Polarization modulation-quadrature phase shift keying (PM-QPSK) modulation technology and coherent detection technology are used to realize the long distance transmission for 40/100 Gb/s optical module. Coherent detection in conjunction with advanced PM-QPSK modulation formats is a main research field 40/100 Gb/s-long haul transmission since such scheme can achieve higher spectrum efficiency than conventional direct-detection systems. The re-emergence of coherent detection is attributed to the advanced development of high-speed analog-to-digital converters (ADC). High-speed ADC samples mixing frequency of baseband signal, and realizes coherent reception by digital signal processing (DSP) chip working in a digital balanced way. Digital signal processing chip can realize timing recovery, signal recovery, polarization and polarization mode dispersion (PMD) tracking, and the dispersion compensation.

For the improvement of optical performance monitoring in transparent and reconfigurable optical networks using artificial neural networks trained with eye-diagram parameters, radial basis function artificial neural network models to simultaneously identify three separate impairments that can degrade optical channels, namely optical signal-to-noise ratio, chromatic dispersion, and polarization-mode dispersion, are developed. The neural networks are trained with the parameters derived from eye-diagram as inputs and the tested levels of concurrent impairment as outputs. They are optimized by hierarchical particle swarm optimization method. In the process of network optimization, the particle swarm inclines to small scales and small errors by choosing proper fitness functions. Finally, the prediction of levels of concurrent impairment drawn from the optimized models is realized by simulation experiments, and a better performance compared with those based on backward propagation artificial neural network models under the same testing circumstances is obtained.

Method of double optical paths with a reference arm is applied to design a novel photoelectric conversion card to restrain or eliminate the adverse influences induced by the instabilities of light source, other active and passive apparatuses. Under the temperature of 26 ℃～28 ℃, the short-term instability of less than 0.0702% and measurement precision of better than 0.1% are obtained.

By exploiting the low reflectivity of low-Bragg-reflective fiber grating, the distributed optical fiber sensing scheme based on identical-low-Bragg-reflective fiber gratings is proposed, theoretically analyzed and experimentally studied. The demodulation technology named "optical wavelength time-domain reflection", which utilizes the optical power variation of reflected sensing signal in both time domain and wavelength domain, is adopted. The influence of reflectivity of fiber grating, interval between adjacent gratings and transmission loss of delay fiber on the multiplexing capacity of the sensing system are also discussed. Results demonstrate that this sensing scheme can increase the multiplexing capacity of sensing system effectively, implement multi-point measurement and reduce the cost of signal demodulation. Experiments on this scheme are conducted to prove its feasibility. Four fiber Bragg gratings (FBG) with the reflectivity of 6% are multiplexed in this system, which agrees with the calculation result. The resolution of 0.12 ℃ for temperature measurement is obtained.

Polarization properties and propagation characteristics of polymer photonic crystal fibers (PCFs) with elliptical air-holes and hexagonal structure are investigated by using the full vectorial plane wave method. The results show that the birefringence of the fiber is induced by asymmetries of the cladding. The modal birefringence of a PCF is 5.312×10－2 at the elliptical ratio η=3.0. The numerical results show that the modal birefringence of PCF is three orders of magnitude higher than the conventional polarization-maintaining fibers (PMFs). Moreover, by adjusting the elliptical ratio of cladding, we find the optimized design parameters of the fiber with birefringence. Zero walk-off point occurs at a wavelength longer than that of convention elliptical PMF. With increasing elliptical ratio, the walk-off curve and zero walk-off point would shift towards the long wavelength region. The occurrence of zero walk-off point can efficiently restrain the first-order polarization mode dispersion.

A turbulence-degraded image blind restoration method called ADRL-IBD using the accelerated and damped Richardson-Lucy (ADRL) algorithm is proposed. The ADRL algorithm is based on damped Richardson-Lucy algorithm and vector extrapolation acceleration technique. The observed image or the physical model of long exposure atmospheric turbulence optical transfer function is used to obtain the initial point spread function (PSF), and threshold segmentation technology is used for getting reliable support domain of the target image. The support domain restraint of image is exerted at each iteration. The restored images of simulation data and real turbulence-degraded data show that the iterative blind deconvolution (IBD) method based on Richardson-Lucy algorithm is better than the IBD method based on Wiener filtering, and ADRL-IBD. Compared with RL-IBD algorithm, it has better performance suppressing noise, greater convergence rate, and better restoration result.

The technique, method and workflow of building 3D model through the use of 3D laser scanning system to acquire point cloud data are presented. The point cloud data acquirement process and the combination of RiSCAN PRO software and Geomagic Studio software to build 3D model are discussed. The original measurement data (noise elimination, smoothing, data registration, target object extraction and so on) are processed to get the exact and full facet information of the target, and then a triangular mesh model is built for the target. Finally, through texture mapping done by using photos taken in the data acquirement process, the real 3D model of the target object is got. The experiment shows that the point cloud acquired by 3D laser scanning system can be effectively dealt with and the 3D model can be achieved via the technique mentioned above.

Arc discharges accompany with ultraviolet (UV) radiation. By detecting the radiation intensity of arc discharge the damage degree of arc to electrical equipments can be predicted. The mechanism and characteristics of arc are analyzed. According to the arc mathematical model, detection methods of arc radiation and characteristics of discharge pulse caused by spicule and metal fracture are studied. A detecting system based on channel photomultipliers is designed to capture arc. The UV radiation intensity at different distances is measured as a judgment basis of arc discharge degree. The improvement of detection effect by using light guide and light filtering modules is illustrated. The results show that the system can detect weak UV light with high sensitivity and linearity, and realize on-line monitoring of weak UV light.

The toxic components concentration of the exhaust gas of DF chemical laser in the working environment is analyzed. By applying the Gaussian normal equation of gas diffusion, a gas diffusion model is established under the experimental conditions to calculate the wind speed under different gas concentrations. Based on temporal and spatial distribution of the concentration of pollutants, the sampling points are selected, and the atmospheric sampling of trace fluoride method is developed. The gas under different conditions in different regions are measured. Then the experimental data are analyzed and compared with the national standard. The results show that, after the exhaust gas of DF chemical laser is expelled into the atmosphere, toxic ingredients in their working environment have some residue, but the concentration is in the security permitted range.

ABCD matrix mechanism is used to analyze and design laser resonators. In order to obtain a general method for programming, all elements of the matrix are considered as complex. Meantime, the beam quality factor M2 and the index of media are also considered. Based on Visual Basic programme language, a resonator software is developed. It can be used to analyze and design stable standing cavity, stable travelling cavity, unstable standing cavity, unstable travelling cavity, phase conjugate cavity and beam transmission and so on. One can add or delete optical elements at will. In addition to one general complex element, eighteen elements can be combined for resonators and beam trasformation. When tilted elements are inserted into optical path, the beam parameters of three planes such as ideal, tangential and sagittal are provided for comparison. Tolerance of thermal lens and optical length etc. can be optimized by dragging the button in the software easily. Cavity parameters such as stability condition, beam waist radius, beam waist position, beam radius at any position can displayed or output in certain file formats.

In order to improve the laser energy efficiency and beam uniformity in excimer laser refractive surgery, a novel laser beam shaping and homogenization system based on double lens array and a converging lens is designed. The prototype is evaluated by paraxial optics over a range of system parameters. A linear relationship is observed between the size of focusing laser spot and the spacing of double lens array. The overall length of the component can be changed by adjusting the distance between the lens array and the converging lens without affecting the final form of focusing spot. Ray tracing simulation method demonstrates the uniform square focusing spot on the back focal plane of the converging lens, and the change process of the focusing spot size depending on the spacing of double lens array. The impact of defocus on spot size and energy distribution is also analyzed. This beam shaping and homogenization system can meet with the quality requirements of focusing laser spot for excimer laser refractive surgery.

The research of clamping modes to large aperture KDP crystal and influence on surface figure by different clamping modes are done. Utilizing ANSYS the finite element model to simulate the obverse clamping and the flank clamping of KDP crystal, has been founded. KDP surface figure acted by flankly distributed load, equal flank two-point load and unequal two-point load is researched, and the conclusion shows that the whole load amout is a key factor to surface figure. KDP surface figures both in ideal state and in actual state have been discussed, and the conclusion that artifactitious errors for obverse clamp are a key factor has been obtained. The theoretical project has been acquired to minish the effect on artifactitious errors.

The biggest challenge of laser forming technology is how to fulfill the requirements of the workpiece shape and size. Equivalent length-based criterion algorithm is proposed for a scheduled line single surface. Scanning path is planned within the given shape error, according to the way of equivalent length and different bending angles. Based on the algorithm requirement, the relationship between process parameters and bending angles is researched. During the experiments, bending angles are measured by a real-time monitoring system. The experimental results reveal that the laser bending angles are linearly proportional to the number of irradiations and laser line energy in a certain parameter range. Then, the experiments according to scanning paths verify the applicability of the proposed method.

Presently it is believed that the incident power is just the critical power of the nonlocal spatial solitons when the output beam width equals the input the beam width. The power decided by this method is generally not one and only, even is the power of breather. A theory is brought forward that one should find the critical power of the solitons on turning area of the curve of output beam width versus the input beam power. According to this theory, the experimental data obtained in lead glass are fitted, and the exact value of the soliton critical power is obtained.

Based on the nonlinear Schrdinger equation and the stepped Fourier method, the shape and spectrum evolutions of continuous-wave perturbed by an optical pulse with Gaussian-typed continuum spectrum in an optical fiber are numerically simulated. The results show that, due to modulation instability in the anomalous dispersion region of the optical fiber, this pulse perturbed continuous-wave can also evolve into high-repetition-rate pulse trains, which is similar to the case of sine perturbed one. Being different from the latter case, however, the generated pulses are not equal to each other in terms of widths, intensities, and intervals. When soliton parameters are too small or the optical wave is in the normal dispersion region, only attenuation oscillation structures instead of pulse trains can be generated. And the characteristics of pulse trains or oscillation structures will vary with the soliton parameters. These evolution characteristics are obviously different from those of conventional sine perturbed continuous-waves and Gaussian optical pulses.

It is an alternative means of changing the distribution of light beam at the focusing spot and realizing optical superresolution by a pupil filter. A new type of superresolving pupil filter based on Bessel function is introduced. Two-zone, three-zone and four-zone pupil filters are discussed in detail and the superresolving figures of merits such as normalized compression ratio, Strehlratio and maximum sidelobe energy ratio are analyzed respectively. The results show that this new type of pupil filter based on Bessel function has the ability of superresolution.

The manufacturing of large-scale diffraction gratings is always one of great tasks, and how to obtain meter-sized is also a very difficult problem. The appearance of the chirped-pulse amplification (CPA) promotes the need of gratings. Because of technological and financial limit, an alternative to mosaic two or more gratings into an equivalent single grating is proposed. Theoretical research of tiled-gratings is described, and experimental studies which include alignment errors test, accurate adjustment and stability control are also introduced.

The Fresnel zone plate (FZP) scanning imaging is an active unconventional imaging system, which uses two-dimensional (2D) optical scanning to achieve three-dimensional (3D) high resolution imaging. The basic principle, system structure and performances of several different types of FZP scanning imaging systems are demonstrated. The developmental status and application foreground are analyzed.

Subsurface damage (SSD) produced in traditional optical fabrication will reduce service performance and lifetime of optical elements. It is necessary to detect and control the subsurface damage in the fabrication process. Destructive and nondestructive detection methods of subsurface damage are analyzed. The merits and demerits of these detection methods are also discussed. The gap of subsurface damage detection technologies at home and abroad is presented, and the trend of subsurface damage detection technology is described.

In many application fields of narrow linewidth lasers, laser frequency stability is an extremely important parameter, and characterizes the degree of frequency stability. Based on the virtual difference between passive frequency stabilization and active frequency stabilization——having stable frequency reference standards or not, laser frequency stabilization techniques are studied, especially for active frequency stabilization: classification is done based on the selection of frequency standards; the theory and reason of reaching different precisions of frequency stabilization technologies commonly used are analyzed; advantages and disadvantages are compared based on reports of the active frequency stabilization at home and abroad. By comparison repeatedly, the PDH technology has obvious advantages, can obtain high frequency stability.

Optical communication is heading to high speed, broad bandwidth and large capacity, and it is more and more important to develop optical devices with superior performance and lower cost. Electroabsorption modulated laser (EML) is the ideal light source in long-reach and high speed optical communication at home and abroad because of its small size, tiny chirp, low driving voltage and high relaxation oscillation frequency. However, EML is very sensitive to temperature and the slight changes in temperature will affect the stability of operation. Therefore, it is a technical problem to keep the wavelength and output power stable and extend the life of the EML. Current research and development of cooled laser and the two main device packaging technologies are introduced and a prediction on small-form cooled EML in the future is made.

Based on the background of application of modern laser industrial manufacturing, the diagnostic technology of laser beam is discussed. Starting from the definition of laser beam width, two different kinds of laser beam width definition are compared. The relationship between laser beam diagnostic technology and definition of laser beam width is described. Then, according to the development of national and international standards, the beam width, beam divergence angle measurement and calculation are presented. Focusing on the principle and equipment based on the principle of hollow needle, the method with purpose on engineering application is discussed. The analysis results show that the definition including power (or energy) defined percentage of the total power beam width is better suitable for engineering application and the beam diagnostic technology based on hollow needle combined with hyperbolic fitting method, and it will well define the lasers performance capability.

Several sorts of laser jamming technology, most commonly used in the current war, and its current situation and the development trend are summarized firstly, then the performance and characteristics of laser jamming technology are introduced, and the function, jamming theory and key techniques of laser jamming of angle deception are discussed purposefully. Based on the above analysis, a kind of hardware-in-the-loop (HWIL) simulation evaluation method, which is the foundation to jamming effectiveness for laser jamming of angle deception equipment against laser guidance weapon, is proposed and the function, form and main problems existing in this system are analyzed. Finally, the development of test theory of laser jamming with angle deception equipment in shooting range is pointed out.

Progress of both theoretical and experimental results about self-similar soliton fibers laser are presented. It is pointed that the master equation is complex Ginzburg-Landau equation (CGLE) instead of nonlinear Schrdinger equation (NLSE) which expounds the dynamics of evolution of self-similar soliton pulse with gain fibers because of the gain dispersion. And there has a detailed discussion about the methods of evolution features of self-similar soliton pulse, mode locked and chirp compensation about the dispersion-management fiber lasers, dissipative solitons fiber lasers, light-dark solitons fiber lasers and vector solitons fiber lasers. It has also emphasized the principle of self-similar solitons fibers laser. The applications of self-similar solitons fibers laser and the problems to be solved in the research of that are pointed out.

The main methods of generation and amplification for tunable ultra-short middle-infrared laser pulses, based on nonlinear optical parametric process, are introduced briefly. The technical characteristics of the parametric oscillator, difference frequency generation, optical parametric amplification and chirped pulse optical parametric amplification are compared. Focusing on both expanding the gain bandwidth and improving the output power, the latest developments in the field of ultra-broadband optical parametric amplification and optical parametric chirped-pulse amplification in the past decade are highlighted. In addition, the key issues and technology bottlenecks as well as solutions of access to high energy/power and short pulse (broader bandwidth) are discussed.

Ultra-smooth surfaces are widely used in the field of optics, and the polishing method is an important component of super-precision technology. Firstly, the characteristics of ultra-smooth surfaces are introduced, and the classification and comparison of the polishing methods are made. It is shown that the non-contact method is the ideal ultra-smooth surface polishing technology. Then the existing ultra-smooth surface polishing technologies are summarized, and the machining mechanism, precision and application spectrum are expounded. At last, the gap of ultra-smooth surface polishing technologies at home and abroad is present, and the trend of the technology is described.

Studies on the high energy ion beams generated in ultra-intense laser-plasma interactions have made considerable progress recently due to the development of high power laser technologies, such as fast ignition of inertial confinement fusion, tabletop proton accelerators, and medical applications. Now the research of energetic proton is one of the hotspots. During ultra-intense laser-plasma interaction, the effect of plasma density scale length on accelerated hot electrons and high energy proton is great. Therefore, in order to know the hot electrons or high-energy proton acceleration mechanisms, it is necessary to determine the density of the plasma density scale length. We discuss the generation mechanisms, beam characteristics, diagnostics, potential applications and recent studies of high energy particles, especially protons, produced by irradiating solid targets with ultra-intense laser pulses.