Because the measurement accuracy of the diffuse radiation photoelectric sensor in the photoelectric insolation meter seriously affects the accuracy of the solar irradiance measurement， in order to reduce the scattering error，more accurate simulation of the diffuse radiation is needed for indoor calibration. Through the linear correlation analysis between the radiation attenuation rate and each meteorological factor in the day-by-day time scale， the daily horizontal solar scattering radiation model in Changchun area is obtained after multivariate linear regression fitting. The radiation attenuation caused by the scattering of water vapor and dust is simulated in the indoor verification system， and the indoor scattering environment simulation chamber is designed. The results show that the fitted values of the daily scattered radiation in the horizontal plane are well matched with the measured values. The measured values and fitted values are evenly distributed on both sides of the fitted line， and the correlation coefficient （R2） is above 0.8， indicating that the scattered radiation model has a good effect.

In order to improve anti-bending property and keep the similar model field diameter of G 652， a single-mode， small-size， anti-bending fiber by designing the structure of the optical fiber preform with depressed cladding is proposed. The outer diameter of the fiber is 180 μm， the mode field diameter reaches 9.1 μm， the macrobending loss of the fiber at 1 550 nm is less than 0.4 dB and the long-term environmental performance is not larger than 0.03 dB/km. The cabling results show that the size of the cable can save 44% by using this optical fiber. The optical fiber cable could be used for crowded and narrow channels.

In order to solve the problems of high peak-to-average ratio of traditional orthogonal frequency division multiplexing technology， complex-valued signal structure cannot be directly applied to intensity modulation direct detection system， Lifting Wavelet Transform （LWT） is applied to Orthogonal Frequency Division Multiplexing （OFDM）. The orthogonal wavelet basis is selected as the subcarrier. By predicting and updating the signal， the high and low frequencies of the signal are separated. Combined with the multiple reflection channel model of Visible Light Communication （VLC）， the DCO-LWT-OFDM system model was established， and the iterative decomposition and renewal reconstruction formulas of LWT-OFDM signals were deduced. The performance of the DCO-LWT-OFDM system was simulated and verified by experiments. Simulation results show that in a 4 m×4 m×3 m indoor space， when the bit error rate of the system is 10-4， the performance of the DCO-LWT-OFDM system is about 5 dB higher than that of the DCO-FFT-OFDM system， and the overall efficiency is improved by 70%. When the system peak-to-average ratio is 10 dB， the value of complementary cumulative distribution function of DCO-FFT-OFDM system is close to 10-1， and the value of complementary cumulative distribution function of DCO-LWT-OFDM system is 0. In the experimental verification， 1 W LED lamp beads were selected to build the point-to-point DCO-LWT-OFDM VLC system on the optical guide， the transmission distance was 20 cm， the system modulation error rate was 11.4 dB， and the reliability could reach 10-4. This paper provides an effective way to improve the transmission rate of visible light communication， reduce the bit error rate and restrain the system PAPR.

A method of fiber Bragg grating time-division multiplexing intensity demodulation based on Sagnac fiber ring is presented. The time-multiplexing sensing system， consisted of the several FBG gratings with the same central-wavelength， can demodulate the signals by observing the intensity changes of the output spectrum of the FBG gratings. In the signal processing module， the wavelet analysis and Gaussian simulation algorithm are combined to demodulate the system signal together. The experimental results show that the signal-to-noise ratio of the system signal is increased by about 36% from 8.06 dB to 11.7 dB， which effectively improves the anti-interference ability of the system and the detection accuracy for the external parameters. The proposed method effectively increases the number of fiber Bragg grating sensors in the demodulation system with less cost and can be widely applied to various sensor systems or parameter detection systems.

pulse width modulation technology is proposed. Bilevel pulse width modulation is analyzed in terms of bandwidth requirement， junction capacitance and error performance， and compared with non return to zero on key modulation， pulse position modulation and digital pulse interval modulation.The results show that the two-level pulse width modulation and the non-return-to-zero on-off keying modulation have the same time slot error rate， but the additional power consumption is only M/2 of the non-return-to-zero on-off keying modulation， and M is the modulation order. Although the bilevel pulse width modulation requires higher signal-to-noise ratio compared with pulse position modulation and digital pulse interval modulation， the additional power consumption is only half of that of pulse position modulation and digital pulse interval modulation， and the bandwidth requirement is also less than that of pulse position modulation and digital pulse interval modulation， it has great advantages in power and bandwidth sensitive visible light communication system.

The optical loss caused by Waveguide Sidewall Roughness （SWR） of Silicon-on-insulator （SOI） is one of the restrictions to the adoptions of silicon photonic integrated circuits. In this paper， the anisotropic SWR of an SOI waveguide is measured by Conformal Laser Scanning Microscope （CLSM） and with introduction of a Three-dimensional （3D） anisotropic SWR， the traditional theoretical model for defining the Optical Propagation Loss （OPL） coefficient， so that a more accurate theoretical model is obtained. Numerical simulations show that the waveguide structure determined Correlation Length （CL） and the SWR have the synchronous effects on the OPL. Fabry-Perot （F-P） cavity modulation resonance output is used to accurately measure the OPL， and the measured values are agreeable with the simulation result， implying the improved model has more believability. For a waveguide with a 4 μm width， when the average horizontal and vertical SWR values are 22 nm and 23 nm， respectively， the simulation results of OPL coefficient for both TE- and TM-mode are 4.5~5.0 dB/cm， while the experimental result is 4.9 dB/cm. Hence， the outcomes and conclusion obtained are very valuable to be referred for research and development of SOI waveguide devices.

To solve the measurement problems of fiber-optic strain sensors caused by temperature sensitivity， a hybrid temperature-strain dual-parameter based on fiber Bragg grating and multimode interference of hollow core fiber was proposed. The sensor is composed of a hollow core fiber fused between two single mode fibers， and the inner diameter of the hollow core fiber is smaller than the core of the single mode fibers， besides， on the core of one single mode fiber， near the fiber end， a fiber Bragg grating is pre-written. The hollow core fiber has a length of centimeters， in which， the optical wave is propagating in a multimode form. Combining the different responsitivities of the hollow core fiber and fiber Bragg grating to the temperature and the strain， the two parameters can be simultaneously demodulated by solving of the dual-parameter coupling matrix， and the problem of temperature-strain cross sensitivity of a single fiber Bragg grating or hollow core fiber sensor can be effectively solved. A hybrid fiber Bragg grating- hollow core fiber sensor was fabricated by using of a fiber Bragg grating with a center wavelength of 1 550.172 nm and a hollow fiber of 2.5 cm long and inner diameter of 5 μm. The experiment on the strain and temperature measurement shows temperature sensitivities of 10.530 6 pm/℃ and 1.802 1 pm/℃， strain sensitivities of 0.720 7 pm/με and 1.243 2 pm/με from the hollow core fiber and fiber Bragg grating respectively.

A polyaniline film micro-nano optical fiber liquid hydrogen ion concentration probe is proposed， and the hydrogen ion concentration sensing characteristics of this fiber probe are investigated. The sensing part consists of a single-mode fiber， a small-core-diameter fiber and a single-mode fiber pair fusion spliced together， and polyaniline material is coated on the small-core-diameter fiber as a sensitive film. Firstly， a theoretical analysis of the sensing principle of the fiber optic probe and the structure change mechanism of the polyaniline main chain was conducted. Then， the effect of different film thicknesses on the sensing characteristics of the fiber optic probe was verified and analyzed by hydrogen ion concentration sensing experiments. Finally， experimental interference tests on the change of liquid refractive index were completed and the response-recovery time and stability performance of the probe were evaluated. The experimental results show that the main chain structure of polyaniline changes under the action of hydrogen ions. The interference spectrum of the fiber optic probe drifts in the short-wave direction with the increase of hydrogen ion concentration， and the detection range increases with the rise of polyaniline film thickness， while the sensitivity and linearity decrease significantly. The sensitivity of the fiber optic probe is -15.74 nm/mol/L for the hydrogen ion concentration range of 10-6~10-1 mol/L， and the response and recovery time are 25 s and 35 s， respectively. The experiments verify the change of polyaniline film’s optical properties after reacting with hydrogen ions and provide a new method for liquid hydrogen ion concentration detection. This fiber optic hydrogen ion concentration probe also has the advantages of high concrete film strength， simple fabrication， and low cost.

In order to realize dynamic and reconfigurable optical chaotic logic operations， a specific technical scheme based on Vertical Cavity Surface Emitting Laser （VCSEL） feedback by its own light and linear electro-optic modulation effect has been proposed. The normalized injection current is modulated as logic input， the transverse electric field is modulated as control signal， and the logic output is demodulated by the difference between the average value and the threshold value of the x-polarized light intensity from the output of VCSEL. By transforming the logic operation relationship between control signal and logic input， the system can switch freely among basic logic operations such as NOT， AND， NAND， OR， NOR， XOR and XNOR. When the code width is 600 ps and the noise intensity is as high as 2.75×109， the success probability of the logic operation still equals 1， indicating that the system has good anti-noise performance. And when the noise intensity equals 2.5×109， the success probability always equals 1 if the code width is at least 579 ps. The above results have great reference value for the development of fast and stable combinational logic operation devices.

Aiming at these problems of unclear targets， unobvious details， and lower resolution of images captured by imaging equipment under foggy conditions， an image dehazing algorithm based on atmospheric veil constraints and piecewise adjustment was proposed. Firstly， basic unequal relation of the atmospheric veil was mapped to plane model of square and its inscribed circle to obtain the constrained initial atmospheric veil. Then saturation approximation was used to get a rough atmospheric veil to blur the edge information. Meanwhile， gradient constraint was also introduced to detect the edge cost， which was utilized to correct initial atmospheric veil. In order to improve the distortion of images with close region and the incomplete defogging of images with distant region， an adaptive piecewise adjustment function was proposed to optimize the atmospheric veil. Finally， a clear image was obtained by the restoration module. Experimental results show that the proposed algorithm can be applied to all kinds of images， and has better defogging effect compared to some classic algorithms。It not only maintains the original images'characteristics， but also obtains the restored image with bright， clear and natural colors， and has advantages in various indicators.

Limited by industrial design thoughts， the traditional optoelectronic imaging technique has already reached its performance limitation. So that it is difficult to meet the increasing application demands in the information era. The Computational Imaging Technology （CIT） is the inevitable development of the information era. By deeply coupled with mathematical calculations and signal processing in the process of information acquisition， transmission and interpretation， the bottlenecks in physical information obtaining， modeling and solving are effectively broken by CIT. And the qualitative improvement in dimensions， scale and resolution of information are achieved. Although CIT is rapidly developing， its research layout is fragmented and decentralized， and there is no systematic system to lead the technology development. Therefore， in this paper， the concept and connotation of CIT are condensed， and the CIT system is established. Furthermore the basic commonality problems and key technologies to be solved are analyzed， especially the problem of nonlinear imaging model. The four typical imaging requirements of distance， resolution， field of view and system size are analyzed. And the corresponding key issues of super-large aperture imaging system， imaging beyond diffraction limit， bionic optics， interpretation of light field information， computational optical system design and computational detector are expounded. A global perspective is provided in this paper for related researchers to better promote the technology development and application.

In order to solve the problems of poor imaging quality， complex structure and large volume of existing dual-band common aperture cameras， a visible/long-wave infrared dual-color optical system was proposed. Simultaneous imaging is achieved by sharing the front-end reflection structure in the two bands and adding a dichroic beam splitter on the back of the main mirror， thereby ensuring the compactness of the system structure. The influence of the dichroic beam splitter on the infrared band imaging was analyzed in detail， as well as the influence of different angles of the dichroic beam splitter from vertical direction. The correct system of long wave infrared band and the image plane were eccentrically processed by -2.39 mm， so the image quality of the infrared band was greatly improved. The validity of the analysis conclusion was verified by the field test imaging. The results show that the system has loose tolerances， simple structure， and a few optical components. This system has the advantages of easy processing， installation， and strong engineering feasibility， which can effectively improve the target detection and recognition capabilities of the camera.

An single fiber scanning endoscopic imaging system was studied in this work. A single mode fiber is driven by a piezoelectric tube with a diameter of 1 mm. The light from the fiber illuminates the target area along spiral lines， while the scattered light is collected to build an image. It is known that the precise control of the fiber movement is significantly important to the imaging quality. Researchers have found that the fiber should return back to the origin after it finished the spiral scan. Since the system can not work for imaging during the fiber return period， it is important for the scanning fiber to retreat to the origin as quick as possible. This is the key point to improve the imaging efficiency. At the same time， the residual vibrations have a great influence on the imaging quality of the subsequent scan， especially at the central area. In order to address the above problems， a theoretical mechanical model was established to describe the fiber scan. And the forced vibration behavior was analyzed by solving the equations. Then an active braking scheme was proposed to stop the fiber damping by applying appropriate voltage signals to the PZT tube. The fiber braking simulations based on finite element analysis also confirmed the feasibility of the active braking. Finally， the actual experiments show that the fiber scanning imaging efficiency was improved from 0.629 to 0.897， an increase of about 1.4 times， by optimization of the braking signal. Simultaneously， the image distortion at the central area disappeared and the imaging quality was also improved. This study should be helpful for the ultra-fine multi-modal endoscopes， OCT， and industrial endoscope detection fields.

By analyzing the relationship between the correlation coefficient of adjacent subsets and the quality of speckle patterns， a new speckle quality assessment parameter with a fixed range called mean adjacent zero mean normalized cross correlation is proposed， which can be used to assess the quality of single speckle pattern. By comparing the proposed mean adjacent zero mean normalized cross correlation， Shannon entropy and mean intensity gratitude， the stability of the proposed method is founded. The experiment results show that as the mean adjacent zero mean normalized cross correlation increases， the mean error and standard deviation in the displacement measurement decreases， and the quality of the simulated speckle pattern become better. When the maximum mean error of the speckle pattern in the displacement experiment is 0.01 pixel， mean adjacent zero mean normalized cross correlation is stable at around 0.90， while the other parameters vary greatly. These results prove that mean adjacent zero mean normalized cross correlation is effective and more suitable for quality assessment of single speckle pattern compared with other quality assessment parameters.

In the technology of particle size measurement based on forward light scattering， the inversion algorithm is one of the key issues affecting the accuracy of the measurement results. As a relatively new adaptive global optimization algorithm， genetic algorithm parameters optimization and objective function design determine the accuracy of inversion results of particle size distribution. In this paper， the setting of relevant parameters of genetic algorithm is discussed， and the numerical simulation results show that the algorithm is effective in the inversion of the particle size distribution of polydisperse particle system. The measurement and inversion calculation of polystyrene standard particles size distribution were carried out. The results prove that the optimized genetic algorithm which the genetic iteration is 3 200， population scale is 50， crossover operator is 0.7， mutation operator is 0.002 and the weight coefficient of fairing factor is 1.5×10-5 has good stability and noise immunity， and can effectively reconstruct the particle size distributions.

According to the simulation results of cloud polarization radiative transfer， the water cloud with polarization rainbow characteristics is selected as the experimental target to test the space environment adaptability of key polarization parameters. On the basis of the characteristics of polarization imager directional polarimetric camera， the large area water cloud is identified by cloud phase state. The relative transmittance and polarizability parameters are verified according to the polarization radiation model of the instrument by using the measurement data of different polarizing directions of water cloud. The experimental results show that the change of relative transmittance is less than 0.2%， the variation of polarizing degree for optical lens is less than 0.01， and the instrument state is stable. At the same time， the ability of polarization imager to identify cloud phase state by cloud polarization characteristics is verified. The methods and test results provide reference for on orbit detection and calibration of polarization imager， and provide basis for inversion of cloud products using multi angle polarization data.

Based on the wave effect of light wave， the optical path matching waveguides， array waveguide gratings， phase modulators and multimode interference couplers are designed by using the beam propagation method. On this basis， the coupling characteristics of the photonic integrated device are analyzed and calculated， and a complete photonic integrated chip is designed. Through the analysis， research and optimization of each module of the photonic integrated interferometry system， an electronic prototype of the photonic integrated interferometry detection system is designed. The results show that the minimum loss of the designed photonic integrated device is 0.07 dB， and the loss of the photonic integrated chip is 7.46 dB. When the equivalent aperture is 110 mm and the system height aperture ratio is 1∶4， the electronic prototype of the photonic integrated interference detection system has the technical indexes of 0.5 ° field of view and 5 m spatial resolution at 100 km.

A 1×8 optical splitter integrated chip with channel monitoring function was fabricated by integrating Y-branch with deep etched Bragg grating structure. The integrated optical chip after coupling and packaging realizes stable optical signal transmission and monitoring function at the same time in the channel. The central wavelength range of 8-channel reflectance spectrum of the integrated optical chip is 1 597 nm~1 639 nm， with an interval of 6 nm. The maximum of 3 dB bandwidth is 0.67 nm， and the minimum of channel reflectance is 88.24%. The average insertion loss of 8 channels is 11.92 dB and the output uniformity is 0.19 dB in the wavelength of 1 550 nm. The integrated optical chip designed and fabricated in this study has simple structure and high integration， which can be widely used in the construction of fiber to home and other optical network transmission， and realize the function of real-time monitoring of network link status.

To solve the problem that the integrated optical waveguide electric field sensor can not directly respond to the DC electric field， based on the basic principle of the field milling electric field sensor， a DC electric field sensor composed of a DC motor， a shield electrode， an integrated optical waveguide Mach-Zehnder Interferometer （MZI）， and an induction electrode is designed. Its volume is 87.5 mm×58.5 mm×17.5 mm. The working principle of the integrated optical waveguide DC electric field sensor is derived and a three-dimensional simulation model of the sensor is constructed using the COMSOL software. The simulation results show that the electric field intensity on the sensing electrode changes periodically with the rotation of the shielding electrode. A DC electric field experimental measurement system is established to test the dynamic range of the integrated optical waveguide DC electric field sensor. The results show that the minimum measurable electric field of the sensor is 5 kV/m， the maximum measurable electric field is greater than 140 kV/m， and the linear correlation coefficient is 0.995 1， which is suitable for DC electric field measurement.

This work achieves a variety of wavelength output modes in the same laser by analyzing the energy level lifetime and thestimulated emission cross section. The laser realizes the result by the regulation of the pump pulse mode without any tuning components in the cavity and does not change the output coupling transmittance.The laser modes include： 1.06 mJ single-wavelength 2 699 nm laser mode， 1.25 mJ single-wavelength 2 803 nm laser mode， alternate sequence pulse mode with dual-wavelength of 1.06 mJ 2 699 nm and 0.86 mJ 2 803 nm， alternate sequence pulse mode withdual wavelength of 1.06 mJ 2 699 nm laser and 1.35 mJ 2 830 nm.The research in this paper is expected to be the laser source of the differential absorption radar for measuring the concentration of organic matter， enabling a single detector to achieve differential measurement， while greatly simplifying the detection system of differential absorption radar and reducing costs.

A switchable multi-wavelength erbium-doped fiber laser based on a microfiber Sagnac loop is proposed and experimentally demonstrated. The microfiber Sagnac loop comb filter is fabricated by inserting a 5.5 cm polarization maintaining fiber between two outputs of an optical microfiber coupler with a waist diameter of 5.68 μm. The filter is fused into the fiber ring cavity and the four-wavelength output laser is realized by adjusting the polarization controller. In addition， the output of single-， dual-， triple- wavelength laser can be switched， and the outputs interval of dual-， triple-wavelength are tunable. The experimental results show that the 3 dB linewidths of laser output spectra are less than 0.027 nm and the side-mode suppression ratio are more than 40 dB， up to 58 dB. When the fiber laser operates at triple-wavelength， the wavelength shift and peak power fluctuation are within 0.028 nm and 0.9 dB in one hour. The laser has stable output and good monochromaticity， which can be applied in fields of wavelength division multiplexing and all-optical communication systems.

Aiming at the difficulty of achieving critical coupling conditions for aluminum nitride microring resonators， an aluminum nitride bending-coupled microring resonator is designed and prepared. Through the analysis of the coupling coefficient formula of the microring resonator， the advantages and disadvantages of various solutions to improve the coupling strength are respectively explained. Finally， a curved coupling zone structure is selected to enhance the coupling strength， and a solution to achieve critical coupling conditions under a wide coupling gap is obtained. A high-quality aluminum nitride single crystal film is grown on a sapphire substrate. Conductive glue is used to overcome the non-conductivity of the material. The electron beam exposure system is used to make the bending angle of 40°， the coupling gap of 0.190 μm， and the waveguide width of 0.41 μm. The microring resonant cavity is patterned， a number of aluminum nitride etching parameters are analyzed and optimized， and the pattern is finally transferred to the aluminum nitride layer to obtain a curved coupled aluminum nitride microring resonant cavity with uniform coupling gap and flat sidewalls. This research provides a reference for the selection of critical coupling conditions for aluminum nitride microring resonators.

A laser-diode pumped Nd：YVO4 and Nd：YAG single-longitudinal-mode 589 nm laser is presented. The fundamental waves of 1 064 nm and 1 319 nm simultaneously oscillate through an L type composite resonator. Through intracavity sum-frequency-generation in a KTP crystal （cut at type II phase matching），the single longitudinal mode 589 nm continuous wave is obtained by a birefringent filter which is consisted of a Brewster plate and the KTP crystal. The losses of S- and P- elements of the two fundamental waves are calculated by Jones matrix method. The losses of the first sub-longitudinal modes for 1 064 nm and 1 319 nm are 0.5% more and 2% more than their peak transmission modes respectively. Based on the above mentioned， a single-longitudinal-mode 589 nm laser is realized in experiment. The maximum output power is 58 mW， the amplitude fluctuation is less than 0.36%， and the line width is about 30 MHz. The results show that the birefringent filter technology is effective for single-longitudinal-mode double-wavelength oscillation and sum-frequency-generation lasers.

In theory， the tuning characteristics including tunable range， spectrum， energy and pulse width were simulated under different pump power， volume Bragg grating central diffraction efficiencies and spectral widths by setting up a rating equation model including volume Bragg grating wavelength property. A laser diode pumped Nd：YAG/Cr4+：YAG laser with a volume Bragg grating as output coupler was set up. The laser wavelength， linewidth， energy and pulse width were measured at different volume Bragg grating temperatures and pump power. The experimental results and theoretical results are in agreement. At the repetition rate of 10 kHz， pump pulse width of 40 μs， pump peak power of 10.7 W， tunable range from 1 063.77 to 1 064.48 nm is obtained. When the volume Bragg grating temperature is 50 ℃， output energy of 109.5 μJ， pulse width of 1.71 ns， wavelength of 1 064.432 nm， linewidth of 38.3 pm， M2 factor of less than 1.2 is achieved. The investigating results can be a reference of volume Bragg grating application， spectral analysis and design of laser.

A bionic integrated navigation method of polarized light/binocular vision is proposed to realize the low-cost， high-precision， strong robustness and completely autonomous navigation for intelligent mobile robot under complicated disturbing environment. Firstly， based on graph-based optimization， a tightly-coupled navigation algorithm is designed. By constructing the optimization function， the data of polarization sensor and binocular vision sensor are fused. Then， the experimental platform of the bionic integrated navigation method is built. Finally， the performance of the bionic integrated navigation method is tested through the outdoor vehicle carrying experiment， and compared with the traditional vision algorithm. The results show that the heading angle accuracy is improved by 38.9% and the position accuracy is improved by 8.9% compared with the traditional vision algorithm. The proposed method can reduce the heading angle error of vision algorithm and improve the robustness. Moreover， the bionic polarization sensor has the advantages of good real-time performance and strong anti-interference ability， which can meet the accuracy and reliability requirements of outdoor ground carrier navigation. The proposed method uses two kinds of bionic navigation methods， which make comprehensive use of the advantages of biological navigation.

The sensitivity of the Fabry Perot hydrogen interferometer based on Pt-WO3 is greatly improved by using isopropanol with high thermal optical coefficient and parallel connection structure. The isopropanol cavity of the sensor is composed of a hollow fiber with an aperture of 126 μm and a single-mode optical fiber coated with silver film on its end face. The results of hydrogen sensitivity test show that the sensitivity of the interferometer in the range of 0~2% （vol%） hydrogen concentration is 1.746 4 nm/%， fast response and good reusability. Two interferometers with small cavity length difference are connected in parallel through a 2×2 coupler， and the sensitivity is amplified by using the optical vernier effect. The combined sensor has a high hydrogen sensitivity of 15.729 3 nm/% and the two interferometers can achieve temperature self compensation， which greatly reduces the temperature cross sensitivity.This research provides a useful exploration for the preparation of hydrogen sensors with high sensitivity， low cost and wide application range.