From the analysis on wavefront aberration caused by high-speed airflow, it was found that aero-optics inhomogeneity is consisted of large-scale ordered and small-scale random inhomogeneity. With wavefront sensor, the large-scale aberration can be reconstructed. For the small-scale aberration, the coherent index is a better standard for measurement. However, the Lateral Shear Interferometer (LSI) can realize the two kinds of measurements. Therefore, the inhomogeneity of Free Vortex Dynamic Window (FVDW) was investigated by LSI, the one dimension wavefront aberration in output window was reconstructed and the random inhomogeneous scale distribution was given. Also, the main cause of inhomogeneity was discussed.

A diagnostic method for measuring plasma poloidal magnetic field has been reported. By using of HCN laser an interferometer/polarimeter has been designed and built. The Faraday rotation angle was obtained with the precision of 0.3°. Experiment result shows that the system can be used for measuring plasma poloidal magnetic field in HL-1M Tokamak.

The dual overwritten fiber Bragg gratings have been found the significant applications in telecommunications and fiber sensors. In this paper, the nonlinear perturbation to the refractive index induced by dual overwritten fiber Bragg grating is analyzed, and the spectral characteristics that can be achieved in dual overwritten fiber gratings with nonlinear modulation of refractive index are investigated by numerical simulation based on the coupled-mode theory. It is found that multi-wavelength reflection and strong second harmonics will occur in dual written fiber Bragg gratings when the nonlinear index perturbation becomes strong, which is very useful for multichannel wavelength-division-multiplexing. The method described in this paper is conducive to the fabrication and applications of dual overwritten fiber Bragg gratings.

By using the point-match method, the microwave effective refractive index is calculated. The concept of microwave refractive index of device is proposed. Using this theory, 100 GHz modulation bandwidth can be achieved when optical and electric signals match each other.

This paper introduces a new kind of compensator: three-in-one composite compensator. By comparing with the usual compensator, operating is convenient and the limit of adjustment is extensive.

Nd:YAG laser pumped dye laser was used to excite the OH radicals in flame of solid propellant at the transition V″=0→V′=1. The fluorescence at transition V′=0→V″=0 was collected by CCD detected system, and the two-dimensional images of the concentration of OH radicals in flame of solid propellant were obtained.

An electro-optical modulator was introduced to modulate the continuous light wave into pulses. An unbalance Michelson scanning interferometer was employed to transform the wavelength-shift signal reflected by the Bragg gratings to phase-shift signal. Signal coming from each sensor element was selected by controlling the on-off state of an electrical switch with a programmable delay signal generator and, therefore interrogation for time-domain addressing was achieved. Filtered with a band-pass filter, the measured strain can be judged by monitoring the phase-shift with a phase meter. Experiment demonstrated that the sensitivity of the 4-element sensor system, which was with a resolution of 6 nε, was 1.63 Deg/με.

According to the theory of light diffraction and the moiré image-encoding, a new technology of image-encoding using non-key phase-only moiré method is presented in this paper. The unique reconstruction nature of the non-key moiré encoded phase-only plate manufactured with this method can not be imitated with other technologies. If it is used in the anti-counterfeit domain, the technology can dramatically enhance the anti-counterfeit capacity of produces.

Surface on 2Cr13 stainless steel was cladded with Co-based alloy using a high power carbon dioxide laser. The microstructure and the constituent phases and corrosion resistance of the clad layer were investigated. The results show that if laser treating parameters were appropriate, the microstructure of clad layer would be very fine and its corrosion resistance is the best. The corrosion resistance was also improved as reflected by a reduction in the current density of least one order of magnitude as compared with the as-received 2Cr13 stainless steel specimen at the same potential. The improvement in corrosion resistance is due to the increase in Co and Cr content in the cladded layer. Under the condition of high temperature PbSO 4 salt corrosion, high Co content promoted the formation of fine CoO, CoO·Cr 2O 3.The fine dendritic structure and the Co-based alloy oxides help to retard the penetration rate of the sulphur ion which induces the intergranular corrosion.

In this paper, the gain characters of the new N 31 phosphate Nd:glass which made in China and the phosphate Nd:glass made in Russia are measured with a 2×1×3 multi-segment-amplifiers. And it is shown that the gain coefficient of N 31 phosphate Nd:glass is 83.4% higher than that of the Russia phosphate Nd:glass at the same pumping condition.

This paper first briefly overviews the current development of optical pulse offset frequency locking techniques, then summarizes the methods of discriminating frequency on optical pulse offset locking used in the techniques, and finally presents a wide-band all-digital frequency discriminating method (band width: 2～100 MHz) and design of a simple offset frequency locking system on the basis of the frequency discriminator. In addition,it also introduces the experiments on offset frequency locking between CW CO 2 laser and a pulsed CO 2 laser of which the pulse was produced by using a CdTe switch outside the optical cavity (optical pulse width: 5 μs and its repetition rate: 10 kHz). The experimental results were satisfactory, the beat frequency stability was 1.27×10 -7 (Allen variance).

Inner heat cycle of designed kW fast axial flow CO 2 laser is discussed, and the heat balance equation is eastablished. Technical key of heat exchanger for this kind of laser is given, and compared with several other kinds of heat exchangers. Rectangle fin circle tube heat exchanger is chosen as the laser′s radiator, and its conducting heat is calculated. The result indicates that the rectangle fin circle tube heat exchanger which has been chosen is suitable to our kW fast axial flow laser.

In this article, a novel ac electro-magnetic trap for neutral atoms is proposed, which is based on the interaction of a magnetic dipole moment of trapped atoms with both an ac quadruple magnetic field in the transverse direction and a dc-bias magnetic field along the axial direction. The result shows that this is an ideal strong field-seeking trap for cold atoms. An atom guide with radial trapping potential over 1.2 mK is obtained and the guided atoms can be confined in a small region of r～50 μm. With changing the distribution of the bias magnetic field, an ac magneitc trap of cold atoms with axial potential depth 0.5 mK and radial potential 0.6 mK can be got, which is high enough to trap nearly all atoms with a temperature of ～120 μK.

In this paper an application of the enhanced cavity in far detuning atom-lithography has been discussed. By reducing the Guassian beam waist and increasing laser power in the cavity, the requirement for the near resonant atom-lithography can be met. The numerical result shows that the FMHW of the lines deposited on the substrate at the centre of the laser beam in far detuning atom-lithography is much less than that in near resonant atom-lithography under the same angle deviation. So the enhanced cavity provides an approach to the atom-lithography.

In this paper, a new type of 1.5 μm InGaAsP integrated device was fabricated by using the ridge waveguide. The lasing was suppressed successfully without any AR (Anti-Reflection) coating on the output facet. No lasing mode was discovered in the range of measurement. Thus, the superluminescent power was improved significantly. Maximum power 110 mW was obtained.

Designing the optical elements of the "SHENGUANG" facility, ghost reflecting must be analyzed. By calculating and analyzing the ghosts of spatial filter in "SHENGUANG" facility, the lens style of the spatial filter, and the distance between the spatial filter and the main amplifier are eslablished.

Acoustooptic tunable filters (AOTF) based on MC (matched cladding), DS (dispersion shifted) and DC (dispersion compensation) fiber were studied. It is found that the fiber with large waveguide dispersion is a promising candidate to reduce the bandwidth of AOTF. In order to describe the relations between the fiber dispersion and the filters bandwidth, a dispersion parameter N is defined and its relation to the tuning rate of the fiber AOTF is derived. This allows one to estimate the dispersion properties of a fiber by using the more easily measurable parameter of tuning rate. Experimentally, as narrow as 0.55 nm of FWHM bandwidth was demonstrated on commercially available DC fiber.

This paper analyzes the superresolving property of conventional system combining with 3-zone phase-only pupil filter at special central intensity ratio. A calculated example is provided based on this analysis. The sidelobe of the system is too high to be used in conventional system, while in confocal scanning imaging system good superresolving effects is achieved.

The behaviors of platinum dissolution in N21 and N31 phosphate laser glass under different temperatures and oxygen bubbling conditions were investigated in this work. By measuring and comparing the optical absorption at 400 nm, the effects of oxygen gas flow rate, melting temperature, and processing time on dissolution rate of platinum in N21 and N31 laser glasses were examined. The relation between dynamic parameters of platinum dissolution (diffusion coefficient and activation energy) and melting conditions (melting temperature, processing time and oxygen gas flow rate) was disclosed. This provides important references for manufacturing platinum inclusion free neodymium laser glass used for high power laser.

Theoretical ab intio calculations for different symmetry groups of N 2 molecular dimer are performed. It is proved that the potential energy curves of N 2 molecular dimer with D 2h symmetry group have an excimer like a 1B 2g→a 1B 3u transition. The theoretical emission spectra for a 1B 2g→a 1B 3u transition is calculated. The experimentally observed spectra for N 2 molecular dimer is found to be in good agreement with theoretical calculations. The gain coefficient of N 2 molecular dimer at 336.21 nm is estimated. The gain coefficient is measured with amplified spontaneous emission method, experimental results correspond to the estimation in the range of error. In the end the output laser power is estimated.

Using type Ⅰ/type Ⅱ angle-detuning scheme for third harmonic generation,the effect of phase ripple on the characteristic of third harmonic conversion is considered and calculated when the input fundamental field is super-Gaussian beam. The results show that phase ripple affects both doubling and tripling efficiency and beam quality of harmonic waves.

In this paper, the experimental results of high-order harmonic generation in Kr using an 105 fs, 795 nm laser system are presented. The effects of gas densities, laser intensity and laser polarization on harmonic emission are mainly studied. At the same time, the results are analysed from theory. The results indicate that proper gas densities and laser intensity are needed in order to get stronger harmonic emission; besides having higher laser intensity, the detector of high sensitivity must be possessed in order to get higher order harmonic generation.

A simple means for investigating nonlinear process induced group velocity dispersion in CPPLN is proposed in this paper. It′s found that not only the second-harmonic pulse but also the fundamental pulse can experience dispersion in CPPLN under certain condition. The characteristic of group velocity dispersion in CPPLN is discussed and compared with that of conventional dispersion components.

The dependence of optical signal-noise ratio on the number of optical nodes, both noise figure and gain of EDFAs is derived. The relation between the number of optical nodes and specifications of EDFAs is analyzed. Followings are concluded: 1) The number of optical nodes is about 19 under the case where the first EDFAs of optical nodes are used for the loss of nodes and the second EDFAs for the loss of fiber, and where the OSNR is required more than 20 dB; 2) To modify EDFAs′noise figure increases the number a litter; 3) It can increase the size of the all optical network up to 56 by reducing the loss of the nodes and optimizing each gain of EDFAs as well.

An all-optical passive WDM upgrade of a passive optical network (PON) with an optical-fiber in-band WDM Coupler and a coarse WDM as multiplexers and demultiplexers is proposed and demonstrated. Using F-P lasers as the light source, the OLT and ONU can provide two additional wavelengths. The experiment demonstrates that the scheme can be with less optical power loss and crosstalk through selecting the proper wavelength of F-P lasers.

Multiple repetition rate (2～7 multiples of 2.5 GHz) synchronized reference-clock generation is demonstrated by use of fiber ring laser with an EDFA as gain medium and a SOA as gain modulation from an external 2.5 GHz optical pulse train generated by a GS-DFB laser.