We analysed two kinds of optical fiber ring resonator structure made of twisted fiber, and indicated that the two kinds of structure can keep Faraday rotation and can be used in current sensors and optic fiber gyros. The structures are also counteractive to temperature disturbance. Theoretical and experimental results are given.

Theory of three cladding dispersion compensating fiber with negative dispersion slope was analyzed, and the effects of all parameters on the fiber′s characteristics were given. We found that the dispersion compensating fiber with negative dispersion slope can be achieved only in limited range and at the cost of larger negative dispersion value. And spinning preform when drawing was adopted to lower the polarization mode dispersion in fiber. The advanced dispersion compensating fiber was made through modifying chemical vapor deposition (MCVD) method.

A new type computer generated hologram (CGH) is described. On the basis of two channel CGH, it can generate four independent images in four different directions by adding positive or negative quadratic phase factor on object spectrum, and has the character of self focusing. The experimental result is given.

Based on the mechanism of the water adsorption of the gelatin material and the experimental results concerning the degeneration of the gelatin holograms in damp environment, a water adsorbing and gelatin hologram degenerating model (WAGHDM) is proposed. The WAGHDM is used to give mechanism explanation for several experimental results about the degeneration of the gelatin holograms. The results show that it can give right explanation is valuable to the work of improving the environment stability of the gelatin hologram.

The diagnostics of 3 D arc temperature fields by the Talbot effect Moire technique and limited angle tomography algorithm has been studied on the basis of arc plasma physics.

The characteristic of Rowland circle concave gratings is analyzed with the scalar wave theory. The deviation of the image position from that predicted by the grating equation is calculated. This result can′t be obtained by the geometric ray tracing method. The calculated result of the dispersion and resolution consists with that calculated with the geometric ray tracing method. The image quality affected by the groove number, the mode size and the groove rounding is analyzed in details. The wave aberration and the ray aberration are also given.

Fabrications of chirped fiber gratings using spherical lenses and zero order nulled phase masks are studied theortically and experimentally in details. The results show that this method is suitable for producing fiber gratings with small chirp parameters, and will led to servere unsymmetrical reflection spectra and cladding mode coupling when the chirp parameters of the gratings are relatively large.

A new type of wavelength conversion technology is presented, which is based on a hybrid integrated DBR laser with a fiber Bragg grating as its external cavity. A conversion spacing of 8 nm was obtained. Measurement results of sensitivity on injected signal and the out of phase characteristics between input and output pulse signals are described. The mechnism of the wavelength conversion is discussed.

Based on the density matrix theory of quantum system, the spectra of optically pumped superradiant and cavity NH 3 FIR lasers and their optimum operating gas pressures are calculated by means of iteration method. The calculation shows that, compared with the optically pumped superradiant laser, the cavity laser behaves a wider band spectrum of FIR emission, a lower optimum operating gas pressure and a higher total output power under certain condition. Moreover, the cavity laser has characteristics of longitudinal tuning. The FIR laser emissions of the superradiant and cavity NH 3 lasers pumped by TEA CO 2 10R(8) and 9R(16) are measured experimentally, the results are in good agreement with the calculation.

The feasibility of a β-BaB 2O 4 single axial mode optical parametric oscillator is demonstrated by using a multi axial mode He Ne laser as seeder. The injection seeded OPO produce 2 mJ optical pulseat 632.8 nm with very narrow linewidth less than 600 MHz. The threshold for injection seeding was less than 1 mW.

We have compressed timing jitter of mode locked laser diode (MLLD) using 10 GHz base standard clock optical injection and 10 Gbit/s PRBS data pulse signal optical injection when the wavelength of the base standard injection clock light is equal to the wavelength of MLLD. Small timing jitter of 0.25 ps was obtained at -5 dBm injection optical power. The quality factor was 3000 with hybrid MLLD when the electrical power was +27 dBm.

The diode pumped intracavity SHG laser using a new type Nd: YVO 4 crystal is reported. We have compared the output characters of the new type with old type crystal Nd: YVO 4. The optical conversion efficiency of the new one is two times higher than that of the old one. The slope efficiencyis up to 31%. In addition, the output power of green light is up to 108 mW. The single longitudinal mode can be operated by decreasing the pumping power. The output power of single frequency green light is more than 10 mW.

The wavelength dependence of absorption of laser has been studied experimentally in the “Sheng Guang” and “Xing Guang” laser facility with the gold disks at a some chosen angle of incidence. The experiments show that inverse bremsstrahlung absorption is the main absorption mechanism and the the absorption increases when laser wavelength decreases. Although the absorption of 0.351 μm laser at 10° angle of incidence is higher than that of the others, the absorption of 0.351 μm laser at 45° angle of incidence is only 75% and scattered light is up to 25%.

The lattice mismatch between LiAlO 2 and GaN is only 1.4%, so LiAlO 2 is expected to be a promising substrate for the epitaxy of GaN. In present work, large sized and transparent LiAlO 2 single crystal has been grown by using temperature gradient technique. The crystal quality was characterized by the methods of chemical etching, optical microscope, TEM and synchrotron source X ray topography. The results showed that LiAlO 2 grew along 〈100〉 direction when it crystallized without using seed in Mo crucible. The crystal was free from bubbles and inclusions, and the dislocation density measured on (100) crystal plane was about (3.8￣6.0)×10 4 cm -2 . The main defects were subgrain boundaries, which may be caused by the fluctuation of temperature field in the furnace or over high growth rate. These two parameters should be optimized in further.

The analytical expression for the intensity and phase through two wave coupling in photorefractive crystal is deduced with a simple model. The effect of parameters on the two wave mixing was analyzed theoretically. The experimental data of two wave mixing in BaTiO 3 crystal are discussed.

The backscattering and saturation effects on the statistical properties of a bidirctional ring gas laser are studied theoretically. The effective eigenvalue of the intensity autocorrelation is calculated. Compared with experimental measurements, excellent agreement between the full saturation theory with backscattering and the experiments is obtained. Other laser theories lead to relatively large errors.

The effect of the polarization orientation of a linearly polarized optical wave on two photon absorption in GaAs semiconductor is analyzed theoretically. Optical limiting based on two photon absorption of different optical wave polarization orientations is performed in a GaAs sample, and the performance of optical limiting is improved.

A polarization independent optical switch of interference type on x cut LiNbO 3 with traveling wave electrode is proposed. The switch has a large bandwidth up to 6 GHz and a relatively small crosstalk less than 14 dB under the polarization independent switching voltage of 19 volts. Further improvement of the structure can make the crosstalk down to -20 dB.

Local poling structure was proposed for the application in polymeric electrooptic modulator. With this structure, full symmetric push pull operation can be realized in modulator. We suggest the use of microstrip line electrode instead of coplanar electrode and the use of soltline to ground electrode in microstrip line. The overlap integral between lightwave and microwave were calculated. Performances of devices with two kinds of electrodes were compared. Results show that the performance of the modulator with local poling structure will be enhanced considerably.

The effect of the condition of the coefficient matrix obtained from the simultaneous measurement of two parameters by fiber optic sensors on the error of the measurants is analyzed. A pre procession method to transform the matrix from the illconditioned to the well is proposed. The method is applied to the matrix in references and respectively, and the condition number in reference is reduced from 342 to 4, and in reference is reduced from 161 to 3.

A dual wavelength polarimetric sensor for the simultaneous measurement of strain and temperature was demonstrated using a bow tie fiber. In the measurement range of 500 μm and 70℃ the maximum errors are ±8 μm and ±2.5℃, respectvely. The sensor has a good stability because only orthogonally fundamental modes are used.

The avalanche injection model of nonlinear photoconductive semiconductor switch is presented. The effects of the voltage across the switch, deep level impurity density and optical pulse energy on the delay time of output pulse are discussed theoretically. Some important results are obtained.

A novel silicon micro mechanical sensor of all optical type is proposed. The theoretical analysis on structure and working principle of the sensor are presented, as well as the test and result of sample are expounded. The flow sensor has a structure of cantilever beam with ridge waveguide. The cantilever beam can be used as sensitive area of device and the probing optical beam may transmite in the ridge waveguide.

A smart Pseudo Schimidt system is introduced with a afocal corrective lens through which the ray bundles pass before and after the reflection of the primary mirror. The image quality of this system reached the diffraction limit with 2.7 m focal length, 3.42° field of view and F/5.5. The design idea and method are presented.

A generalized form of unified colored noise approximation is applied to obtain the Fokker Plank equation for intensity distributions of the dye laser colored cubic moldel. Analytic expression for the intensity distribution is derived. The experimental and simulation results of intensity fluctuation and the influence of colored pump noise on intensity fluctuation are described.

A series of Nd 0.9 Ca 0.1 Ba 2Cu 3O 6+x samples with different oxygen content were fabricated by the solid state reaction method and thermal treated under different conditions. Thephase structures of these samples have been verified with XRD method. The structural transition from tetragonal to orthorhombic phase appeares with increasing the oxygen content. Furthermore, the characteristics of structural phase transition were investigated with the infrared absorbance spectra methid. The variations of 642 cm -1 , 578 cm -1 , 538 cm -1 peaks are corresponding to the structure transition induced by the oxygen content. And the relation between the structure and the superconductivity has been discussed.

From the nuclear Schrdinger equation of a diatomic molecule with the vibration rotation interaction term involved in, under the Morse potential approximation, we derived the wavefunction relevant not only with vibrational quantum number, but also with rotational one. The Franck Condon factors of the α band system A 2Π→X 2Σ + and the γ band system C 2Π→X 2Σ + of BS molecule are calculated by using the derived wavefunction. In the calculation, the rotational quantum number J takes values from J=0 up to J=200. The results fit for low or high temperature condition and also the condition of strong shock wave.