With the wide application of high power Thulium-doped fiber laser (TDFL) and the rapid development of related technologies, multi-core TDFL has received extensive attention from many researchers, and the effective clad pump technology is the decisive factor to realize the multi-core TDFL high power output. TDFL is usually pumped by 793 nm laser. By continuously optimizing the double clad fiber structure at 793 nm operation wavelength, the transmitted Gaussian beam is shaped. When the core size is 6 μm, the ring size is 6.5 μm and the inner clad refractive index is 1.462 4, the hollow beam with suitable dark spot size and circular beam width is obtained finally. Using the double clad fiber pumped multi-core TDFL design, the pump light can be better absorbed by the thulium ions doping within multi-core fiber and the output laser power and pumping efficient of the multi-core TDFL at 2 μm are improved.

An improved method to control longitudinal divergence angle based on step-by-step method is proposed to obtain quickly LED small divergence angle rectangular uniform illumination at horizontal and longitudinal directions. Three optical curved surfaces can be constructed quickly through designing three contour lines. The optical system is made up of the reflective lens constructed based on optical curved surface and an adjacent reflector. Simulation results show that when the ratio of the distance between the optical source and the inner curved surface of lens and the optical source size is more than 6, the horizontal divergence angle of the optical beam is less than 1°, the longitudinal divergence angle is less than 2.6°, and the illumination uniformity is more than 0.75. It provides an effective way for optical system with small divergence angle rectangular uniform illumination requirements.

The luminous performances of remote phosphor with domed, elliptical and conical shapes under various drive currents and light intensity distributions are researched. A blue LED is used as the light source to excite YAG:Ce3+ phosphor to emit white light. Meanwhile, constant-current sources and TEC heat sink controllers are used to control LED driving current and heat sink temperature respectively. Comparing the optical and chromatic parameters of three remote packing phosphor samples with different shapes, it is found that the elliptical sample has the best optical characteristics and the highest luminous flux. Yellow-blue ratio (YBR) spatial distribution tests of the three kinds of remote phosphor are performed respectively under different currents. The domed sample shows the best YBR spatial distribution uniformity, ACCTD and ACU value are the best among three samples. Comparing to big angle, the YBR values of the three samples measured closed to 0° decrease at different levels for the phosphor layer at the normal direction of the chip far away from the light source and shorter optical path in phosphor, so the excitation effect is different from that of the big angle exit light. Based on experimental phenomenon, shapes of light source encapsulation and phosphor layer become important factors to influence light distribution. Therefore, the exit light path is optimized through changing the packing way of the remote phosphor, which is important to improve remote phosphor illumination performances and has better reference to the research on high power white light LED optical performances.

The femtosecond laser ablating CuZr amorphous alloy has been simulated using the molecular dynamics method combined with the two temperature model. The duration of laser is 100 fs and the fluence is selected from 40 mJ/cm2 to 200 mJ/cm2. At low laser fluence, the ablation mechanism of the target material is mechanical spallation. At high laser fluence, thermo-mechanical removal and phase explosion co-exist in the ablation process of the target material, and with the increase of the fluence, the phase explosion becomes the main removal mechanism. The disordering of CuZr amorphous alloy structure is analyzed by the radial distribution function. The results indicate that material atomics maintain a disordered state and no obvious crystallization is observed when the laser fluence increases from 80 mJ/cm2 to 120 mJ/cm2 during ablation process.

Based on a stacked array consisted of vertically cascaded four pairs of metal dielectric bilayers, a one-dimensional double-frequency absorber with polarization insensitive and fabrication-tolerant is designed. Simulation results show that the absorber can implement double-frequency polarization insensitive absorption based on the absorption principle of magnetic excitation resonance to TM polarization wave absorption and waveguide mode resonance to TE polarization wave absorption. Structure parameters are predicted through LC equivalent circuit and eigen equation, and the electromagnetic field distribution is analyzed to further understand the absorption principle of the absorber. More importantly, the insensitive structure of the one-dimensional absorber is independent for TM and TE polarization wave absorption, and the absorption characteristics of the absorber is less affected by the spacing distance between the neighboring stacks, which make more free and flexible in the design, make the absorber extremely simple in fabrication and have high flexibility, with covering the range of electromagnetic waves from microwave frequencies extended to terahertz. The research on the absorber is very important to the absorber development and it will have better application prospect.

A passive target localization algorithm based on airborne imaging system is proposed. The precise calculation of target location can be achieved by using airborne imaging devices. Firstly, according to the lens design parameters, the target coordinate information in the image can be mapped to the location under ideal camera model. The target space coordinate information in the camera coordinate system can be calculated by using the image view and image resolution. Secondly, the target space location information in the inertia navigation coordinate system can be calculated by using the imaging system installation location and airborne posture information. Finally, according to the latitude, the longitude and the altitude of the airborne location, the target actual location can be calculated. The experimental results demonstrate that our proposed algorithm can achieve accurate target localization in less time.

With the development of infrared detector and image processing technology, the resolution and frame frequency of infrared images become higher and higher. Moreover, the transmission bandwidth of infrared images is increasing. In order to meet the needs for the image acquisition of infrared detection equipments, an image acquisition module based on the digital signal processing (DSP) of TI Inc. and the low-cost field programmable gate array (FPGA) of Xilinx is designed. In detail, FPGA achieves the access memory of DSP through the host port interface (HPI). The Ethernet chip is configured and managed by DSP through Ethernet media access controller (EMAC) interface to realize gigabit Ethernet transmission function. The module is characterized by high bandwidth but low cost and easy to implement, which can meet the bandwidth requirements of current infrared detection equipment image acquisition.

The circuit design of Ethernet’s interface based on MPC8377 and JEM971A is described. The design problem of low signal transmission speed in application is tested and analyzed to find and analyze the fault reasons. The components in application is tested and analyzed. The faults from input and output of the hardware circuit are tested. The writing software is used to test and analyze. Printed board circuit is analyzed and tested to shoot the fault through comparing method. The fault reasons and solutions are found to obtain the correct design conclusion, which provides the valuable application design advices to the designers.

Because of the different water impurity effects on laser signal transmission characteristics, according to the impurity parameters of different seawater, the attenuation characteristics of blue-green laser in the optical channel of seawater are analyzed and the relationships between the different concentration and channel attenuation characteristics about the laser with a wavelength of 530 nm are studied. By using Monte Carlo method simulation, the transmission of laser with a wavelength of 530 nm in seawater channel is simulated, the simulation figures about different impurities concentration effect on received power are gotten. While fitting the simulation results by using Gaussian function, the relationship model of the concentration effects on the power of the receiver is obtained, so the power of any position in different seawater concentration can be achieved, and attenuation coefficient of different seawater concentration is gained, which can provide the theory evidence for underwater wireless laser communication.

According to the balancing problem of the robustness and invisibility, a new digital watermarking technology for quick response (QR) code based on Tetrolet transform and singular value decomposition (SVD) is proposed. At first, the energy information of the QR code image is concentrated in Tetrolet coefficient using Tetrolet transform. And then, the coefficient is decomposed by SVD. At end, the watermarking embedding is completed by embedding the scrambling encryption watermarking image to the singular value matrix. The simulation results show that this algorithm can effectively resist noise attacks of Gauss, salt and pepper and multiplicative. It also can resist geometric attacks of rotation, shear and translation. This algorithm can effectively improve the ability to resist noise and geometric attacks, achieve the balance between the robustness and invisibility of the digital watermarking system in the prerequisite with the image without distortion. It shows a high practicability.

Plant image extraction is the basis for determining the plant location, which is in the field of image segmentation. The image color information cannot be ignored on one hand, based on this point of view, a colored region segmentation method is proposed. Because of the large green component of the plant, it is possible to use the maximum component extraction method to realize the segmentation of the plant in the image. The method has minimum calculation and operates only on pixels. In addition, the method can not only separate the buildings and plants, but also make the image more accurate. Adaptive threshold binaryzation calculation method can be used at real time according to the brightness of the image and can be better adapted to image binaryzation processing at different light condition. The examples prove that the method is effective and reasonable.

Taking infrared imaging air to air missile as the simulation object, with basic object model (BOM) development standard, the infrared imaging guiding hierarchical structure model is designed, and the BOM system composition is introduced. The image segmentation algorithm based on the maximum distance method and the recognition algorithm for the comprehensive evaluation target are discussed. The application conditions and working process of centroid and correlation tracking algorithms are studied. According to the evaluation criteria, the infrared imaging guiding algorithm simulation evaluation system is established based on BOM, which provides a platform for the anti-jamming guiding algorithm evaluation.

An original location inspection method using the position sensitive detector (PSD) for the optic-axis parallelism of the observation and aiming system is introduced. The bend-over design of optic path compresses the big axis distance into small, reduces the size of the detection system and enhances its stability. The high precision PSD is used to detect the gravity position of light spot to simplify system structure and improve measurement accuracy.

The projective synchronization problem between the optical bistable discrete uncertain network with topology switching characteristics and the target signal is researched. The network is configurated separately and suitably and the active control method is used to design a suitable controller. A special Lyapunov function is constructed further to make the network to achieve synchronization in a short time and the update rules for parameter identification are obtained. Numerical simulation is carried out to verify the effectiveness of the designed controller.

The research on the network synchronization from non-time-varying to the time-varying situation is expanded. The problems of parameter identification and outer synchronization of the optical time-varying network are researched. Based on Lyapunov theorem and Lipschitz condition, the self-adaptive laws of feedback strength and coupling matrix elements are obtained. Taking the acoustic-optic hybrid optical bistable chaos system as a simulation example, the correctness of theory analysis is verified by simulation results.

During laser propagating in atmosphere, the power density distribution in far field changes greatly relative to laser exit due to the turbulence affection, the thermal blooming and extinction. Accurate measuring important parameters such as laser facula energy, beam quality and centroid shifting in the far field are important to analyze laser atmospheric transmission effect. The measurement error and causes in detector lattice array method laser far field characteristic measurement technology are discussed. The errors are analyzed quantitatively and an effective method to reduce the measurement error is proposed, which provides the basis for further exploring the interaction law between laser and atmospheric medium.

The smoke interference in passive interference and the basic knowledge of smoke are summarized. The generation and the jamming principle of smoke are analyzed. The distribution function of the smoke particle size and Bill Lambert law of smoke extinction are introduced. The extinction characteristic of the graphite particles to 1.06 μm and 10.6 μm wavelength laser is analyzed. Simulation results show the changing laws of mass extinction coefficient, the transmittance of smoke, which is composed of graphite and copper powder particles, smoke thickness and concentration as particles radius changing.