In wavelength-division multiplexing (WDM) optical fiber communication systems, the signal quality after transmission can be severely impaired by self-phase modulation (SPM), cross-phase modulation (XPM) and four wave mixing (FWM) effects. A simple formula to estimate FWM effect is derived. Furthermore, during the nonlinearity simulation in WDM systems by single-channel method, a step-size formula is proposed to optimize between computing accuracy and speed. An alternative simulation method for GVD, SPM, XPM and FWM based on multiple-channel coupled-wave equations is also developed, resulting in significant decrease in computation workload.

There are N+1 gradient-index-rod lenses (GRINs) in a 1×N wavelength division multi/demultiplexer, forming a 1-to-N collimating system. Excess coupling losses arise due to the varying separations between the GRINs. The lengths of the GRINs need to be properly chosen to achieve a lowest average coupling loss. Numerical results show that the input GRIN is ΔZ0 longer than quarter pitch with ΔZ0=20～50 μm, depending on N. There is an upper limit for ΔZ0. The lengths of N output GRINs are differently shorter (ΔZi0) than quarter pitch. ΔZi increases from negative to positive starting from the near end to the far end GRINs, also depending upon N. The optimized matching GRINs assure the lowest coupling loss at N≤8, especially negligible at N≤6.

In accordance with the multilayer approach for analyzing graded-index waveguide, the WKB method is improved by correction of the phase shift term. Formulas for the improved WKB method and for calculation of phase shift are derived. Numerical results for typical refractive-index profiles (exponential, Gaussian, erfc, truncated linear) demonstrate that the present method is highly accurate up to near cut-off region.

A real-time and in-situ recording-fixing method after heating with CO2 laser beams is suggested to thermally fix a small local hologram in a bulk of Fe:LiNbO3 photorefractive crystal. With an insulator mantling the crystal, when two cw CO2 laser beams heat it to form a 200℃volume with the shape of Gauss beam, CO2 laser beams are blocked and Ar+ laser beams are used to record a photorefrative hologram, finally fixed a hologram in crystal before the temperature descended to 100℃. A heat transfer model and numeric solution are given. On the basis of simulation, a series of experimental result are obtained. Both experiment and theory analysis show that this scheme can fix a better hologram in real time and in situ, the temperature distribution is uniform.

The In:Fe:LiNbO3 crystal has been grown by doping In2O3 and Fe2O3 into LiNbO3. The measurement results show that, the In:Fe:LiNbO3 crystal has high light scattering resistance, high response speed and long storage conservative time. The mechanism of this crystal behaving holographic storage properties is discussed. The maximum value of the diffraction efficiency measured is 73%.

A neural network-based approach is proposed for invariant recognition of two-dimensional objects. The industrial tools to be recognized have one degree of freedom, the dynamic range of their shapes leads the feature vector not uniquely defined even for a single object. The Fourier descriptors of objects boundary are taken as the features being invariant to translation, rotation and scale changes. A multilayer feedforward neural net with two hidden layer classifiers is utilized. The experimental studies involving four sorts of mechanical tools are carried out. The performance is compared to a nearest neighbor rule. It is shown that the approach is robust to not only noisy but also varying feature vector, and the neural network can recognize some untrained objects.

A kind of reversal shear interferometer has been designed to measure the temporal change of spatial coherence of KrF excimer laser with an unstable resonator. By this method, we can get the spatial coherence degree from a single measurement. At different shear distance, using slit and photodetector. The stepwise increase of the spatial coherence degree at intervals equal to the transit time of the resonator was observed. Moreover, the ray matrix has been used to analyze the propagation of partial coherent light and the coherence widths of successive passes are calculated.

A technique of making 2D rainbow master holograms for embossing using non-coherent light source is described.In master hologram recording process, an uv-lamp is used as the light source, and no optical elements and anti-vibration devices are required. The color encoding is realized by fringe replication from the “rainbow plates”, in which the slit images are recorded.The “rainbow plates” can be used for many times, so the recording process of master holograms is very simple. The technique has the advantages of low investment, high production efficiency and good hologram quality. Therefore it is valuable for hologram mass production.

Laser conditioning is a new technology to enhance laser damage threshold of the optical coatings. The method of the small laser spot scanning and raising of energy step by step is applied to condiation several various multi-layer reflective coatings. It is found experimentally that the damage thresholds of the reflection coatings, except of HfO2/MgF2 multi-layer coating, such as zero-probability damage threshold F0%, minimum damage energy density FDmin, maximum not damage energy density FNDmax and 50% probability damage threshold F50% are all enhanced. It means that laser conditioning technology not only can eliminate the impurities and defects in the coating, but also can improve the whole properties of the coating.

Attenuated phase shifting mask (PSM) and that with optical proximity correction are adopted to improve resolution of photolithography based on some calculation results. And a new method of making attenuated PSM by encoding is proposed, and the theoretical calculation results are accordant to that of the conventional attenuated mask.

A novel soft X-ray spectrograph comprised of a toroidal mirror image optics, a high-density transmission grating and a soft X-ray CCD camera has been developed. The detecting range is in the wavelength region from 0.5 nm to 15 nm with a resolution of about 0.05 nm. The spectrograph has no astigmatism. A point object is imaged to a point. Owing to its high efficiency, even an X-ray spectrum of low-energy laser produced plasma can be measured. It is especially suitable for experiments of ultrashort femtosecond pulse laser produced plasmas.

The influence of vertical resolution and signal-noise-ratio (SNR) of confocal scanning microscopy (CSM) on three-dimention (3D) imaging ability is analyzed. The criterion for vertical resolution of CSM is given. A polarized CSM is designed to improve the SNR so as to obtain the microstructure of weak scattering object or strong surface reflection object or polarized object.

Based on the coupled matrix-density equations and Maxwell equations and considered the transverse effect of the laser pulses, resonant propagation of two laser pulses in three-level ladder system was presented under the cylindrical symmetry. The evolutions of pulses propagating in thick absorbers were studied. The spontaneous relaxation of upper levels is considered in numerical solutions. The calculation results show the evolution of pulse energy and the distribution of ionization particle.

The ionization rates of atom and atomic ions in an intense optical field are summarized systematically with the quasi-static approximation, on the basis of tunneling ionization theory in the static electric field. The error in the formula (13a) of reference [10] was modified. The ionization rates and threshold intensities of Xe atom and ions in both intense circularly polarized and linearly polarized field are computed and compared.

The thermal process is an important process of interaction between laser and optical coating. The “alternate recessive algorithm” was applied to solve the equation of the heat transfers in multilayer optical coating. The two-dimension thermal field in coatings was obtained. Some examples to calculate the temperature field in typical optical coatings were shown.

Considering the transformation from stored energy of electric capacitors to that of the laser medium, and introducing the temporal factor and three-dimensional spatial amplified spontaneous emission (ASE), numerical calculations have been performed to simulate the characteristics of the multi-segment amplifier (MSA), including temporal changes in the pumping balance between central and side flashlamp arrays, stored energy, gain coefficient and gain distribution of the MSA. The present numerical codes have been verified with the experimental data of LLNL, demonstrating the ability of the predicted performance for the MSA.

Numerical method is used to study dynamic characteristics of dual-wavelength femtosecond lasers and finite difference is used to solve cross mode-locking equations. The results show that two trains of mode-locking pulses interact in two-beam laser cavity and under specific condition, i.e., group velocity dispersion, self-phase modulation, cross coupling, gain amplification and loss are balanced, laser can be cross mode-locked, so cross mode-locking femtosecond pulses can be generated.

According to the charecteristics of the backscattered light from the rough surfaces of the target far away and the random phase matching rule, the method of coherent optical head coefficients designing is discussed. An optical system is developed that is an optical head of a coherent imaging CO2 laser radar with chirp pulse compression. In the experimental laser radar only one continuous wave single mode CO2 laser is used, and the signals from a building of 7.8 km away are obtained with acceptable SNR while the lase output is about 5 W.

Strained InGaAs/AlGaAs double quantum well lasers with two pairs of graded index (GRIN) heterostructure have been fabricated by MOCVD method. Its wavelength ranges from 970 to 982 nm, threshold current density is 140 A/cm2 at room temperature CW operation. 520 mW/facet and 1.49 W/facet for CW output optical power has been obtained under 0.9 A and 2.0 A operation, respectively. The maximum CW output optical power can come up to 2.4 W/facet.

Making use of optical phase conjugation effect and Q-switch effect in stimulated Brillioun scattering (SBS), a Nd:YAG laser with phase-conjugate resonator is developed. By this way, the reflecting mirror and Q-switch in traditional lasers are not used. The laser output is 100 mJ, and the pulse width is 13 ns. The corresponding total converse efficiency of the laser is 0.47%. In addition, a KTP optical parametric oscillator was inserted into the phase-conjugate resonator, the optical parameter oscillator (OPO) output wavelength of 1.57μm and the output energy of 15mJ can been obtained. The result indicates that the OPO in SBS phase conjugation resonator is feasible.

The principal refractive indices and the thermal refractive index coefficients of 0.075 mol fraction Nb:KTiOPO4 crystal have been measured by the autocollimation method at wavelengths of 0.5398, 0.6328, 1.0795 and 1.3414 μm. The sellmeier′s equations were obtained and used to calculate the type II optimum phase matching angle, the calculated results agree well with the experimental results.

The photoluminescence (PL) spectra and photoluminescence excitation (PLE) spectra under near infrared (800 nm) excitation from porous silicon (PS) prepared by electrochemical anodization method are measured. The results show that PS has efficient infrared-upconversion luminescence, and the peak intensity increased obviously as the reserved time prolonged. This nonlinear optical response enhancement effect is related to the excited local binded exciton interacted by space quantum confined effect. The multipeak in PL spectra show that there are many kinds of different luminescence centers.

A 1×4 multimode interference (MMI) optical power splitter is designed by means of guided-model propagation analysis. Considering the possible factors which would influence the properties of the device in the procedure of designing and fabricating, the influence of the parameters was analyzed, such as the width, the length and the index of waveguide, on the performance of the device. Then the MMI optical power splitter is fabricated and measured. The measuring results show that the fuction of the fabricated device can be realized. In accordance with the problems occured during the experiment and measurement, opinions and methods are presented to improve the performance of the device.

The performance of a polarization-independent isolator using a new type polarizing splitting prism are analysed in theory and studied by experiment. Theoretical and experimental results indicate that the isolation is nearly two times greater than before, and the insertion loss just increases a little. Experiment shows that the insertion loss and the isolation from fiber to fiber of the isolator are -0.82 dB and -48.1 dB, respectively.

The problem of atomic decay in the microcavity is discussed. Suppose that there are two atoms in the microcavity, the decay in the interaction between cavity wall and the dressed atom caused by strong couple of the two atoms and cavity field is discussed in specific initial condition. It is pointed out that the decay in that case is stronger when there are more photons in the microcavity.

The techniques of fabricating low loss optical organic polymer waveguides are demonstrated. A new methodCCD camera photographing methodis applied to detect the propagation loss in the waveguide. The samples with propagation losses less than 0.5 dB/cm at 632.8 nm are fabricated experimently.

Transparent glass-ceramics doped by Cr3+ was prepared by the process of phase separation and the raw materials of analytical reagents in the system of B2O3-Al2O3-SiO2. The absorption and emission spectra of glass and glass-ceramics were measured respectively. The spectroscopic characteristics were studied.

A simple and practicable method was adopted to image the biological samples, plant leaf epidermal cells after being fixed, using soft X-rays in a vacuum environment. The micrographs of their cells were acquired in the experiment. Compared with the image method in air, this method has some advantages such as exposure time decreasing and operation safe.

According to the chromatic′s theory, color sensitive functions of object, light source and human eyes are defined in the widely used CIE1976L*a*b* color space and color difference［1］. Mathematics formulae are deduced. The three kinds of color sensitive functions are studied systematically and comprehensively in the whole color space. The general law of color sensitive functions are concluded. Mathematics models of the three kinds of color sensitive function can be used in some fields such as computer color matching, making light source and simulation of human eyes of colorimeter.