the incident light power is 12.93 dBm, the modulation bandwidth of the UTC-PD can reach 25 GHz at a 150 GHz RF subcarrier. The modulation depth is associated with the minimum value of the sinusoidal bias modulation signal.

A two-phase filtering reconfigurable optical physical unclonable function is proposed using the optical speckle. Firstly, the random and unclonable optical speckles are produced by random deviation of the spatial Brownian motion, optical interference and diffraction. Then, the mode selection and two-phase filtering methods are used to realize the reconfigurable function and reduce systematic error. Finally, the optical speckle image is acquired with the help of charge-coupled device system. After binarization and von Neumann processing, the binary data of the physical unclonable function is got with characteristics of randomness, robustness, and reconfigurable. 10 sample optical physical unclonable functions, which each sample can produce 512-bit binary data, are fabricated and tested. The experimental results show that the proposed physical unclonable function passes all National Institute of Standards and Technology randomness tests, the randomness of the physical unclonable function output is 99%, and the two-phase filter method reduces the system error about 3%.

The near field luminescence enhancement of gallium arsenide thin films was achieved by studying the local surface plasmon resonance coupling effect of gold nanoparticles. By calculating the absorption spectrum and electric field distribution of gold nanoparticles theoretically, the effects of changing the shape and size of metal nanoparticles on the regulation of plasmon resonance frequency and local field enhancement were analyzed. A near field enhancement effect of 35 times was achieved by simulating gold nanoparticles with a radius of 50 nm. Through the simulation of double sphere shape, an active way of gold particle enhanced GaAs was analyzed, that is, the coupling between dense particles, forming "hotspots" and accompanying the enhancement effect of local field. In addition, the effects of sputtering time and rapid annealing on the absorption characteristics of gold nanoparticles were investigated. The absorption peak of the nanoparticles is mainly located in the 560~680 nm band. Moreover, the red shift occurs with the increasing of sputtering time. After rapid annealing, the absorption peak of gold nanoparticles shifts blue to 510~550 nm band, forming a resonance absorption peak matching the excitation wavelength of 532 nm. Finally, the photoluminescence of gallium arsenide thin film is enhanced by 9.6 times.

An absolute radiometric calibration method based on the surface hyperspectral Bidirectional Reflectance Distribution Function (BRDF) model is proposed, which the efficiency and frequency of on-orbit absolute radiometric calibration of remote sensors are improved by getting rid of the dependence on synchronous observation of satellite overpass time. In-flight high-frequency absolute radiometric calibration verification and application was carried out with Operational Land Imager (OLI) on Landsat-8 using this method. The surface directional reflectance of the Dunhuang test site was measured by the Unmanned Aerial Vehicle (UAV) measurement system, and the hyperspectral BRDF model parameters of the Dunhuang site were inversed based on the semi-empirical kernel-driven model. Comparing the model calculated data with the measured data, the present model is proven to provide a better fit to measured data. The surface hyperspectral reflectance data of satellite observation direction calculated directly by surface BRDF model is used to replace the synchronous measurement data of satellite transit time. The high-frequency absolute radiometric calibration of Landsat-8 OLI is realized by using the reflectance basis method combined with MODIS official atmospheric data products. The relative deviation between the Landsat-8/OLI observed apparent radiance and the model calculated apparent radiance is less than 5% and the standard deviation is less than 2% in the first band to the sixth band. The result shows that the absolute radiometric calibration method based on the UAV BRDF model are in high consistency and stability with the satellite observations.

In order to evaluate the image motion reliably, a numerical analysis method was promoted for calculations of jitter transfer functions between input disturbances and output image motion. Firstly, Kistler table is applied to measure the disturbances of flywheel and precise test data of each disturbances are achieved. Secondly, a flywheel is assembled in a high-fidelity satellite prototype and jitter-affected image motion data are obtained from the prototype. Thirdly, a series of Linear System of Equations (LSE) whose variables are the transfer functions are constructed and solved with the help of harmonic data of flywheel disturbances and image motion. At last, by applying the calculated transfer functions, the evaluation of image motion of another flywheel which comes from the same product series is completed. With the reference to the test data, the evaluated image motion performs the same harmonical characteristics, the relative errors of typical responses in evaluated image motion are less than 10% and most absolute errors of rest parts are no more than 0.1 pixel. Compared with theoretic modeling method, the numerical method is faster and more reliable.