All-fiber Optic Current Sensors (AFOCS) which are used to measure the power supply system in high-voltage substations have incomparable advantages to conventional current transformers, so more and more attention is paid on it. The structure of Sagnac Ringlike Optic Current Sensors (SROCS) is developed on the structure of interferometric fiber-optic gyroscope. Because of the realization of gyroscope based on the technology of Sagnac interferometers, the same way to realize SROCS becomes one of the hotspots of current transformers. The basic principle and structure of SROCS are analyzed and researched firstly. The formulation of optic current sensor is launched by the establishment of optical matrix model, and then the development condition, research results and main problems are described with emphasis on the vibration stability.

A alignment method for infrared optical system of Cassegrain was introduced. The alignment of the primary and secondary mirror was finished on the optics centration error measuring instrument and the infrared eyepiece was aligned by means of metal-turning centering .Then, on the optics centration error measuring instrument, the alignment of primary and secondary mirror and eyepiece was completed. As the system has a linear detector, an external oscillating mirror was adopted. The oscillating mirror is oscillating with the fixed frequency, so the detector forms a complete picture of the target. In this way, the adjustment of the detector can be completed easily. One kind of this optical system was finished by this method. The noise equivalent temperature difference and minimum resolvable temperature different were measured and demands of system for all technique targets were met.

With the increasing demands for the capacity of fiber communication system nowadays，DWDM and L-band optical devices had become research hot spots．Moreover, multi-wavelength source has attracted more and more attention. The theory model of electro-optic intensity modulation based on the structure of Mach-Zehnder is illustrated. The output optical spectrum of broadening result is simulated and analyzed by the formulae while the microwave frequency and power are fixed. The 10 GHz, 15 GHz and 20 GHz frequency shift at 1 550 nm are obtained experimentally with a LiNbO3 waveguide. The spectrum calculated by theory agrees with the result of experimental system in real shape, and optical sidebands with equal frequency intervals are observed in the output spectrum in simulation. The third-order sidebands can be observed distinct when the frequency is 10 GHz, the modulation depth is 1.39 and the direct current bias voltage is 2.98 V. Particularly, the fundamental frequency and the first sideband obtain the same peak power means which can generate a three-wavelength optical source of excellence.

In this research, the recovery process of optical stopping effect in thin film waveguide with doping As2S8 and As2S8 is studied. Based on this, the chemical bond structures of the samples are analyzed. With the help of the theory of hybridize valence orbital and the theory of electron energy band gap, the dynamical equation of recovery process is proposed. The numerical analysis results are well matched with the experimental data, and the recovery process of optical stopping effect can be predicted by the deduction of the model. It reveals the basic nature of the experiment.

Ray tracing was used to analyze the Focal Ratio Degradation (FRD) properties of fibers, which is caused by the light transmitting in the fibers with offset and bending when we set the fibers and observe stars in astronomy. We analyzed and calculated the conditions of the fibers used in the Large Sky Area Multi-Object Fiber Spectroscopy Telescope(LAMOST) according to the parameters of the fiber cables used in the LAMOST. These works provide useful reference in this project. According to the analysis and computation, the designed aim error of fibers should be less than 32 μm at least.The least bending radii is 300 mm when the fibers are installed for observation in the LAMOST projection.

Two parallel line waveguides were formed by removing two lines silicon pillars which alternate with three line pillars in photonic crystal. Its coupling properties were investigated by use of Finite-difference Time-domain (FDTD) method. It is found that the coupling length between two waveguides can be changed significantly by turning the size of silicon pillar and background refractive index. A new liquid refractive index detection method was brought forward based on this research. Compared with normal liquid refractive index analyzer reported, the most important aspects are the fast detection and miniaturization of devices.

We report a linear extra-cavity, tunable mid-infrared, Continuous Wave (CW) singly resonant Optical Parametric Oscillator (OPO) based on periodically poled MgO-doped LiNbO3 (PPMgLN). A Nd:YVO4 laser pumped by 808 nm LDA is used as the pump source. The threshold of OPO system is only 1.09 W at 1 064 nm. A maximum idle laser output power of 346.8 mW at 3.202 μm has been achieved when the pump power is 4.55 W and it corresponds to an (only idler) optic-optic conversion efficiency of 7.6%. By shifting the PPMgLN crystal, the periods of the domain structure on the PPMgLN wafer can be changed, thus enabling a mid-infrared spectral widely tuning range of the laser output from 2.98～4.19 μm. This laser is very compact, simple and operated at room temperature.“中红外波段全固态光学参量振荡器产品研究与开发”。

A small-sized laser proximity fuse based on CPLD was designed for some small-caliber ammunitions, the common anti-interference methods used for medium-caliber and large-caliber ammunitions will not be suitable, due to the limited space and power. Analyzed the interferences of a small-sized laser proximity fuse, the major ones are: (a) the electromagnetic radiation of laser transmitter module; (b) the unstable power supple disturbs all circuit modules; (c) false targets like tree branch. Kinds of technical measures are adopted in circuit design, PCB design, optical system design, and programming to reduce their influences to ensure the necessary stability, reliability and precision. Using small-caliber ammunition as a base to develop prototyping and conduct targeting experiments successfully. The test experiments show that the power consumption is low and it can detect vertical test board (gray iron) at 5 m far away with no more than 90 mA current (25 V DC). The test results in high overload conditions indicate that the prototyping can work normally and steadily in the whole trajectory.

Calculating 1.06 μm laser attenuation coefficients usually depends on experience data or typical aerosol model.Therefore, theory calculation can not be combined with actual aerosol condition, and the attenuation coefficient precision can not be satisfied with the requirements of laser weapon. The article validates difference between experiment data and attenuation coefficient whose calculation depends on typical aerosol model by experiment of laser atmosphere attenuation in Suizhong area, namely, the aerosol model is different from actual aerosol condition. According to experiment data, analysis of function relation between aerosol number density and visibility, provides a kind of method for engineer calculation of laser atmosphere transmission simply and exactly.

To study the output mode distribution of the frequency doubling resonant in PPLN, the field distributions and beam quality M2 factor of the plano-concave resonator or dual-cavity were calculated and compared. The output fundamental modes of them with tilted Gaussian-reflectivity mirrors were simulated with Fourier transformation method and Fox-Li iterative method. The results show that the output fundamental mode of the frequency doubling external resonants is Gaussian distribution, and cavity length changes have less effect on the output beam quality. The output beam quality of the plano-concave resonator is M2=1.296, divergence angle θ=58.084 μrad, and the Dual-cavity is M2=6.930, θ= 310.56 μrad. The output beam quality of the plano-concave resonator is superior to the Dual-cavity.

The experiment of 1.06 μm laser disturbing visible CCD image system was carried out, and the phenomenon of crosstalk, crosstalk expanding, full screen saturation and black-and-white spots distributing full screen were observed. With the method of finite element analysis, the temperature rise of detector induced by laser irradiating in the experiment above was simulated. Through numeric analysis, it was found that as temperature rose, dark-current increased while pixel saturation threshold decreased. Especially, when temperature was higher than 350 K, the trend was extremely enhanced. Considering the simulation outcome and changes of dark-current as well as pixel saturation threshold, the experiment phenomenon was properly explained. Results indicated that besides photoelectron produced by photoelectric conversion, the temperature rise induced by laser irradiating and corresponding changes of dark-current as well as pixel saturation threshold was important influencing factor to saturation effect of CCD.

In oblique incidence, the multiple-cavity narrowband thin-film filter will have high polarization dependent loss. A novel 100 GHz angle-tuned thin-film filter with low polarization dependent loss based on the birefractance crystal polarization beam splitter is proposed. By modulating the incident angle and the polarization modes of the incident light, only the general thin-film filter can change its transmitting central wavelength. The stack of the multiple-cavity thin-film filter can be greatly simplified, and its cost will be reduced. This tunable filter has many advantages such as simple structure, low cost and low polarization dependent loss. The experiment shows that its tunable range can easily cover the whole C-band.

Based on the optoelectronic transformation technology and the parallel-laser-scanning inspection principle, a transmission laser scanning inspection system for diameter measurement was designed. A parallel-flat-crystal was used to make up the transmission laser scanning transmitter so that highly paralleled scanning beam can be acquired in the absence of scanning objective lens. The front data processing module and the communication module were included in the measurement and control platform based on FPGA. The incident angle was determined by the time parameter which was measured by the peripheral timing circuit. The offset between transmission beam and incident beam was calculated through the incident angle. The diameter of work-piece was then derived by simple algebraic operation. The measuring principle and characteristics of the system were discussed in details. The experimental platform was established and results show that precision requirement on assembly of the transmitter is not so higher than other systems and measurement error can be easily limited in ±0.008 mm.

To study the influence of the light source, object, measuring system and subpixel location algorithm on the sub-pixel locating accuracy, a CMOS imaging system is designed for experiment and data treatment. The results show that the stability of the source and the measuring surroundings have notable effect on the high accuracy of measurements. The improved centroid algorithm with a threshold has the same effect on de noise but can reduce the interference signal dramatically and especially with a dynamic threshold while the interference signal has the property of slight change. Choosing an algorithm appropriately according to the real object and the error distribution is the key to gain the high precision subpixel location in engineering application.

Both the analysis of phase errors which occur at the abrupt discontinuities in the profilometry based on fringe projection and the identification method are presented in this paper. The sampling effect of CCD will cause a dilution of accuracy, especially at abrupt discontinuities on the object surface. We analyze the relationship among the phase, the height and the equivalent wavelength. By viewing the phase as the argument of a vector, we find out that, CCD sampling introduces error into the measurement, and the phase is nonlinear to the equivalent wavelength. Therefore Temporal Phase Unwrapping (TPU) is introduced into the measurement to identify the abrupt discontinuities. Computer simulations and practical experiment validate the feasibility of this method. The study provides the theoretical support for the reduction of errors caused by CCD sampling.

In order to find zero Optical Path Difference (OPD) position with high precision in white light interferometry, the algorithm of spatial frequency domain analysis is studied. The phase information of the nominal center wavelength is acquired from white light interference intensity signal using Fast Fourier Transform (FFT). The phase illegibility is removed to determine zero OPD position according to the coherence peak. The Computer Generated Holograms (CGH) with a depth of 1.63 μm is measured. A continuous surface of the micro lens array tested with Frequency Domain Analysis(FDA) has a PV value of 370.99 nm and a RMS value of 62.4 nm. By obtaining the position of the zero-order white light fringe, the FDA method can be used to measure the micro surface profile.

The speed of general connected component detection algorithms was slow, and most of these algorithms needed more than one scanning. A connected component detection algorithm was presented based on Breadth First Search(BFS) with the First In First Out (FIFO) queue. The algorithm was a non-recursive algorithm, the connected component could be detected by one scanning, and the storage space and running time could be reduced. We used a particular scanning template to process each pixel, avoiding more than one scanning. The multi-core parallel processing was used to accelerate the algorithm, and it realized the truly parallel computing. With the connected regions ordered from top-left to bottom-right, a reverse merging method was proposed to simplify the complexity of region merging. The experimental results show that the detection rate has been greatly improved.

Wheels are the most important bearing parts of train, and wheel’s operation influences safety of the train’s motion. On the premise of investigating and summarizing the application and development of the tread profile's scratch detection technology at home and abroad, the paper describes a multi-channel data acquisition system using Cyclone serials FPGA as the core control module, which achieves communication to Digital Signal Processor (DSP) at the back-end. Ultimately, the field test demonstrates that the system can measure damage of the wheel tread and ensure the safe operation of trains.

Aiming at the problem of high false alarm rate or high leakage alarm rate caused by poor quality of low-contrast x-ray carry-on luggage images in airport security, an efficient two-stage x-ray image enhancement scheme is proposed in this paper. First, low and high energy images are fused with Discrete Wavelet Transform (DWT) and Independent Component Analysis (ICA) to implement the first stage enhancement. Then, the proposed Adaptive Sine Gray Level Transform (ASGT) is applied to achieve the second-stage enhancement. Experimental results demonstrate that the proposed algorithm can improve image quality effectively and outperforms other enhancement methods discussed in this paper.

Camouflage netting is usually used against monitoring and reconnaissance, and SAR pictures of different bands and polarizations can provide synergy information of targets covered by the camouflage net. By qualitative theory analysis and quantitative data analysis, the effect of different bands and polarizations on targets under the net was researched. And the pixel and decision fusion algorithms were compared. Then a multi-bands SAR target detection method was provided based on decision fusion. Improved Neyman Pearson rule: regarding the probability of target detection and effective detection ratio as performance indexes, was used to select the most effective single-band or polarization resource. Moreover, scale filter was used to evaluate per target pixel and reduce the redundant information which came from single channel. The improved algorithm and the original one were evaluated by using effective detection ratio as performance index of fusion detection algorithm. Through the experimental results, we proved that the algorithm provided can reach high comprehensive performance of false rate-detection rate.

It is difficult for conventional anisotropic diffusion filters to estimate edge pixel in noisy condition. In this paper, a new construction method for conduction coefficient was proposed, which improved the estimation of edge pixels in diffusing iteration and showed good performance for high-level noise reducing. The experimental tests were implemented on highly noised synthetic and scene images, and results proved our method excels over traditional filters in terms of variance reduction, edge preservation, and visual comparison.

The vibration of platforms would lead to the relative motion between the optical camera and the scene in the exposure time, seriously affecting the image quality. But the model of degradation may not be single. To solve the problem of image simulation degraded by complex forms of vibration with high-order and multimode, the differential image motion path degradation method based on the matrix of image motion is proposed. With this method we can have an overall consideration of both the airspace and frequency domain features of the vibration’s impact on imaging. Actually, as long as the vibration function is known, the degraded image can be simulated with an original image. And by contrast of the theoretical features and the measured features of degraded images’ spectrum, reliability of the simulation method can be validated. The simulation algorithm can control the degradation parameters accurately and flexibly and provide great convenience to the restoration of the degraded images.

Chromatic Confocal Displacement Sensor (CCDS) is now used widely for its high precise and robust property. As the key component, the objective is used to achieve longitudinal focus vibration with wavelength. The theory of CCDS is analyzed and formulae for calculating the parameters of objective are presented. With the formulae guiding, a dispersive objective was designed. To obtain large axial aberration, the objective is configured with high dispersive glass singlet and special doublet lens. And aplanatic lenses and doublet are used to reduce longitudinal aberration. The objective dispersed the focus of wavelength between 500~700 nm to 1 mm longitudinal range, and the longitudinal aberration is less than 0.6 μm. With selected spectrometer, the resolution of CCDS is no more than 1 μm, which meets the requirements of dispersive objective precision.

For the need of high-speed image processing, a mixed PCI Express switch board is presented. According to the electrical characteristics of high-speed serial communication and the CPCIE system specifications, the PCIE lanes and high speed serial image signals were transferred to the down stream slot in a group following the CPCIE switch rules. This system could advance the PCI express links and switch the optical fiber images real-timely with a single board, provided flexible access of serial fiber images in the case of ensuring high-speed PCI Express bandwidth available. Compared with the traditional system, this system has fewer cables and higher speed. The board has been used in practice.

The gain principle of EMCCD has been introduced and Total Signal-to-noise Ratio (SNR) formula has been induced based on mechanism of EMCCD noise. The sensitive detection capabilities of EMCCD which can be strongly influenced by readout noise have been weaken by electron multiplication function. It is necessary to minish the multiplication of EMCCD as much as possible to protect electron multiplying structure. CCD60 should be operated at inverted mode to obtain less total noise. This conclusion is a significant direction to EMCCD’s hardware circuits design.