High-order optical soliton compression effects in a loss fiber were analyzed in theory. 4.8 ps-pulses at λ=1.55 μm were obtained by using a F-P spectral window and high-order optical soliton compression from 44. 2 ps-pulses which were generated from a gain-switched DFB laser. The experimental resultS asree well with those expectedtheoretically.

A gain measurement technique with amplified spontaneous emission (ASE) has been applied to active fibers for the first time. In terms of a theoretical model,the relative gain of the Nd3+-doped silicate fiber at 1080 nm is obtained by using numericalcalculation.

A laser holographic method of measuring the surface Rayleigh-wave rate of the core taken from the oil-drill of Daqing is given. The measured results were analyzed and discussed.

A study on the thermal distortion of a GaAs output coupler with high reflection(HR) coatings in high power transverse-flow CO2 lasers is presented theoretically andexperimentally. Using a reasonable approximation, the GaAs coupler's temperature distribution and thermal distortion are given in formulae. The experimental data coincide well with the theory.

In this paper, the basic paper, the basic workin principle of an X-ray grazing mirror system is introduced. An emphasis is placed on the manufacturing technology of the super-highaccuracy mirror system. A Ni mirror system with less than 1.5 nm surface roughness has been made out. The reflectivity of the Ni mirror system is more than 54% at a 5°grazing angle.

Seventy patients with 316 tumors of urinary bladder have been treated by photodynamic therapy (PDT) with a gold vapour laser. All cases were histopathologically diagnosed as transitional cell carcinoma. The power output from the tip of an optic fibre was 2.0～2.5 W and the power density used was 70.8～509.6 mW/cm2. The pulse duration was 20～50 μs, the pulse energy was 0.5 mJ per pulse and the repetition rate was of 6000～9000 Hz. Both the tumors and whole bladder were irradiated. Hematoporphyrin derivative (HpD, Yanzhou Biochemical Pharmaceutics, China was given IV in a dose of 5 mg/kg in 250 ml of 5% glucose, 48 hours prior to irradiation. The results of a follow-up of 4～46 months are as follows: cured, 54 case (77.14%); good effect, 12 (17.14%); and improved, 4(5.7%). Tumor regrowth occurred only in 8 cases (11.43%) within 3～9 months after PDT. The results suggest an increase of cured ratio and a decrease of regrowth ratio and the reoccurrence ratio of tumors has compared with results obtained by other treatment modalities.

With a computer controlled excimer laser marking system, we studied marking processes of stainless steel. On the conditions of different laser fluences, the laser irradiated surface of stainless steel appears different. The marking threshold (the laser fluence corresponding to the melting point of iron) can be concluded by calculating the laser induced surface temperature. As the laser fluence exceeds the threshold a mirror surface appears, otherwise, an oxide layer will be formed. The calculation shows that the rates of surface temperature variation (heating rates or cooling rates) of 1010 ℃/s can be obtained, which neans a noncrystalline layer should be formed on steel.

After adjusting components of the Fe-base alloy powder which is used to clad bylaser, we find that crack direction and cracking sensitivity in laser cladded layers change with composition of the cladded layers. The included angle between the crack direction and the laser scanning direction decreases as Ni content in the cladded layers is increased. When Ni content is increased to above 15wt-%, cracks disappear. The reason for these results is that the crystallizing orientation of the overlapping zone is changed with changing of the amount of Ni in the cladded layers. So we think that controlling the crystallizing orientation of laser cladded layers is an effective method to decrease the cracking sensitivity of laser cladded layers.

In this paper, the change of nitrogen at different depths in 35CrMo steel through ion nitriding and laser phase transformation hardening treatments was investigated with Xrays Photoelectron Spectroscopy (XPS). The experimental results show that the deeper oxynitride layer beneath surface can be obtained by the composite treatment process, and the depth of the nitriding layer is also increased. There will be a deeper nitride layer formed through the composite process other than the conventional nitriding process.

A Nd: BEL laser pumped by a homemade laser deode is reported for the first time in China. An output of 1.07 μm linear polarization laser has been observed. Using two nonspherical lenses or plus an additional anamorphic prism or plus an additional optical fiber as the couplers of the pumping laser, three different slope efficiencies were obtained, and an analysis about it is presented.

Cr: LiCAF is a kind of very useful material for tunable solid state lasers. In this paper the laser performance of Cr: LiCAF is reported for the first time. The broad band emitting of 472 mJ with a slope efficiency of about 1.2% and the tuning range of 722～836 nm as well as a maximum output energy of 60 mJ at wavelength of 780 nm have beenobtained.

Studies on gain and saturation output characteristics of an erbium-doped fiber amplifier are presented in this paper. The amplifier is designed and constructed with low concentration EDF and bidirectionally pumped by two 1.48 Urn LDs. Net small signal gain of 26. 5 dB and the maximum net output power of 9 dBm have been achieved.

This peper offered a theoretical method for the analysis of distributed EDFA' s,which can analyze the signal gain and pump absorption of the amplifiers. With it, we can carry out the optimal design for distributed EDFA's. We derived the basic formula, and discussed it under some special conditions. This method is suited for amplifier systems pumped at 1480 nm and 980 nm bands.

The atomic coherence induced by simultaneous bilaser resonance in a V-type three-level system has been studied. The distributions of atomic POpulations are obtained by solving motion equations, and the atom trapping of sodium in two upper levels has been observed experimentally. A comparison of the change of populations in the state 3S1/2, F= 2 is performed under conditions of coherence and no coherence.

Analytic expressions for axial intensity distributions of a Bessel-Gauss beam focused by an aperture lens have been derived by using Coffins diffraction integral, and discussed by numerical calculations. As a limting case, the axial intensity distributions of a Bessel beam focused by an aperturelens have also been studied both theoretically and experimentally.

A "rapid" distorted wave method and our program MCDW (9) are used to calculate collision strengths of Mo32+ for the passible transitions from the ground state to excited levels. The results have been carefully compared with other full relativistic distortedwave ones that have been published in the literature. The discrepancies are generally within 10%, indicating that this procedure and program are not only rapid but also accurate.

Several Pr3+-doped fluoride glasses with different chemical comPOsitions were prepared. The absorption and fluorescence spectra of the glasses were measured, and some fluorescent properties of glass were calculated by using the Judd-Ofelt theoretical model. It is shown that the fluorescence properties of Pr3+ ion in fluorizirconate glasses are better than those in fluoroaluminate and fluoophosphate glasses, and the radiative transition probabilityand the stimulated emission cross section increase. Its fluorescence bandwidth decreases with the increased substitution of NaCl for NaF in the fluorozirconate glasses.