A systematic analysis and optimum design have been reported for the integration of the Si1-xGex optical switch and the Si1-xGex/Si infrared detector at λ=1.55 μm. The optimizing design results are:(1) For the Si1-xGex optical switch,Ge content x=0.05. Waveguide height,width and etched depth are 3, 8.5 and 2.6 μm, respectively, branch angles are 5～6°, and the bias voltage of pn+ junction is 0.97 V.(2) For the Si1-xGex/Si infrared detector, Ge content x=0.5. Total thickness of the detector is 550 nm, shich consists of 23 periods alternate 6 nm Si0.5Ge0.5 +17 nm Si. The length of the detector is about 1.5～2 mm. The results show that the internal quantum effciency of the detector of this structure can be as high as 80%.

8×8 multiple quantum well spatial light modulators (MQW SLMs) are designed and their breakdown voltage, ASFP mode, contrast ratio and insertion loss are measured. An optical interconnection pattern is implemented in which 8×8 optical beams are generated from a semiconductor laser by using a Dammann grating and are routed to the 64 windows of 8×8 SLMs. Through this architecture, modulation characteristics of 8×8 SLMs can be measured.

Computer stimulation shows if the LP 02 mode is suppressed and only the LP 01 mode is transmitted in a two mode dispersion compensating fiber of three clad dings, more than thousands ps/nm·km negative dispersion values can be achieved. Having a large mode field, small bending loss, small polarization mode dispersion and small temperature drift, and the loss value as other dispersion compensated fibers, the fiber of this kind appears to be a promising dispersion compensating fiber.

When there are distortions in transparent media, a light through uniform parts and distortions of the media will overlap each other after the transformation of a lens. By the amplification of LiNbO 3:Fe crystal placed at the place where the two kinds of lights coincide, the contrast of the transmitted pattern will increase greatly and then we can detect the distortions in the transparent media. This method is quite simple and has high sensitivity.

In this paper, the transmission situation of a ballistic light carrying the information of the object image in fog is analyzed. Its intensity reduction and traveling distance limitation are discussed. This new kind of experimental method based by the characteristic of a polarized light is presented. The experimental result which is in good agreement with theory is given. The probabilities of increasing signal to noise ratio and enhancing the quality of an imaging in fog with this experimental method are discussed.

The self imaging functions which can self image on scale are shown. Then we apply them to the optical interconnection of neural network. Consequently, the optical interconnection system is simple and the experimental operation, especially the optical adjustment is easy. Finally, the experiment is shown.

This paper introduces a kind of image processing method for laser fusion experiment. Since the image of the hohlraum hole is dim and its brilliance distribution is non uniform a technique to determine the geometric center of the image is thus necessary. Application of the technique to the target pointing in the Shenguang Ⅱ project is also included.

In this paper, the mesospheric sodium data, observed from Mar. 1 to Mar. 3 1996 in Wuhan (30°32N, 114°22E) by a laser radar, have been analyzed, and the distribution of the Na atoms density with the altitude and the relation of the profiles of the Na atoms density with time have been got. The results point out that the distributions of the Na atoms density change vs time apparently. The sodium layers lie between 80￣105 km, and the maximum Na density lies between 92￣95 km, its value varies from 1×10 9 to 3×10 9 atoms/m 3 when there are no meter rains.

A method for microdissection, isolation of chromosomal fragments using a laser beam incorporated with a microglassneedle was established. Firstly, a 7H chromosome of Hordeum Vulgare L. was dissected by the Nd:YAG laser beam of suitable parameters; then the fragment comprising a satellite was isolated and put into an eppendorf tube by a micro glassneedle fixed on a micromanipulator. This research provides a new method for the microdissection of special chromosomal regions.

The photodynamic effects of fullerene (C60) on the calf thymus DNA with FT Raman spectroscopy at the molecular level has been studied in this paper. The spectrum showed that the photoexcited C 60 damaged almost all of the component groups of DNA to different extents. The conformation of DNA has been changed considerably by weakening the bases stacking and hydrogen bond, meanwhile the adenine and guanine are destroyed greatly. With increasing the concentration, C 60 induced a cleavage of the DNA strand by damaging the phosphate backbone and deoxyribose. The photodynamic damage to DNA by photoexcited C 60 was induced from singlet oxygen(1 O 2)and ·OH, O 2·－.

An optical system is designed and fabricated on the basis of the target scattering characteristics and the edge tracking concept. This system is the optical head of a frequency modualated continous wave CO2 laser radar in which only a single mode CO2 laser is used. Using a collimator tube, the tested minimum light speckle on the focus plane is 50 μm in diameter. The acceptable error signals are engendered when a slender laser beam of 0.12 mrad angular divergence is directed on the diffuse target edge. The backscattered signals from building at 7.8 km are obtained with a fairly good SNR when the laser output is about 5W.

A diode laser pumped Nd:LMA laser was reported, in which a CW power of 650 mW with a slope efficiency of 33% at 1.054 μm was demonstrated. Using a fiber nonlinear additive cavity, self starting additive pulse mode locking was realized. Near transform limited pulses as short as 1.8 ps with an average power of 58 mW were obtained from the laser.

In this paper, a tunable Q switched flashlamp pumped Cr 3+ :LiCaAlF6 laser is introduced. The tuning range of a Cr 3+ :LiCaAlF6 is determined to be at least 730￣850 nm. The free running lasing wavelenth of the Cr 3+ :LiCaAlF6 is 780 nm. When the input pulse energy is 292 J, the highest output energy is 1.62 J. A slope efficiency is 0.8%. The threshold energy is 50.4 J. The Q switching of the Cr 3+ :LiCaAlF6 is performed with a KD*P crystal. The single pulse width is 48 ns and the highest output power is 1.3×106 W.

The high power external cavity semiconductor laser has become an important optoelectronic device. In this paper, using a grating as the feedback component, a laser of single frequency output over 70 mW and side mode suppression over 30 dB is reported. Meanwhile, some parameters which influence the performance of the high power external cavity laser are analyzed.

A JK 13 across flow CW 2 kW CO 2 laser of tube plan low gas pressure discharge structure, using argon helium mixing gas, was studied. The substituted amount of He gas (Ar doped amount) increased from 20% to 60%. When the working gas pressures were 2.93~4.26 kPa and the discharge currents were 3~11 A, the laser discharged steadly and operated normally. An output power of 1.7 kW and an effciency of electro optic conversion of 16 percent can be obtained.

This paper introduces a switching power supply for a repetition rate flashlamp pumped Ti:sapphire laser. It includes a switching circuit at PWM mode and a double prefiring circuit. This power supply is capable of giving an output power of 2 kilowatts at a repetition rate of 5 Hz.

Anisotropic self diffraction in doped KNSBN crystals has been observed when an external electric field is applied for the experimental configuration where the c axis is parallel to the incidence plane. The coupled wave equations and their numerical solutions including the space distribution of a grating vector and the second order space electric field are presented. Both theoretical analysis and experimental results show that the anisotropic self diffracted light arises from the contribution of both incident beams.

The experimental results of radial distribution of Langmuir flow effects in a ring laser gyro are reported in this paper. They show that it is mainly the motion of upper and lower laser level atoms contributes to the ring laser gyro output. Therefore, the discription about the radial distribution of the Langmuir flow effect before is incorrect for laser gyros.

An analytical method for treating the problem of the laser heating and melting is developed by suggesting a simple and reasonable temperature profile form. Temperature distribution in a material before melting as well as after melting is given and the movement of the phase interface is also obtained. As an illustrative example, computations are carried out on a silicon material and the results are in good agreement with those obtained by other authors.

This paper uses a space ray tracing method of geometrical optics and light diffraction theory to study a wideband laser beam transformation system which has been applied to the laser heat treatment. The results are compared with the experimental observations.