The paper introduces a way that uses telescope for increasing the coupling efficiency of the fiber. It aims at that to those low coupling efficiency system, proper telescope can increase coupling efficiency greatly. To the laser TA 100, the telescope of 1.6:1 makes the coupling efficiency of single mode fiber reach to 70%, and which of polarization maintaining single mode fiber reach to 67%. The paper also introduces how the distance of two lenses affects the coupling efficiency in experiments, how to select the telescope, and the fiber couplings of other lasers.

An integrated optical polarization independent reflector on LiNbO 3 using Ti diffusion has been proposed according to the theory of two mode interference in this paper. Its principle has been analyzed. With the beam propagation method (BPM), the reflecting characteristic and adaptability with the wavelength change of the reflector have been accurately calculated. By optimizing its configuration parameters, the reflecting ratio is more than 20 dB (99%). Some actual samples have been fabricated and the measured reflecting ratios of both TE/TM mode have reached more than 18.5 dB in the experiment.

In this paper, a narrow linewidth single frequency distributed Bragg reflection (DBR) fiber laser was fabricated using Er:Yb codoped fiber. The laser was pumped by a semiconductor laser operated at 980nm and an output power of 2 3 mW with linewidth less than 5 MHz was obtained when pump power is 75 mW. Wavelength of the laser is 1557 524 nm. An active fiber sensor based on the DBR fiber laser was applied for temperature sensing and the experimental results show good linearity. This system has the merit of easier wavelength detection owning to its high signal to noise ratio and output power.

A simple optical field overlap method is reported to calculate the transfer coefficient of fiber ring resonator, the heart of the resonator fiber optic gyro. The results are applied to the investigation of influence of spectral linewidth of laser on resonance characteristics in fiber ring resonator. Furthermore, analysis has been made of relationship between the shot noise limited sensitivity of resonator fiber optic gyro and optical parameters in fiber ring resonator under some spectral linewidth of the laser conditions. The results are provided to theoretical basis for optimization design of resonator fiber optic gyro.

effect of the metal film was used to tune the FBGs by temperature. The method has advantages of simplicity, easy to use, small size, high tuning speed and easy to be integrated with circuits. When the applied current increased from 0 mA to 180 mA, the Bragg wavelength of the fiber grating increased from 1553.14 nm to 1555.48 nm with tuning range of 2.34 nm. The rise time of tuning was measured to be around 20 ms. Some experimental results are discussed in the paper.

A wide angle beam propagation method in an oblique coordinate system (OCS WA BPM) based on coordinate transformation is used to simulate optical waveguides. Compared with conventional wide angle BPM in rectangular coordinate system (RCS WA BPM), much better results are obtained with this method especially for waveguides with large tilted angle. This approach is also applied to Y junctions, and expected results are obtained.

A nonuniform photovoltaic field is created in Fe:LiNbO 3 during hologram recording exposures. Experimental results and analysis show the degradation of the volume holograms in the presence of the photovoltaic field. A sodium chloride solution is used to short circuit the crystal to improve the stored images quality. 1000 holograms which can be reconstructed with high fidelity have been stored in a common volume of the crystal which was placed in the sodium chloride solution.

In this paper, multiplication model of speckle image in imaging lidar is analyzed, and then suppression processing for the speckle image is finished by homomorphic wavelet filter. The experimental results show that this filter can suppress effectively the speckle noise and keep the image edge. Meanwhile, the experiment results prove that multiplication model is useful for speckle image.

The optical modeling of computational shadowgraph, schlieren and interferometry is discussed. The results of CFD (computational fluid dynamics) and transmission of optical waves through theoretical flowfield are used to generate digital pictures that simulate real observations. Concerning the specialty of the axis symmetric flow, the integral calculation in the equations of the optical model is simplified. A ring belt method is developed to obtain three dimensional integral results from two dimensional CFD results to process graphic rendering of computational flow imaging for axis symmetric flow. This technology provides a better insight into the flow physics and is extremely useful to experimentally validate CFD codes. An example for hypersonic blunted cone flow in ballistic range is illustrated.

With the development of multiplexing holographic storage in Fe:LiNbO 3, it′s absolutely necessary to modify or reedit the data stored in the crystal, so selective erasure is indispensable. In this paper, the principle of selective erasure and some methods for introducing π phase shift is reported, by recording the complementary hologram which leads to the complementary refractive index changes, the process of selective erasure can be realized. At the same time, some experiment results are also demonstrated and the analysis of these results are given.

Laser remelting of thin plate, made of 5Cr4Mo3SiMnVAl(012Al) die steel and Cr12MoV die steel with thickness of 0 3 mm to 0 8 mm, was carried out by the use of pulsed Nd:YAG laser. The effects of technical parameters such as pulsed width and pulsed frequency, materials and materials thickness on the deformation characteristics of thin plate were studied. The results show that the deformation of thin plate die steel during pulsed Nd:YAG laser remelting is quite serious and the value is the same as the amount of materials thickness, and the maximum deformation value of thin plate in the thickness direction increases with the increase of pulsed width or the decrease of pulsed frequency or the decrease of materials thickness, and the maximum deformation value of thin plate in the thickness direction of Cr12MoV die steel is bigger than that of 012Al die steel. The main reasons are the differences of laser remelting technical parameters, the dissipated heat case of materials and the thermophysical properties of materials and the thermophysical properties of materials.

Based on the experiment, the process of doping of Zn into InP induced by pulsed laser was analysed, and the temperature distribution analytical expression across the finite double layer Zn/InP irradiated by pulsed laser is presented.

A large area of Co based alloy coatings on alloy struction steel 20CrMo has been successfully obtained by using a 6 kW CO 2 laser and synchronous powder feeding system. By means of metalloscopy and X ray diffraction, the microstructure of the coating is investigated. The microhardness, bending strength and corrosion resistance are measured. The experimental results show that the cladding layer is of fine dendritic microstructure, the phases of coating are composed of Co based solid solution,CrB,M 23 C 6 et al.. Compared with cemented carbide hot roller presently, the cladding layer has a little higher microhardness, equivalent bending strength and improved corrosion resistance.

In this paper, the melting solidifying characteristic of Ni based metallic powders by selective laser sintering was studied. It was found that the molten pool shape affected solidification features of the sintering forming materials. The experimental results show that the sintered materials were multi layer structure, and the morphology of the microstructure and the compositions in a layer were not uniformly distributed. The basic mechanisms of the sintering prepared materials were discussed.

A LD pumped, Cr:YAG passively Q switched Nd:YAG/LBO blue laser was reported. With 1600 mW incident pump laser, Q switched blue laser with average power of 9.1 mW, pulse duration of 14.5 ns, repetition rate of 4.19 kHz and peak power of nearly 150 W were obtained.

A high power continuous wave 1.34 μm Nd:GdVO 4 laser end pumped by laser diode array with plano concave resonator was reported. At the incident pump power of 14.75 W, the maximum output power of 4.62 W was obtained with the corresponding optical conversion efficiency of 31.3% and the average slope efficiency of 32.9%. By using the experimentally measured threshold data and slope efficiency, the stimulated emission cross section of Nd:GdVO 4 crystal was determined to be 1.95×10 -19 cm 2.

Materials of InGaAs/AlGaAs separate confinement heterostructure strained single quantum well were grown by the technology of metal organic chemical vapor deposition (MOCVD). The 1 D semiconductor laser linear arrays were made using this materials,then they were assembled to form 2 D array. It′s peak wavelength is 903 nm, the full width at half maximum (FWHM) is 4 4 nm, the peak output power is 730 W (pulse width 1000 μs, drive current 77 A), and the density of output power is 487 W/cm 2. The laser can work very reliably over 8600 hours in this condition.

The color center absorption properties of as grown and H 2 annealing Yb:YAG with different Yb 3+ doped concentration have been studied,and its concentration is not consistent with doping concentration of Yb 2O 3. The fluorescence spectra and fluorescence lifetime of Yb:YAG are measured. It is only when the doped concentration more than 10at. % that the color center has a evident quenching effect on fluorescence intensity and fluorescence lifetime of Yb:YAG.

In this paper, a method was reported that used a high precision optical spectrum analyzer to measure transmission resonant frequency of air gap F-P etalon and got its free spectrum range by linear fitting. The spacing of F-P etalon was calculated based on this. The measuring precision of this method was analyzed, which showed that the relative error of F P etalon spacing measurement was 2×10 -3 . A novel method of F-P etalon perpendicularity adjusting was introduced as well.

In this paper, a new difference Laser Doppler Vibrometer with directional discrimination is introduced.Two phase detecting technique used to distinguish the direction and the intensity distribution of the phase grating diffraction pattern is analyzed. The phase grating is a frequency mixing device that can get high SNR signals. The experiments prove that the system can be used to measure torsional vibration and distinguish the rotating direction of the rotor, which can arrive at a high accuracy.

According to “black box” theory, the measurement system of turbid media 180° back scattering characteristic was designed. Using the system, the back scattering characteristic parameters for different mixtures with different concentration milk and de ionized water were determined. As a result, the relationship between concentration and scattering characteristic was deduced.

A kind of polymer poly(disilanylene 2,2′ bipyridine 5,5′ diyl)ruthenium (PDSBpy Ru) with a σ π alternating conjugated backbone was synthesized. The photorefractive effects were investigated by two beam coupling (2BC), degenerated four wave mixing (DFWM) and field induced orientation birefringence at 532 nm. This polymer shows an enhanced photoinduced metal to ligand charge transfer (MLCT) inside the ruthenium complex. The coupling coefficient and the diffraction efficiency are measured to be about 30 cm -1 and 10%, respectively.

This paper illustratively analyzes the nonlinear evolution of phonon wave density grate in a stimulated Brillouin scattering (SBS) process by using the principle of light forces, and discusses the characteristic difference between steady state narrow band SBS and steady state broad band SBS.