The ability of the retroreflector array to provide psedophase conjugate wave of the input wave is investigated and the calculated results of different Zernike polynomials aberrations are presented. The matching problems about the number and position of microlens array between retroreflector array and Hartman-Shack wavefront sensor in common path/common mode adaptive optical system are analysed. The errors of mismatching are given.

Pulse width can be conserved when picosecond solitons propagate through a decreasing dispersion fiber of which the group dispersion exponentially decreases along the fiber length at the same rate as the energy loss. However, for keeping local balance of the dispersion and the self phase modulation, the group dispersion of the decreasing dispersion fiber in which sub picosecond solitons propagate should be modified as a result of the combined action of Raman self frequency shift and the third order dispersion. The group dispersion of the decreasing dispersion fiber has been adjusted and the propagation of sub picosecond solitons through a decreasing dispersion fiber has been investigated by solving numerically the generalized nonlinear Schrdinger equation. The results of the numerical simulation are consistent with theory.

The numerical method to calculate fundamental modes of W Tunneling optical fibers is given. By using field ditribution of the fundamental modes, the tunneling process, strength and direction are analysed. It is found that the tunneling effects increase remarkably when the fundamental modes are cutoff, and they are concentrated mainly in the direction of the semiminor axis of the elliptical inner cladding.

A simple analytical optical power transfer function is derived in frequency domain for intensity modulation systems with fiber loss, chromatic dispersion and self-phase modulation. Expression to calculate the distortion of arbitrary optical power waveform is obtained with distinct physical meaning of each term. The results show that the induced power variation is proportional to the square of modulation frequency (SOMF) at low frequency region, while proportional to the sine of SOMF at high frequency region. The analytical result agrees well with numerical simulation under weak modulation and can correctly predict the time-domain waveform under strong modulation such as non-return-to-zero in intensity modulation/direct detection systems.

Based on the eigenvalue equation equation of waveguide for scalar quantity and the recursion relation of its eigen-functions, a kind of theoretical method, by which waveguide dispersion in single mode fiber can be analytically solved by means of the equation called D. Gloge model, is put forward and the analytic solution of the dispersion in single mode fiber is given out. It shows that the analytic method can almost precisely solve dispersion problem of single mode fiber by analysis of a difference between approximate and accurate solution of the normalized transmission constant. Experimental data and calculated curve of the dispersion about general single mode fiber (G.652) is compared and they dovetail very well. By use of the result, the calculating precision of numeric differential method and empirical formula is analyzed.

The self induced phase matching in four wave mixing in a nonbirefringent single mode optical fiber has been observed. It has been shown that in a nonbirefringent single mode fiber the phase matching necessary for four wave mixing can be accomplished with the combination of self phase modulation and cross phase mdulation induced by pump laser pulse.

A new linear sensing method of deflection and stress, in which the fiber grating bandwidth is stretched by using bilateral cantilever beam, is reported. The theoretical studies and the experimental results show that the bandwidth of fiber grating is sensitive and linear to deflection and lateral force. In the experiments, the range of linear sensing is not less than 17 nm. The sensing sensitivities are 0.658 nm/mm and 5.32 nm/N, respectively.

Controlled by an 1×3 optical switch, light from a pulsed broadband source was launched into one of 3 independent strings of 5 FBG sensors. By introducing suitable length of fiber as time delay between adjacent two gratings in the same string, the return signals can be selected by a programmable electric switch. Demodulation was achieved by using an unbalance Michelson scanning interferometer. Combined spatial and time division multiplexing operation was demonstrated successfully.

A novel hierarchical image fusion scheme based on contrast pyramid decomposition is presented. The basic idea is that: first to perform a contrast pyramid decomposition of each source image, and then the contrast pyramid of the fused image is constructed by using region based weighted operators according to different fusion rules, finally the fused image is obtained by taking inverse pyramid transform. This approach has been successfully used in image fusion. In addition, with the use of the parameters such as entropy, cross entropy, mutual information, root mean square error and peak to peak signal to noise ratio, the performance of the fusion scheme is evaluated and analyzed. The experimental results show that the fusion scheme is effective.

A new method is presented to enhance the image edge using photorefractive two wave coupling. In the setup for real time writing and reading, the Fourier transform hologram using Cr:SBN crystal as the recording medium, the spatially separated high and low frequency components of the object beam will couple with the reference beam individually. The coupling results in the enhancement of the relatively weak high frequency component, because the intensity of the high frequency carrying the edge information of the object is much weaker than that of the low frequency. It discussed that the influences of the crystal axis orientation and the intensity ratio of the reference beam to object beam on the image edge enhancement. The physical mechanism of the image edge enhancement under different reference object ratio is analyzed. This Cr:SBN crystal can be used as a model of optical dynamic filtering for image edge enhancement.

An optical system based on polarization and area coded scheme and the multiple imaging technique is proposed for fuzzy image processing. In this scheme, each encoding cell is only composed of one encoding cell so that the resultant pattern is still the image in which there is no space between any two pixel rows. All of the fuzzy logical functions of two images can be implemented in parallel and spatial invariant by programming the lens arrays with corresponding modes. In particular, no thresholding device and decoding mask are needed, therefore, the system exhibits a high operation speed and a large information throughout. The experimental results are given.

The principle and design method of employing the thermal property of diffractive optical element to athermalize optical systems are expounded. A method utilizing the best image plane to determine the optimum correction coefficient in order to optimize the performance of optical systems in required temperature range is described. The optical prescription and evaluation of an athermalized and achromatized IR system in temperature range 20 ℃～50 ℃ and 8 μm～12 μm waveband are given. The system has simple construction and reliable performance in required temperature range.

A photothermal modulation laser diode interferometer that is insensitive to external disturbances such as fluctuations in the wavelength of the laser diode and mechanical vibrations of the optical components is proposed. A feedback control system is designed to control the wavelength of the light source and reduce the phase measurement errors of interference signal. The measured results show the usefulness of the interferometer.

An improved algorithm of beacon light phase reconstructed is developed with the data of slope and data of intensity of subaperture measured by Hartmann sensor. This measured data of phase gradient is analyzed based on the improved algorithm. The result showes that there is branch points in beacon light phase in strong scintillation for the measured phase gradient.

Based on the principle of passive mode locked laser and combining the characteristics of the equivalent fast saturable absorber in self mode locked solid state laser, the self mode locked dynamic equation and rate equations for controlling the running states are discussed. The condition of self Q switched self mode locking is obtained and the relation between the period of self Q switching and structure, running parameters of solid state lasers is presented. The agreement of the theoretical and experimental results is good enough.

Transient characteristics of fiber Bragg grating external cavity laser are presented. An effective photon lifetime is introduced to describe the photon behavior in external cavity condition. Simulation results show that the length of external cavity should be shorter than 4 cm in order to ensure the modulation frequency to be larger than 2.5 GHz. Single mode emission of an external cavity laser was obtained experimentally at 1 GHz modulation with side mode suppression ratio better than 40 dB, 3 dB dynamic line width about 0.1 nm, and 20 dB dynamic line width about 0.3 nm.

Absorption spectra, emission spectra induced by 346 nm, 363 nm (1D2), 475 nm(1G4), 698 nm (3F2, 3F3) and 801 nm (3H4) light, and excitation spectra of fluorescence spectral lines at wavelengths of 454 nm (1D2→3F4), 475 nm (1G4→3H6), 646 nm (1G4→3F4), 806 nm (3H4→3H6) of trivalent Tm3+ ion in YVO4 crystal were measured. Transition processes of the energy levels of Tm3+ are analyzed in details. The idea of energy transfer and new transition channels between Tm:YVO4 host and energy level of Tm3+ ions were proposed. It is confirmed that there are energy transfer processes including 1D2+3H6→1G4+3F4 and 1G4+3H6→3H4+3H5, cross relaxation process 1G4+3H6→3F2+3F4 may be present yet. These energy transfers make the upconversion 1D2→3H6 (454 nm) difficult while the upconversion luminescence of 475 nm (1G4→3H6H) is strong and 3F0 is the potential infrared laser emission energy level.

KDP crystals with different concentrations of H 3BO 3 in solution were grown. Light scatter was detected with ultramicroscopic method. It has been proven that light scattering in KDP crystal aggravates with the increasing concentration of H 3BO 3 in the growth solution. The light loss and the transmittance characteristics were measured in KDP crystals. The experimental results show that the characteristics of light uniformity and wave plate effect greatly depend on the concentrations of H 3BO 3 in solution.

The orientation of the azo dye molecules in polymer film induced by all optical poling is investigated and modeled. According to this model, when both writing beams with frequencies of ω and 2ω are linearly polarized with polarization direction parallel to each other, the majority of molecules in the films axially align in the direction perpendicular to the polarization of the writing beams, while the minority of molecules polarly align in the parallel direction, but only the latter contributes to the macroscopic second order nonlinearity in the polymer film. The model has been experimentally confirmed.

The problem of filamentation of optical beam in high power laser is studied by taking into account the effect of saturating gain. A set of propagation equations for small scale modulation is derived. An exact analytic solution to the derived equation is obtained in the case of small signal gain. In the case of saturating gain, the obtained equation is solved numerically. It is found that for a given input power, the cutoff spatial frequency, the fastest growing frequency and the maximum growth rate increase in an amplifying medium, and varied with propagation distance. The saturating effect of gain lowers the growth rate of the B integral and the small scale modulation propagating in the amplifying medium.

A simulation of dynamic nonlinear characteristics of high voltage optically controlled photoconductive semiconductor switches (PCSS′s) is performed with 2 D simulator MEDICI, and the emphasis is put on the mechanism of lock on and time delay under high electric field condition. It is found that the deep energy levels play an important role in lock on and time delay. They can dynamically change the distribution of electric field, carriers and current densities in PCSS′s, cause output current to delay and also strengthen the local electric field enough to cause avalanche. The simulated results agree with experimental results. It is concluded that the observed nonlinear characteristics are closely related to the introduced deep energy levels in PCSS′s.

The characteristics of the potassium Faraday anomalous dispersion optical filter (FADOF) at D 2 line were studied theoretically and experimentally, and the FADOF′s operating ways in line center and line wing were obtained under the different working conditions. The effect of temperature on the feature of the FADOF was discussed.

A 13 cm long linearly chirped fiber Bragg grating is achieved by precisely translating the photosensitive fiber and linearly chirped phase mask assembly as the ultraviolet writing beam is scanning. Reflectivity of up to 90%, bandwidth over 0.8 nm and dispersion as high as -1700 ps/nm have been measured. It is sufficient to compensate the dispersion over 100 km standard single mode fiber of 10 Gb/s optical pulses at 1547.74 nm.

The optimized Gires Tournois mirrors used for a femtosecond mode locked Ti:sapphire laser is reported. The electric field distribution as a function of wavelength inside the optimized Gires Tournois mirrors is calculated. The penetration depths in these mirrors change with wavelength. The penetration depth increases within the wavelength range from 720 nm to 9000 nm. So they can give larger time delay at longer wavelength range. They can be used as intracavity dispersion compensation devices instead of traditional prism pairs. With these mirrors and a semiconductor saturable absorber mirror, self starting 56 fs pulses was obtained in a mode locked Ti:sapphire laser.

Within the frame of the Schroedinger formulation of light beam propagation, the ABCD law is extended to the so called effective ABCD system which effective beam quality factor is conservative. The evolution equations of beam width, curvature radius and effective divergence are derived, respectively. For the effective ABCD systems which second derivative of beam width square with respect to the axial coordinate is a constant, the nonlinear evolution equations of spatial coordinate operator and momentum operator are obtained by means of Heisenberg picture, respectively, and the corresponding Huygens integral is solved by a simple iteration method.

Theoretical expressions of the radiation pressure for a dielectric sphere in the Rayleigh regime of light scattering under illumination of axial superposition of two Gaussian beams with different waist positions are derived. The results show that the standing wave trap produced by axial coherent superposition of non paraxial Gaussian beams is better than that of paraxial Guassian beams. On the other hand, the non paraxial standing wave trap produces stronger radiation forces than single beam trap. Moreover, the depth of potential well is four times deeper than that of single beam trap.

The cavity field spectra for the Jaynes-Cummings model with an additional Kerr-like medium are investigated. It is found that the two peak structure appears when the field state in pure number state initially. The peak space is 2χ and the "center frequency" of the spectrum is far away from the resonance frequency due to the increase of the field intensities. The cavity field spectra will be multi peak structure and the peak number increases quickly with the field intensities when the initial field is in superpositions of number states. The influences of the Kerr effect to the cavity field spectra become marked with the increases of the field intensities.

The effect of plasma density scale length on the conversion efficiency of high order harmonic generation in the interaction of intense laser and plasma was investigated via PIC (particle in cell) simulation. The conversion efficiency of high order harmonic generation produced by the interaction between p polarized, non relativistic laser pulse and over dense plasma with different density scale lengths was calculated. The plasma density scale length significantly affects the conversion efficiency and this effect is different for different harmonic order, different laser pulse duration and different plasma density.

A novel cascaded fiber Raman laser operating at 3rd Stokes 1240 nm using fiber loop mirror is reported. The output power at 1240 nm is 300 mW and convert efficient is about 25%, however, the properties of fiber mirror and the parameters of Raman fiber are not optimized.