The measurement technology based on optical fiber sensor network owns the advantages of multiple measurement points, fast measurement, anti-electromagnetic interference, intrinsic safe, etc., which shows a wide application prospect in aerospace, electric power, civil engineering and other fields. The application progress of optical fiber sensing technology in aerospace field is reviewed, where several key technologies in aircraft applications, e.g.the preparation of optical fiber sensors and distributed optical fiber measurement technologies, are emphatically analyzed. As the monitoring object, the thermal protection material is integrated with the high-density weak-reflection optical fiber Bragg grating sensor, and an optical frequency domain reflection system has been built to obtain the millimeter spatial resolution under the condition of single-side heating. The development suggestions of the distributed optical fiber sensing system with high spatial resolution have also been provided to meet the needs of aerospace applications.

The aerial imaging technology based on volume holography is a new type of display technology,which has the characteristics of aerial imaging, without medium and the images being touched. Aerial imaging technology is introduced. In response to the display requirements of creating a real image, through theoretical calculations of holographic imaging, a two-step shooting optical path is designed with a focus on achieving a size of 100 mm at a height of 79.8 mmx99.4 mm real image with a field of view angle of 7.92° horizontally and 7.92° vertically.With the characteristic of floating in the air to form a real image, it can be combined with sensing technology to form a contactless operating system in the air, which provides new technological choices for developments in various industries.

The design theory, design steps and related important formula of the cut-off filter membrane of interference filter are illustrated in detail, and from the practical application, the 4.0~4.8 pm infrared penetration cut-off filter design process is expounded. Through the modern membrane design software optimization, the membrane layer performance is improved, and the filter to meet the requirements of the design index is prepared. The mean transmissivity of the infrared cut-off filter is less than 3.5% at 1.6~3.5 pm cut-off band, is more than 90% at 4.0~4.8 um cut-off band, and the filter layer can withstand temperature shocks from -190 C to 60 ℃, showing the accuracy of the design and the feasibility of the preparation process.

A low-loss UV hollow-core anti-resonant optical fiber is designed by simulation. Firstly, a theoretical model of the UV hollow-core anti-resonant optical fiber is established based on the finite element method. Secondly, the performance and loss values of the optical fiber are further optimized by adjusting the parameters of the reflective layer and air filling ratio, and controlling the light propagation and reflection using the anti-resonance effect. Finally, the finite element method is used to simulate the designed UV hollow-core anti-resonant optical fiber,which results in a minimum transmission loss of 0.003 26 dB/m at a transmission wavelength of 375 nm, corresponding to a bending loss of 0.006 25 dB/m at a bending radius of 5 cm, and a high efficiency and stable mode output.An important reference and guidance are provided for the development of high-performance simulation design of UV hollow-core anti-esonant fibers, which offers further possibilities for practical applications.

In order to reduce crosstalk and improve bend resistant performance, a few mode fiber with a depressed core and trench assisted cladding is proposed. The few mode fiber can support 7 LP modes within the wave length range of 1.36~1.56 m. The introduction of trench in the cladding makes the bending loss less than 1x10-7dB/mata bending radius of 1 cm, the effective refractive index difference between each modes is higher than 10-3.Based on the finite element method, the influences of structural parameters such as depressed core, trench on the effective refractive index, mode field area, and bending performance are analyzed. Numerical analysis results show that the introduction of trench is beneficial for reducing bending losses of higher-order modes.

An SnO2-WOs nanometer flowers coated microfiber bi-taper interferometer (MFI) for methane concentration detection is proposed and demonstrated. The tapered MFI is fabricated by fused bi-tapers method with the multi-core fiber. The methane sensitive materials SnO2-WO, is synthesized by using hydrothermal and impregnation methods. And the SnO2-WO3 material is coated on the MFI structure outsides by using the drop coating method.When the methane molecules is adsorbed on the coating material, the refractive index of the material will be changed, which will cause the transmission spectrum of the sensor changed. So, the methane concentration can be detected by measuring the wavelength shift of the spectrum. Experimental results show that the SnO2-WO3 nano-flower coated MFI sensor has large concentration detection range and high stability at room temperature. The measurement methane concentration range is 0~34%, the sensitivity is about 0.11 nm/%. The selectivity of the sensor is also studied. The responses of isopropyl alcohol, methanol, alcohol and methane are studied and compared,the results show that the sensor has high adsorption selectivity of methane, which has potential application in the field of mine gas detection and early warning.

White light interferometry has been applied to micro and nano structure 3D surface topography measurement due to its non-contact, non-damage, large range, high precision and high sensitivity. However, the measurement range is limited by the microscopic objective field. A 3D surface topography splicing method is proposed which can effectively improve the measurement range. Through the domain division of small range and high resolution white light interference pattern collected for many times, the three-dimensional topography data registration method is adopted, and the template matching algorithm is used to match the binary matrix of the image, and the surface topography of the components to be measured is effectively characterized. It is found that when different image splicing methods are used, namely up-down splicing, left-right splicing and 2&2 splicing methods, the effect of image splicing is different, and the accuracy and error are different. Among the three splicing methods, the 2&2 splicing method can effectively reduce the operation error, achieve a large range and high resolution interference pattern splicing, and has a broad application prospect in the white light interference three-dimensional topography characterization.

Large-size liquid crystal display (LCD) modules for airborne applications have the characteristics of high brightness and high power consumption. In order to reduce their dynamic power consumption, a dynamic backlight control system for large-size airborne display modules is introduced. The system adopts light emitting diode (LED) dynamic backlight control technology to improve dynamic display effect and achieve energy saving by dynamically adjusting the backlight. A detailed introduction to the hardware circuit and software design algorithm of the system is provided, and experimental verification is conducted. Results show that the system can effectively improve the dynamic display effect of the airborne display module and significantly reduce dynamic power consumption.

In order to solve the problem of small wavelength tuning range of external cavity tunable diode lasers, the transmission characteristics of Gaussian beam in the resonator are analyzed. Results show that adjusting the output beam of gain chip to a small divergence angle to achieve collimation is not conductive to expand the wavelength tuning range. For a Littman-Metcalf tunable diode laser covering 1 480~1 640 nm, a collimation scheme is proposed by adjusting the waist position to equal the length of the external cavity. The simulation results show that the tuning range of the tunable diode laser can be greatly improved by using this collimation method compared with the collimation method with small divergence angle.

In face of the fact that the layup angles of carbon fiber composites are different and the mechanical properties after molding are anisotropic, the decomposition of the materials by the method of orthogonal symmetry plane of anisotropic materials is simplified, the materials index of the main anisotropy is changed to the orthotropic index. The matching degree between the software fatigue simulation and the actual state of the equipment is improved based on the physical mechanical testing of the carbon fiber composite material sample and certain equipment is taken as a sample to carry out the software fatigue simulation and analysis.

At first, a finite element model of the radial connection structure of aircraft cabin based on the solid element bolt modeling is established. And then, a structural quality optimization design process considering the parameter sensitivity analysis step is constructed. At last, the optimal design of the aircraft radial connection structure with different cabin diameters and cabin materials is carried out, and the optimal design scheme is obtained, and the advantages and disadvantages of the performance of different cabin materials are compared and analyzed. The research results can shorten the design cycle and save the cost for the preliminary design of radial connection structure without sample strength.

As a universal component, cylindrical pins are often used in the field of machinery, which is used for positioning and connecting parts to ensure the positioning accuracy and connection strength of connecting components. The cylindrical pin and the pin hole adopt an interference fit to ensure the tightness and accuracy of connection and positioning of installed components. In mechanical assembly production application, it is particularly important to ensure pin lead-in and impact pressure. Based on the assembly of a component pin, non-standard equipment for pin press installation using a gas-liquid booster cylinder as the power source is introduced. The pneumatic chydraulic transmission device has the advantages of both pneumatic and hydraulic pressure, and is small in size, which provides power through an air pump to ensure smooth operation. Build a three-dimensional model through special software, complete the operation simulation of the system electrical circuit, and complete the overall optimization of the equipment through mathematical modeling and calculation of the overall structure and pressing force.