The relationship between the effective bandwidth and the close bandwidth in adaptive optics (AO) control systems is discussed. The bandwidth of an adaptive optics control system is cpmpared with PI controller or pure time delay compensative controller too. The conclusion is that the time delay in AO system is the limitation of Bandwidth, and an AO control system should have higher Effective Bandwidth and lower Close Bandwidth.

A vector theory for diffraction of multi step phase grating is presented. The half numerical method converts differential equation into generalized eigenvalue equation. At matching the boundary conditions in the longitudinal direction, a mode conversion matrix is introduced together with the reflection and transmission coefficient matrices. The iteration formula of the amplitude coefficient of the electric field are derived out. Finally the diffraction efficiency for each order of the transmission wave and the reflection wave are obtained in the any polarization.The computer program developed from the method has much less amount of calculation so that it can work on PC fast and stable. The method presented in this paper provides a simple fast algorithm to design binary optical element by vector diffraction. The results show that the scalar theory results differ greatly with that of the vector theory in the certain condition.

By using the generalized Huygens Fresnel diffraction integral, the focusing of high power laser beams with amplitude modulations and phase fluctuations passing a lens with a central obstruction aperture has been studied in detail. The beam focusability in the focal plane has been discussed. Numerical calculation results show the dependence of the power (energy) focusability on the obstruction ratio, truncation parameter, the amplitude modulation and phase fluctuation parameters.

By an example of Tetragonal structure, the principle and method are discribed by which the orientation of light can be derived from interference structure. We use crystal lattce analogy to the intensity distribution of interference structure. Those crystal planes should be selected such that their Miller indices are lower and the planes have high symmetry. An analytic solution then should be obtained by setting geometric relations between the crystal planes and the incident light. The advantages of this method are obvious compared to that of numerical analysis.

For planar waveguide with Kerr type nonlinear film and linear substrate and cladding, the propagation characteristics of TE modes are analysed by KBM method in perturbation theory. The dispersion equation and modal field function are given by second order approximate formulas. The computation is greatly reduced and the results are exact. Typical examples for symmetric and asymmetric nonlinear waveguides are given.

The ion implanted planar optical waveguide in crystal LiTaO 3 was formed by implantation of He + at an energy of 2.8 MeV and with a dose of 1.4×10 16 ion/cm 2 at 300 K. The modes were observed and measured by prism coupling method. The refractive index profiles of the waveguide were calculated and compared before and after annealing. The damages on the crystal surface caused by the implantation of He + were firstly investigated by using RBS/channeling technique.

By using white light fiber optic Michelson interferometer, the temperature and strain coefficients of fiber optic refractive index were determined via the measurements of optical path changing as a function of temperature or strain. The results shown that the temperature and strain coefficients of fiber optic refractive index were 0.762×10 -5 /℃ and -0.1332×10 -6 /με for 1300 nm wavelength and 0.811×10 -5 /℃ and -0.1649×10 -6 /με for 1550 nm for the type SMF 28 single mode communication optical fiber, respectively. The measured results were compared with published data.

A novel, flexibly scalable optical separated Crossbar network configuration is proposed. Optical sub system is physically implemented. We present experimental results of the optical sub system. Network configuration of separated Crossbar employs the SEED devices as high speed optical modulators and the FET SEED device integrated on a single GaAs chip as optical logic array. This configuration solves the problem that a Crossbar is hardly scalable by employing flexible code rule and one, two or four FET SEED chips to provide scalable optical channel receivers. But the size of the separated Crossbar is limited within 32×32. This network configuration is especially promising in network computing application based on distributed computers. And it is competitive in realization of Cross connect matrix of SDH Cross connect system.

A method of collimating optical systems by a heterodyne interferometer is described and the errors of the system measurements are analyzed. It is shown that the errors can be eliminated as long as well controlling the tilt or the light quality. The experiments prove that the measuremental error is close to the resolution of the detector.

We derived the point spread function of rough wavefront from the Fraunhofer diffraction integration of rough wavefront. The integration result consists of an “optical kernel” and a “faint ring”. When the roughness increases, the former decreases, but the later increases.

A systematic analysis and optimizing design have been conducted for the integration of Si 1-x Ge x optical waveguide and Si 1-x Ge x/Si multiple quantum wells (MQW) infrared detector at λ=1.55 μm operation. The optimizing design results are: (1) For Si 1-x Ge x optical waveguide, Ge content x=0.05. Rib width, height and etched depth of the waveguide are 8, 3 and 2.6 μm, respectively; (2) For Si 1-x Ge x/Si MQW infrared detector, Ge content x=0.5. Total thickness of the detector is 550 nm, which consists of 23 periods 6 nm Si 0.5 Ge 0.5 +17 nm Si. The length of the detector is about 2 mm. The results show that the internal quantum efficiency of such structure devices can be as higher as 88%.

Continuously tunable and arbitrarily shaped electrical pulse is obstained using specially designed microstrip transmission lines. Based on the optimal theory we designed and discussed four microstrip transmission lines which corresponding to the four main electrical pulse shapes. The tunability and pulse shape are obtained satisfactorily.

The ray tracing and Monte Carlo method are applied to calculate the distribution of deposited pumping energy within a rod amplifier of the high power solid state laser system. Allowances are made for the effects of multiple reflections on the reflector and laser rod, Xe flashlamp emission spectrum and absorption spectrum of Nd doped laser glass. The results obtained are good agreement with the experimental results of gain uniformity measured by threshold method and laser wavefront measured by Hartmann wavefront sensor.

The linewidth reduction of a external cavity semiconductor laser with strong optical feedback is analysed. The effects of residual reflectivity r 2 of the AR coated laser facet, external cavity reflectivity r 3, and external cavity length L ex on the linewidth are studied theoretically. A fiber grating is coupled to a conventional multi longitudinal mode semiconductor laser with on facet AR coated. Single longitudinal mode operation with side mode suppression ration over 30 dB and linewidth below 120 kHz is achieved.

This paper presents new results obtained recently in studies of separate confinement structure (SCH) InGaAsP/GaAs lasers. Using Russia′s technology, the InGaAsP/GaAs lasers based on QW structure can be produced by short time liquid phase epitary (STLPE) employing a modified sliding boat technique. The interface abruptness in the InGaAsP/GaAs lasers can be made comparable to the lattice constant. Using 〈100〉 GaAs substrates, InGaAsP/GaAs SCH SQW lasers were fabricated and the followig values of the main parameters were obtained: lasing wavelength λ=808 nm, threshold current density J th =300 A/cm 3, CW power high to 1￣2 W for the laser with stripe width W=100 μm. 1000 h lifetime tests have been performed and the factors which affect the lifetime of the lasers are discussed.

The dependence of the output of self pumped phase conjugation (SPPC) on the different cutting methods of Ce:KNSBN crystal is analysed. The conjugate reflectivity up to 57.16% in a Ce:KNSBN crystal with a 18° angle between crystal axis and crystal surface is reported at a 514.5 nm Ar + laser. The phase conjugate reflectivity is proved connecting with the incident angle and incident position by experiments. Increasing the incident intensity, the response time of SPPC is demonstrated decreasing.

A femtosecond time gating of cross correlation second harmonic generation is shown to be a versatile technique to image objects through various highly scattering medium, and optical coherent tomography (OCT) is achieved preliminarily. The ballistic and snake pulse component, that contain the information of the objects are effectively selected, while the diffuse component which contributes bright background noise to the image is eliminated by time gating of femtosecond cross correlation second harmonic generation. The SHG one dimensioanl and two dimensional pictures of objects hidden in highly scattering medium are recorded, respectively.

A Cd x Zn 1-x Te/ZnTe multiple quantum well (MQW) optical bistable device has been fabricated, and its optical bistability is investigated at room temperature. The result indicates that the threshold and contrast ratio for the optical bistability in Cd x Zn 1-x Te/ZnTe MQW optical bistable device are about 363 kW/cm 2 and 4:1, respectively. On the basis of the excitonic nonlinear theories, excitonic absorption spectrum in the Cd x Zn 1-x Te/ZnTe MQW, we attribute the major nonlinear mechanism for the optical bistability to the saturating effect of excitonic absorption.

The sol gel process of C 60 NH 2(CH 2) 3Si(OC 2H 5) 3(C 60 3 Aminopro pyltriethoxysilane or C 60 KH550) mixing with CH 2OCHCH 2O(CH 2) 3Si(OCH 3) 3 (3 Glcidoxypropltrimethoxysilane or KH560) and (CH 3) 2Si(OC 2H 5) 2 (Diethoxy dimethymethylsilane, DTDS) were reported. The ormosils connecting with C 60 possessed good flexibility and mechanical strength. BET experiment showed that these materials have quite small pore. The compound can be polished on the machine. By using a Nd:YAG laser with 10 ns pulse duration and 532 nm wavelength, the optical limiting behavior of C 60 connecting with gel net was measured and demonstrated.

Laser ionization mass spectrometry is used to study the wavelength dependence of resonance-enhanced multiphoton ionization (REMPI) of methylamine, and both the parent and fragment ion yields are recorded in the wavelength range of 425～495 nm. Similarities in the REMPI spectra of all the ions could lead to greater trace detection sensitivity if the total ion yield is concerned instead of only the parent ions.

In WDM, FDM and soliton optical fiber communication system, the tunable F P cavity is a key device. In this paper, the factors of designing a high quality F P cavity are analyzed. Two advanced methods , the match method and diaphragm method of making F P cavity are combined. A high quality cavity is obtained and has been used in our optical fiber communication system as a demodulator.

A kind of near white emitted organic LED with structure of ITO/SA/PBD/Znq2/Al has been made. Here SA, a styryltriphenylamine derivative, is N (2 p methelphenyl) styryl N p methoxylphenyl beneneamine, PBD, a oxadizole derivative, is 2 (4 t butylphenyl) 5 (4 biphenylyl) 1, 3, 4 oxadizole, and Znq2 is 8 hydroxylquinoline Zinc chelate. The EL performance of single layer diode (SLD), double layer diode (DLD) and triple layer diode (TLD) have been investigated. The variation of EL spectra of two kinds of TLD′s with different thickness of organic layers by change the driven voltage indicates that the near white emission come from the recombination of electron and hole in both SA layer and Znq2 layer. The current density voltage (I V) characteristics and the brightness voltage (B V) characteristics of the single, double and triple layer devices have also been investigated in deteil.

Bacteriorhodopsin is a kind of biomembrane protein molecule which can store and convert photoenergy. On light illumination, it generates a rapid charge separation and protein electric response signals, which differs from that of the common inorganic photoelectric material. Through electrophoresis method, oriented bacteriorhodopsin films are deposited on ITO conductive glass, with which and a copper electrode, a photodetector with bacteriorhodopsin films and conductive gel sandwiched is constructed. The photodetector′s response to 532 nm wavelength, 30 ps ultrashort laser pulse is studied experimentally. The mechanism of the photodetector′s photoelectric response is theoretically analyzed.

The EIS type Light Addressable Potentiometric Sensor (LAPS) system is described. On the basis of experimental data, Authors analyze such parameters as bias voltage, light modulation frequency, light radiation power, which have great relationship with the EIS type LAPS′ photovoltage. Consequently, the optimized result of these parameters is given. A super Nernst function phenomenon in the relationship of photovoltage and pH value is reported.

A two mirror aspheric optical system has been designed for soft X ray reduction lithography. The designed optics achieves a defraction MTF value of over 0.5 at 13 nm wavelength and at a spatial frequency of 5300 lines/mm capable of resolving <0.1 μm lines and spaces within a flat field of φ30 mm. The reduction ratio is 1/6, working F/# is 2.554 and the maximum distortion is 0.04%.

The time resolved Monte Carlo method is used to study the time domain characteristics of light pulse propagation in tissue. The simulation results of Monte Carlo method are compared with the analytic results of diffuse theory. The relation between the optical parameters of tissue and the time resolved reflectance on tissue surface is discussed. The results illustrate that the time of maximum reflectance is mainly affected by the scattering coefficient, the slope of the reflectance decrease is mainly affected by the absorption coefficient. The g factor only affects the early data of the time resolved reflectance. The results in this paper show more promise to apply in the noninvasive measurement of the optical parameters of tissue and the oxygen saturation in arterial and skeletal muscle.

The focusing theorem in the metric optics is derived. The conditions of focusing, defocusing and trapping of light beam are given. Its application in a static axial symmetric medium is discussed and analysed.

By using a new parametrization way, =(q y-1)/(q-1), the q Boson annihilation operator was defined, and a new q coherent state was constructed. The system Hamiltonian that can produce and maintain the q coherent state was found. We studied the mathematical construction and the quantum fluctuation characteristic of the orthonormalization eigenstates of a q k (k≥1). It is found that the only even q coherent states have usual squeezing effect, and when the parameter q<1, the quantum fluctuation of both quadrature components of the field for each state may be simultaneouly smaller than the minimum uncertainly value (1/4) of the coherent state. These eigenstates have q squeezing.

The Mandel factor for the single mode laser field is derived analytically, and te pump condition for generating sub poissonian distribution is given based on abover results.

The experimental results of the wavelength conversion by employing a light injection DBR laser diode at 2.5 Gb/s are presented, which can be used in optical communications.

The Raman spectra of berring sperm DNA in antive fibers and after heat treatments to 40℃, 91℃, and 200℃ were presented. The Raman spectral bands indicated that the damage of the heating on the DNA conformation is limited below the melting point. The damage of the DNA molecular structure increased with a rise in temperature above the melting point. The damage was first obversed in adenine and deoxyribose. The Raman spectra of DNA in aqueous solution and after ultraviolet radiation were reported. The experimental results proved that ultraviolet radiation had a serious influence on the DNA molecular conformation and damaged the hydrogen bonds and groups among the purine and pyrimidine bases. The denuturation was irreversible.

Luminescence from porous silicon is studied with plane polarized light excitation under grazing incidence. The experiments show that the incident angle of light almost has no influence on the luminescence behavior of porous silicon. However, the luminescence with z polarization excitation is found to be higher in intensity than that with x polarization excitation. The different orientations of the electric field of the exciting light with respect to the sample surface result in the difference in the excited luminescence, which reveals the anisotropy of the optical properties of porous silicon and rules out the assembly of pure quantum silicon dots as the structure of porous silicon.

Nanocrystalline Ge SiO 2 thin films were successfully prepared by the ion beam sputtering technique followed by annealing. Optical absorption spectra of the Ge crystallites of size 3 to 9 nm in diameter, on the average, have been studied. In comparison with that of the bulk Ge crystals, the nanocrystalline Ge show a blue shift of energy and the optical band gap increases with decreasing of the particle size of the nanocrystallites. The effective mass approximation model based on the quantum size effect is suggested to discuss the observed optical experimental details with satisfaction but only qualitatively. An effect of the dielectric confinement of the Ge nanocrystallites on the optical absorption spectra was observed.