A design of LD-pumped Nd∶YVO_4 laser that generates simultaneous laser action at the wavelengths 1064 nm and 1342 nm by optimizing film design is presented .An optimized CW 593.5 nm yellow laser at room temperature is obtained for the first time.Using type-I critical phase-matching LBO crystal,593.5 nm yellow laser is obtained by 1064 nm and 1342 nm intracavity sum-frequency mixing.The maximum laser output power of 85 mW is obtained when a incident pump laser of 1.8 W is used.The optical-to-optical conversion up to 4.7%,the power instability in 24 h better than ±2.8%.

The general solution of crystal under TEM_ 00 with rectangular section interior temperature field distribution was obtained by a new semi-analytical thermal analysis method. Subsequently some relevant parameters,which would influence temperature field distribution, were analyzed.And discrepancy between the rectangular section crystal and the circular section crystal was compared.Research results will be theoretically established for further research,such as phase mismatching induced by non-uniform temperature raise,and play instructive effect at improvement of DPSSL′s output power.

By considering the Gaussian spatial distribution of the intracavity photon density and the thermal effect in the gain medium,the coupled rate equations of a LD-pumped passively Q-switched Nd∶GdVO_4 laser at 1.06 μm with Cr 4+ ∶YAG are given. The theoretical pulse width,pulse repetition rate,single-pulse energy, and peak power of the laser are obtained by numerically solving the rate equations.The theoretical calculations agree with the experimental results.

Applications of confocal scanning microscopy and low coherence tomography in the biological and material sciences for optical-sectioning imaging require focusing light into the bulk specimen.However, the differences of refractive indices among biological tissues,the cover slip and immersion medium cause the strong spherical aberration and make the electromagnetic distribution in the focal region distorted.The spherical aberrations caused by focusing the light deeply into the specimen through multi-layer medium with different refractive index are analyzed. The results are used to calculate the limit penetration depth of microscopic imaging caused by focusing light into the bulk specimen through planar interfaces between materials of mismatched refractive index.The effect of spherical aberration on electromagnetic distribution in the focal region is also discussed.

It establishes the theoretic model to make vessels in myocardium by infrared laser according to regularity of laser-myocardium interaction and thermodynamics.It deduces quantitative relation of vessel depth and time to make a vessel in myocardium. It does the experiment to make vessels in myocardium of pigs by 100 W CO_2 laser and the results indicate that the experimental result and the theoretic result are alike within a certain range.

A polarization controller composed of four electro-optic crystal plates which phase delay can vary from 0 to 2π is proposed, and simulated annealing algorithm is taken on as feedback control in this controller. Simulated research shows that this controller is endless and the output polarization state is stabile while the light intensity fluctuates less than 1%. The research on control parameters indicates that the initial temperature about 0.1 and the temperature transforming function T_ k+1 =0.2T_k are required for this controller. The state generating constant s sharply influences the convergence and its better range is between 0.005 and 0.01. To reduce running time, the repeat number 9 is introduced for once search.

LPFGs written by high-frequency CO_2 laser pulses have great potential for use in optical fiber sensing and communication. It is of importance to study the fundamental characteristics of these novel LPFGs. In this paper, a more systematic analysis is carried out to investigate the resonant wavelength-bend sensitivity of the LPFG and its bend loss of resonant peaks based on the mode field theory. It is for the first time to our knowledge, that a method is proposed for analysis of the orientation-dependence of the bend of the LPFG. The simulation is in agreement with experimental results. This paper provides a more systematic analysis for the bend characteristics analysis of the LPFG written by the high-frequency CO_2 laser pulses exposure method.

This paper point out the main reason that integrated optic device′s stability influences the stability of fiber optic gyroscopes , though the research of the integrated optic device′s characteristic . The method is design to track and compensate instability of the integrated optic device modulate degree in real time . The design is qualified and proved its validity though plentiful experiment .It can improve the stability of fiber optic gyroscopes.

A more accurate analytical expression for the noise figure of fiber Raman amplifiers is derived. Then the impact of multiple-path interference induced by double Rayleigh scattering on the noise figure of fiber Raman amplifiers is studied. The results show that impact will be more serious when the fiber length, input signal power and Raman gain are increased. But the results also show that if the fiber length is optimized and Raman gain is properly controlled one can achieve the best trade-off between the noise and Raman gain.

The modes configuration of the electromagnetic field of the signal light and the pump light within rib Er-doped Al_2O_3 waveguide amplifiers were analyzed using the finite element method. The population distribution of the five-levels system for Er 3+ with 980 nm pump was solved using its rate equations. The relationship between the net gain of the waveguide and the signal power, and net gain characteristics of two or three rib Er-doped Al_2O_3 waveguide amplifiers in series were numerically simulated. The results show that there are two kinds of net gain losses. In the series system, the better total amplification ability can be obtained when the waveguide amplifiers with low-concentration is taken as a preamplifier than it is taken as a post-amplifier.

The Fiber Bragg Grating (FBG) is very important in the applications of fiber communication and fiber sensor nowadays. The key technique of such applications is the wavelength tuning of FBG. Hence many tuning methods are put forward and worked practicably now, but they still meet disadvantages of complicated structure, lower accuracy and so on. Therefore, FBG encapsulated with sealed shell groupware of semiconductor light source is introduced in this paper. It also put forward the method of completing double direction temperature tuning of FBG, with semiconductor cooler and negative temperature coefficient resistance (NTC) cooperated with peripheral circuit. A sealed sample of FBG with metal shell is designed and manufactured. The structure of the sample is very simple. In addition many temperature experiments are carried on at different environmental temperature of 0℃,20℃,40℃. The tuning range of FBG temperature is from -20℃ to 60℃ with a 10℃ step. These experiments demonstrate ......

It is proposed a new structure of the retro-reflection plane material, in which the gradient index micro-spheres substitute for the traditional homogeneous glass spheres with high refractive index. Using the theoretical calculations of the light tracking by quadrivalence Runger-Kutta method, the technical condition of the retro-reflecting plane material of GRIN micro-sphere is obtained. The result shows that on this condition the former high demand for refractive index of medium can be highly reduced, and the function of retro-refraction of the material is improved greatly.

A concise analytical method (extending coefficient) of coupling between two nonparallel waveguides is reported in this paper. By this method, a novel coupled equations are derived for two non-parallel waveguides. From this, the perfect analytic solutions between two nonparallel waveguides are obtained. In according with these analytic solutions, the propagation distance and spaces of input/output-guide ports and angle may be optimized for the nonparallel waveguide structures.

Experimental dependences on bias current and physical mechanisms of 1/f noise and g-r noise (generation-recombination noise) in Optoelectronic Coupled Devices (OCDs) are studied. Experimental results demonstrate that g-r noise of OCDs emerges with 1/f noise in the range of low frequencies and both of them have a similar rule, that is to say, in the beginning, magnitudes of g-r noise and 1/f noise increase and then decrease with the bias current keep increasing. From measuring noise of the front part and back part in OCDs, it is found that g-r noise source in OCDs lies in the photosensitive transistor. Based on mechanisms of carrier fluctuation, it is discussed that 1/f noise in OCDs belongs to surface 1/f noise and g-r noise is due to trapping and detrapping processes between carriers and deep-level in the emitter space-charge region of photosensitive transistor.

A novel optical tunable filter based on liquid crystal technology is reported in this paper. The structure and principle of this novel liquid crystal tunable filter are presented carefully, and then the optical signal transmission matrix and expression are deduced by the Jones Matrix way, the modulated characteristics of the LCTF′s amplitude and phase are achieved by numerical simulation. The DGE based on eight cascaded LCTFs are analyzed and emulated with genetic algorithm, and the experiment of DGE is realized with the parameters of the simulation results, the whole optical transmission spectrum are gained, and these experimental results agree well with the theoretical analysis.

A novel optic fiber interferometer for distance measurements over a wide measurement range using an artificial neural network is designed. The optical phase of the interferometer is simultaneously modulated with a frequency modulated laser diode and optical path-length difference. To enlarge the measurement range and eliminate the influence of the cross-sensitivity, the interferometer readings are used as input data and the actual sensed measuring value as desired output data during the training process of the network model. The principle and signal processing system containing the ANN are described. The experimental results show the use of ANN could widen the measurement range and enhance the measurement accuracy.

Optical thin films exhibit inevitable polarization effects at oblique incidence, which leads to the spectral splitting of s-and p-polarization components. Generally, s-polarized light initially enters Philips prism, and then the light is modulated to p-polarized light by liquid crystal light valves if they are in "on state". Consequently, minimum splitting of s-and p-polarization components is required to gain optimum efficiency and improve contrast of the system. The novel design method is based on a broad-band F-P thin film interference in which both sides of transmittance band can be used for long-wave-pass or short-wave-pass filters, and through suitable refinement it is possible to achieve zero separation between two polarization components.

Thin film filters were prepared by evaporation method, and the samples were soaked in DI-water for 10 days and 30 days respectively. By using spectral photometer, dark field microscope, and scanning electron microscope, stability of induced transmission filters in moisture environment was studied. The experiment results show that the layers delaminations of filters often initiate and expand from microdefect sites in the films in moisture environment. Microdefect in thin films is one of the most important influence factors on the filters environment stability, and impurity and pinhole are two main sorts of defects in thin film filters. EDS energy spectra analysis indicates that component of the impurity is Al_2O_3 coating material itself. So it is reasonable to deduce that the sputtering in film position process may be the original reasons for the defects generation, and sputtering restraining is a useful method to improve the stability of the optical filters. At last, the diffusion theory was used to analysis the ......

Owing to Micro-mechanical silicon membrane structures micro size and fragile properties, the method to determine Young′s moduli must be non-contact and nondestructive. Based on the photo-thermal effect, a novel method was presented by using optically excited resonance and optical fiber sensing techniques in this paper. This new method utilizes first three resonant modes of the fabricated silicon membranes to get a more accurate evaluation of Young′s moduli, and a novel optical exciting and sensing system using only one optical resource was set up to make the evaluation more practical.

Grating lenses have been widely applied to various optical system because of their special optical characteristics. Theoretically, the grating lens is subdivided into smaller sub-areas in this paper, and every sub-area is regarded as periodic micro-structure, according to lightly variance of adjacent linewidth. Rigorous modal theory is used for analyzing their diffractive properties in sequence, and finally total diffractive efficiency of grating lenses can be easily obtained. Numerical simulation is performed to calculate diffractive efficiency of grating lens, which is used for beam sampling and harmonic separation in high energy laser system. It shows that results computed by the method in this paper are accurate and valid. In addition, fabrication-process-tolerance effects on diffractive efficiency are also discussed. In experiment, a beam sampling grating with diameter 100 mm was fabricated, and its experimental diffractive efficiency is consistent with result calculated by the method in this paper.

By using the linear approximation method, the intensity correlation time is studied for gain-noise model of a single-mode laser driven by white pump noise and white quantum noise with colored cross-correlation. It is detected that the noise correlation coefficient has a great effect on the curves of the intensity correlation time upon the noise intensities. When the noise correlation coefficient is positive, there exist maximum (i.e., resonance) in the curves of the intensity correlation time upon the noise intensities. When the noise correlation coefficient is negative, there exist minimum (i.e., suppression) in the curves of the intensity correlation time upon the noise intensities. And when the noise correlation coefficient is zero, there are neither maximum nor minimum in the curves, the intensity correlation time increases monotonously with the increasing of the noise intensities. Furthermore, the effect of the cross-correlation time, the attenuation coefficient and the signal frequency on the intensity

In this paper, the effect of amplifier spacing on the performance of average-soliton transmission system using PSA as in-line amplifiers has been analyzed theoretically by computer simulation. Our simulation results show that when the ratio of amplifier spacing to dispersion distance is below 0.1, the performance of soliton system is well enough. But when it is above 0.1, the system performance is deteriorated quickly. The reason is that due to the phase sensitivity of its gain, PSA can cause soliton energy loss, thus result in the amplitude of soliton pulse descending significantly after long distance transmission. Raising PSA′s gain a little can compensate the loss, thus improve system performance. But the improvement is at cost of heightening the wing amplitude of soliton pulse.

A novel all-optical clock recovery scheme based on “Intensity reshaper” and mode-locked semiconductor fiber ring laser is demonstrated for equal-amplitude even-multiplexed OTDM signals, which simplifies signal generation and propagation in high-speed OTDM systems. In theory, a mathematical expression is given about the intensity of harmonic of clock-frequency component. The relative intensity of every frequency component will change by adjusting the PC in the “Intensity reshaper”, so the desirable clock-frequency component can be enhanced, which is helpful for clock recovery. In experiment, 2.5 GHz frame clock and 20 GHz bit clock are extracted from equal-amplitude even-multiplexed 8×2.5 GHz OTDM signal by using this scheme. The extracted clock pulses have several desirable features such as low timing jitter, broad wavelength tuning range and polarization independence. This technique can be applied to clock recovery in high-speed OTDM network.

A novel prioritized scheme applied to contention resolution was proposed for optical burst-switched networks. Performance analyses show that our proposed scheme works very well. The average delay and the burst loss probability of the higher-prioritized bursts are much less than those of the lower-prioritized bursts. The scheme can provide the good guarantee of QoS for optical burst with vital data and information.

Fabricated artificial opal templates, Low pressure metal-organic chemical-vapour deposition has been used to infill the voids within opals and optimized the growth parameters. Scanning electron microsocopy images and reflection spectra ruselts show that the InP is very homogeneously distributed inside the opals, with high crystalline quality;the photonic band gap is shifted to higher wavelength as a result of the high contrast of dielectric constants when InP is introduced, which is in agreement with theoretical calculations.

GaInP_2 materials had been obtained on Ge substrate (100) toward (110)miscut 9 degree by a home-made low pressure MOCVD system.Its growth condition was investigated,and the testing results show that growth temperature, Ⅴ/Ⅲ ratio and growth speed influence on surface morphology and solid composition of GaInP_2.The measurements indicate that growth temperature should be 650～680℃, Ⅴ/Ⅲ ratio should be 180～220, growth speed 25～35 nm/min. And the results shows that the nearly similar performance of GaInP_2 is obtained on both GaAs and Ge substrate.

Establishing datum plane is the base assessing surface parameter. It is important to set up perfect datum plane in engineering measurement as well as geometry parameters′ shape and positional error inspection. In order to establish high precision laser scanning plane, the laser beam transmission is anatomized in the formation of the scanning plane. Based on the vector law of refection in optics, the scanning error′s academic formula is educed. The essential principle on the error compensation is given. The academic formula is educed which is used to compensate the error of the scanning equipment. According to the academic formula, the model of the scanning equipment is designed. The analysis indicates that when the plane is set up by means of laser scanning equipment, scanning error is unavoidable; if the error were not compensated, it would come into the datum optical plane and would influence on the accuracy of the datum plane, thereby the parameter evaluation accuracy would be played down; by means of the

A kind of measuring instrument based on F-P interference wave length is designed.The measuring instrument use double interference cavities.One of interference cavities is reference cavity,the other is measuring cavity.One reflect surface of reference cavity is installed with piezoelectric ceramics,One reflect surface of measuring cavity is erected with an object to be measured.When the central wavelengths in reference Fabry-Perot interference and in measuring Fabry-Perot interference are overlapped,there are the maximum light signal outputs. Based on the relationship between the transmission spectrum central wave length and its interference cavity length, this measuring instrument can be used to realize the real time measurement of Nano-grade micro-displacement.Using simi-conductor laser as the light resource can obtain the required wavelength values and its variation scopes.It can be seen from the measured results that the measured error is not over 1.5 nm. Such a precision can satisfy the precision requirements as in the ......

Theoretic optical transfer function (OTF) of cone fiber optic bundle are presented, by analyzing of image transfer manner and digital simulating, a OTF test method with spotlight image analyzing is proposed and experiment results agree well with theoretic analyzing. OTF of cone fiber optic bundle can be obtained at a large frequency range (larger than 100 lp/mm), by rational setting of test system parameter.

Modulation transfer function is often used as a standard performance evaluation for optical components and imaging systems. The conventional test method for discrete optical element is the scanning knife –edge method. Because of the mosaic array architecture for taper and CCD, the integrated devices for CCD coupled with taper violate the isoplanatic conditions. The measured magnitudes of MTF vary with the position between edge and the array. In this paper, square-wave target MTF measurement was put forward. Square-wave targets with different spatial frequency were imaged by the integrated device, then transmit to the computer, the gray-scale value for the image of square-wave targets with certain spatial frequency could be got by the process program of image, so the CTF of the square-wave targets can be available, finally the MTF of the integrated device should got by the relationship between the CTF and MTF. The method avoids the influence of non-isoplanantic result from the dispersancy position between the ......

To use solid immersion lens is one of the practical methods to realize the near-field high-density optical data storage. But the storage system will work only on the condition that the distance between the bottom of the SIL and the surface of media is exactly controlled within the sub-wavelength scale. In this letter the flying height of the SIL is measured by the capacity between the SIL and the disc, and the SIL fixed in flying head is loaded on the surface of the rotating disc by flexible cantalever. The SIL will fly at different height with the different rotating speed of the disc. When it works, a computer is used to detect the flying height of the SIL, and after comparing this result with the preset value, it controls the disc to accelerate or decelerate, and this will result in adjusting the flying height of the SIL. In this way a certain height within the scale of 150~600 nm of the flying height over the disc surface is dynamically controlled when the disc is rotating in high speed.

The dependence of the resolution of a fluorescent confocal microscopy on fluorescent spectrum is studied, and the power transfer function and three-dimensional pulse spread function are derived. Assuming well-distributed fluorescent spectrum, calculated results show that the lateral resolution and the Axial resolution are worse while fluorescent spectrum widen and dispersion coefficient increased, compared with that by only using the central fluorescent wavelength. The detector responding to narrower fluorescent spectrum is good for the resolution.

A novel kind of Fourier transform spectral imager with high detecting sensitivity and stability is presented. This spectral imager is based on the Sagnac lateral shifting interferometer with one rotary reflecting mirror (therefore named ROSI). Because there is no entrance slit,the throughput is very high and therefore the sensitivity. The datacube of two dimensions of spatial information and spectral information can be obtained by starring mode. Some principle defects of the current high throughput(étendue) spectral imagers are overcomed.

The measurement for energy spectrum distribution and emittance of high-energy pulse electron beam in LIA injector is introduced simply in principle. Two parameters of 100ns pulse electron beam are measured and Cerenkov radiation images with 1ns resolution are obtained with image converter streak camera.

A project of acquisition and tracking of free space laser beam is advanced.And its major function is realized in laboratory.Analyses of precision of location and responsibility is given out.The results present positioning time of beacon is less than 25 ms and the relative error of position precision is less than 1.3%.This conclusion could be of some values for design of practical PAT subsystem on satellite.

By adding Polarization Maintaining Fiber on output terminal of SLD and Loyt depolarizer behind polarizer , the Degree of polarity can be reduced to 10 -3 ,and influence of outside conditions to light-wave′ state of polarization can be reduced too. And by calculating with Jones matrix,the relationship between four joint angles and polarization was discussed, and range of four joint angles was limited. In the end, how to link the fiber-optic and measure the joint angles was discussed.

The double random phase real-value encryption and decryption method is proposed for the optical image security system.A phase-only image to be encrypted together with a random phase mask in space plane is Fourier transformed .Then it attached anther random phase mask in Fourier plane is enlarged and reverse-Fourier transformed .Real part of the result is used as an encrypted image. The decryption of the real-value encrypted image can be carried out in the same means with encryption. That gives the exact original image. The method of encryption and decryption is simply performed and encrypted image is real-valued,so it is convenient for output.

A novel fast algorithm of composition FFT for correlation processing in SAR imaging and its optimum scheme is presented.By choosing the number of padding zeros and decomposition scheme,the algorithm′s parameters are optimized,and the computational volume of FFT in correlation processing can be significantly lowered down.The speed performance and applicability of the algorithm is given in detail.It improves the speed and decreases the processing delay of real time SAR imaging on a parallel processor.