Supercontinuum with a spectral bandwidth of 700 nm (1.09μm ～ 1.79μm) was achieved in a 1.8-m-long photonic crystal fiber with an average core radius of 2.0 μm pumped by optical femtosecond pulses at the wavelength of 1. 2759 μm, with the average power of 30 mW, the duration of 250 fs and the repetition rate of 250 kHz from an optical parametric amplifier. It was interpreted that the spectral broadening was due to the fission of higher-order solitons and four-wave mixing. The concave profile at the wavelength of about 1.4 μm was resulted from the OH absorption. The broadened spectra were applicable to a multi channel optical source with ultra-short pulsewidth for WDM communication and photonic network systems.

Two kinds of fiber loops are employed as cavity mirrors to setup a linear cavity tunable multi-wavelength Er-doped fiber laser. By cooling Er-doped fiber in liquid nitrogen to 77 K, employing the tunable fiber loop mirror as a output mirror,and utilizing the filter characteristic of Mach-Zehnder interferometer and the wide-band tunable reflectance feature of the tunable fiber loop mirror together, a multi-wavelength fiber laser with channel spacing of ~0.4 nm are got. A maximum number 48 of output lasing wavelengths is achieved, and the lasing multi-wavelength region can be conveniently tuned from 1525nm to 1555nm.

The frequency of an external-cavity diode laser has been stabilized to absorption line of methane at wavelengths around 1.6 μm by employing the wavelength modulation technique and the digitized controller. The frequency fluctuation of the stabilized laser is held within 5.6 MHz and better than 160 MHz of the free-running laser. The root of Allan variance of error signals reaches a minimum of 1.66×10 -11 when averaging time is 64 s, well within the precision needed for application. And various limiting factors are analyzed. It is found that the stability is mostly limited by the noise of photodetector and frequency modulation in the experiment. Several methods of improved stability are also presented here. Such a treatment can provide a guidance of any experiment of frequency stabilization. The primary application of this stabilized laser is to provide a frequency reference for remote sensing of the concentration of methane.

A tunable linear cavity Er/Yb co-doped double-clad fiber laser operating in L-band, which utilizes amplified spontaneous emission (ASE) as a secondary pump source, is presented. The output wavelength can be tuned over 34 nm with power excursion of 0.4 dB by using a high birefringence fiber loop mirror as a wavelength filter. With 5 LDs side-pumping Er/Yb co-doped fiber simultaneously, an output power of 200 mW is achieved and the stability of output laser is very good.

The 14xxnm AlGaInAs/AlInAs/InP Strained Quantum Well Lasers with Tapered Gain Regions and with Ridge Waveguide is fabricated under the same experimental condition. The laser structure is grown by MOCVD. The output power and the saturation current of the former structure is higher than the latter under the same driving current when the cavity length is 800 μm. When the cavity length is 1200 μm the output power above 500 mW and the saturation current above 3 A have been achieved for the former structure. The measured vertical and parallel divergence angle are 39° and 11°, respectively.

A preset grating technique was put forward for slowly response characteristic of photorefractive crystal. This technique can be achieved by preset laser source independent with signal beam. The characteristic and physical mechanism of SPPC based on preset grating were studied experimentally. It indicated that response time of photorefractive SPPC can be deduced greatly and has great practical value for the low repeat, narrow pulse beam.

The electrical resistance of the fused interface is simply characterized using a resistive layer, and the voltage distribution inside the vertical-cavity surface-emitting lasers(VCSELs) are calculated by using a method of finding self-consistent solutions for the Poisson′s, injected current density, carrier diffusion, and voltage drop equations, and the temperature distribution inside the VCSELs are obtained subsequently by solving the thermal conduction equation. The influences of the electrical resistance of the fused interface on the distribution of voltage and temperature inside the single-fused VCSELs and the radial distribution of the injected current density, carrier density, voltage drop and temperature in the active layer are analyzed in detail.

For tetra-lateral position sensitive detectors (PSD), the calculated positions obtained with the conventional equations of position calculation do not correspond to the real spot positions., and have serious pincushion distortion. A modified equation is proposed in terms of the analytical solutions of Lucovsky equation. According to the results, the correction of the PSD can be easily achieved and the linearity can also be greatly improved in most of the central active area by the modified equation. In the 60% of the active area of 1×1 cm 2 PSD, the position root mean square (rms) error was less than 3 μm , the position non-linearity was less than 0.05%. This modified equation can be fit for all tetra-lateral PSDs.

The structure and the properties of the holographic polymer dispersed liquid crystal (H-PDLC) grating were explored and analyzed both theoretically and experimentally. The results of the experiment are consistent with those of the theory. Coupled-wave theory is used to analyze and explain the properties of the grating. The grating was used to flatten the gain of EDFAs and dynamic gain equalization can be implemented with the electrically controlled gratings. The gain from 1530 nm to 1560 nm can be flattened with the fluctuation of the amplified spontaneous emission decreased from 3.3 dB to less than 0.2 dB_ p-p in the temperature range 0-65℃.

An analysis about the wavelength-division multiplexing isolation filter using concatenated long period chirped fiber grating by transmission matrix method is given. The key factors of design high performance of such type filter are proposed. The simulation result demonstrates that such type isolation filter have a very large band width, equal frequency spacing, high isolation, and with a neglect dispersion in the band pass, and the frequency spacing can be tuned by tuning the fiber length between the concatenated long period chirped fiber gratings.

The state of polarization plays an important role in twisted nematic liquid crystal displays. Combined with Jones matrix and j-circle method based on Stokes vectors, a novel method is proposed for the optimization of reflective twisted nematic liquid crystal displays. The difference between the space parameters method and the present method is that by chasing the polarization state in propagation the optimum condition is obtained. The proposed method has the advantage of ease to understand and can simultaneously optimize several parameters. The new optimal displays modes are found.

An equivalent single layer model, as well as one-dimensional spring-mass-capacitor model, has been built up, to simplify the electrostatic analysis of multiple-layer fixed-fixed beam of 1.55 μm Si-based MOEMS tunable optical filters. The effects of the structure parameters of the beams, the electrode geometry and initial air gap to the tuning coefficient, have been analyzed. The tuning characteristics have been simulated quantitatively with the classical mechanical theory and transfer matrix methods. The simulations fit in well with the experimental results.

The coupling between fiber optical taper and CCD is the critical technique for the integrated taper assembly image intensified sensors. Compared to a lens-coupled CCD camera system, the CCD camera coupled with fiber optical taper has higher collection efficiency, and yields significant gains. So fiber optical taper plays an important role in the integrated devices. The coupling efficient between fiber optical taper and CCD exerts an influence on the signal-to-noise ratio of the integrated devices, but the effective transmission of taper has influence upon the coupling efficient. In this paper, the core-packing fraction of taper has been calculated precisely according to the virtual structure of fiber optical element, the attenuation and losses of the light energy transmitted through fiber taper have also been analyzed and deduced according to the ray mode transmission characteristics in the taper. Finally the effective transmission of taper was deduced, and an objective measurement of the effective transmi

Based on the principle of prism coupling and improved inverse WKB theory, the refractive-index profiles of planar waveguides were measured. The refractive-index curves of ion exchange glass waveguides were obtained by this way. The method has advantages on convenient operation and accurate results.

Based on time-domain beam propagation methods (TD-BPM) with the slowly varying envelope approximation (SVEA), both schemes of generalized Douglas(GD)and conventional central-difference(CN)have been respectively used to disperse lightwave transmission equation, and have been compared each other. The results showed that the former is more accurate. The explicit and implicit expressions of absorbing and transparent boundary condition have been derived for the GD scheme in TD-BPM, respectively. The boundary condition based on the alternating-direction implicit method(ADIM)was also established. Meanwhile, incident wave and connecting condition have been discussed in details. As a result, the boundary condition of implicit GD-TD-BPM must apply implicit expression, and settling incident wave in computational region may effectively detail the reflected field.

The forward light scattering of the human′s static and deformed erythrocytes in Couette flow is analyzed by the theory of anomalous diffraction. The erythrocytes′ process of light scattering is simulated by Monte Carlo method based on the equal-volume or equal-surface model , the values of length in all three axes are worked out and the results are analyzed carefully. The result shows that compared with fraunhofer diffraction, this new kind of analysis is more accurate in precision.

The relationship of polarizability and scattering number has great value to extract the backscattering light deeply into the tissue. The relationship of polarizability of transmitted light and the scattering number of light in medium is analyzed. The scattering number that purely depolarization needed is given. And the result is validated by directly scattering experiment. The conclusion can be made that when the scattering number is 14, the polarization light will be depolarized.

The variation rule of chromatic dispersion induced phase error of the beam former based on dispersion devices is studied using an intensity-frequency modulated model. Based on the phase error, the maximum dispersion limitation is presented when the phase precision is 0.5 ps. It is also shown that there exists an optimal frequency modulation index that makes the system dispersion tolerance maximum. When the intensity modulation index increases, the optimal frequency modulation index increases.

A nonlinear optical loop mirror constructed from dispersion-decreasing fiber is proposed for simultaneous compression and pedestal suppression of higher-order soliton. Numerical simulation indicates that with the different soliton order, we can use the different fiber length for optimum compression. It is found that the higher of the soliton order, the shorter of the fiber length for optimal compression, with the greater peak intensity and the lower energy transmissivity. Our research results also show that the power-splitting ratio of the loop for optimal compression can be obtained, under this condition, the peak intensity and energy transmissivity of the pulse compressed is greater, and the pedestal is efficiently suppressed.

A scheme for all-optical OR gate is proposed based on teraherz optical asymmetric demultiplexer (TOAD). The feasibility of this scheme is theoretically analyzed with the principle of TOAD. Based on this, all-optical OR gate operation at 10 Gb/s is successfully demonstrated. Two data signals coded 1100 and 0110 are used in the experiment, giving chance to demonstrate all of the possibilities of OR gate operation. The successful demonstration of such kinds of codes also shows the potential of this scheme to process OR gate operation on data with arbitrary codes or data of pseudo-random bit streams (PRBS). For the influence of the gain recovery time of SOA, optimising method is proposed. Analysis shows that with this scheme, ultrafast and high extinction ratio OR gate operation can be performed.

The experiments of the adaptive compensation up to Second-Order in 40 Gbit/ s OTDM System based on degree of polarization (DOP) feedback control are reported. Around the operation wavelength 1560.5 nm of laser source, the DGD and the Second Order PMD decreased obviously after compensation. The effectiveness of the PMD compensator was confirmed by the comparison of eye diagrams, PMD measurement and BER analyses before and after compensation. The particle swarm optimization (PSO) was employed as control algorithm in the Adaptive PMD Compensation system. The compensation time was 30 ms.

The performance of normalized throughput in a hybrid WDMA-OCDMA system is studied. The effect of optical beat noise on the normalized throughput is analyzed. The scheme of BCH channel coding is proposed to improve the performance of a hybrid WDMA-OCDMA system.The analysis result shows that the normalized throughput is a little decreased when traffic load is light, but can improved greatly when traffic load is medium and heavy. Furthermore, the maximum normalized throughput will increase for the BCH-coded hybrid WDMA-OCDMA system.

A theoretical analysis is given about the relationship between clock frequency components and pulse amplitude for unequal-amplitude even-multiplexed OTDM (Optical Time Division Multiplexing) signals, and physical mechanism of clock recovery based on SOA (Semiconductor Optical Amplifier) mode-locked fiber laser is demonstrated from the point of time domain and frequency domain respectively. In experiment, 2.5 GHz frame clock and 20 GHz bit clock are extracted from unequal-amplitude even-multiplexed 8×2.5 GHz signals by using SOA mode-locked fiber laser. 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.

On the basis of analyzing the design theory of infrared imaging spectrometer based on binary optical element (BOE), in order to eliminate the limitation, which the focal length vary with incidence wavelength in infrared optical system with binary optical component as transparent imaging element, the hybrid refraction/diffraction zoom optical system combining the off-axial three-mirror reflective system is introduced. Furthermore, arming at the principle of infrared hot detection of military objects, the concretely design example of infrared imaging spectrometer was given. The design results show that The system possesses simple structure, high acceptance of light energy, long back-working distance, and better aberration correction. In addition, the system has lower requirements for materials and higher detection precision to infrared focal plane of the stare array detector.

The erasing properties of amorphous Ge_2Sb_2Te_5 phase change films are studied by using blue-green laser. Blue-green lasers with 1000ns, 500ns, 100ns, and 60ns pulse duration are selected in the experiment. The results show that reflectivity contrast increases with the laser power increases. Within the time with 1000ns,500ns,100ns,60ns range, the amorphous films change to the crystalline phase. Erasing power higher than 4.49mW, the reflectivity contrast of films irradiation upon blue-green laser with 60ns is higher than 15%, which indicates Ge_2Sb_2Te_5 films have the high crystallization speed under the condition of short pulse duration and low erasing power. And also the optical spectra properties between amorphous and crystalline phases are analyzed. Compare to the reflectivity and the reflectivity contrast of amorphous and crystalline phases films at different wavelength with 780nm,650nm,514nm and 405nm, and present the future improving way to Ge_2Sb_2Te_5 films applied in the blue –ray disc.

The finite difference time domain (FDTD) method is used to simulate light propagating from vacuum to glass material covered with nano-porous films, and the transmittance spectrum with different wavelength are obtained. Compared with theoretical spectrum, the refractive index of the nano-porous film is calculated. A series of nano-porous films with the porous ratio of 5%、10%、15%、20% as well as 30% are simulated. In the end of this paper, a broad-band antireflection coating composed of the nano-porous film and one MgF2 layer is proposed. Simulated this antireflection coating by FDTD method, the average transmittance can be reached above 99.5% between 400nm and 800nm.

An accurate method for measuring the refractive index and thickness of a dielectric film in a leakage waveguide is presented in details. The dispersion equation of a four-layers structure is derived. The complex propagation constant is determined with the Newton-Raphson numerical method. With the dispersion equation derived above , the method for measuring the optical parameters of the single-layer is presented. As an example, the refractive index and thickness of the single-layer silica film deposited with Plasma Enhanced Chemical Vapor Deposition are determined by the present method. The result shows that the present method is accurate and fast compared with the traditional method .To determine the parameters of a sample, a personal computer only spends 60ms using the present method.

Nanocrystalline ZnO films is a promising material for short-wave laser and luminescence etc, due to its wide band gap (3.37 eV) and high exciton binding energy(60 meV)at room temperature.Nanocrystalline ZnO films is prepared by using sol-gel, grow on a quartz glass subtractes, Photoluminescence spectra and Absorption spectra of nanocrystalline ZnO films with excitation wavelength 365 nm are measured at room temperature.Two emission bands are observed, one being a narrow violet band its central wavelength is 395nm and the other being wide visible band its central wavelength is 524 nm, 450 nm.Crystal structure of samples are examined by X-ray diffraction (XRD) pattern, the mean grain size of nanocrystalline ZnO films are calculated by with Debye-Scherrer formula.The results indicate that nanocrystalline ZnO films has a hexagonal wurtzite structure and polycrystalline, and showed sharp diffraction peak for ZnO(002),which indicate that as-sputered film were highly c-axis oriented.In particular the mechanism behind......

A new compression scheme of satellite interferential superspectral images is proposed based on the analyses of satellite superspectral images. There are two novelties in the scheme: the first is that the compression coding is an image sequence compression method with low memory, which utilizes the matching algorithm in the wavelet domain to remove the redundancy between the two successive frames; The second is that in order to protect the information of the spectrum the scheme adopts a new ROI (Region Of Interest ) coding algorithm, in which the lifting procedure is carried out in code stream organization stage. As results, the low coding efficiency situation due to the nature of the bitplane shift methods could be improved, which enables the high fidelity in the background (BG) and makes better qualities of spectrum curve. The experimental results

BR-D96N is a genetic mutant of bacteriorhodopsin (BR) with obviously photochromic characteristic benefiting from the prolonged lifetime of the M state. According to the Kramers-Kronig relation the absorption spectrum change of a sample will cause the refractive index change. In this paper, the autors firstly measured the absorption spectra of the BR-D96N film before and after light irradiation. Then the refractive index change spectrum of the sample is calculated according to the Kramers-Kronig transformation. In order to directly measure the photoinduced refractive index change of the bacteriorhodopsin film, Michelson interferometer is used to measure the refractive index change at different wavelength. The experimentally measured values were compared with the theoretically calculated curve.

The dynamics characteristic of multilevel complex vibration reduction system was researched. The paper was based on the coordinate transformation of space general motion for rigid bodies and Lagrange equation of multilevel vibration reduction system. With multi-degrees of freedom of relative motion between mass blocks (including terrace) was carried out. The influence relationships between active force of the actuator and parameters of the vibroshock were analyzed. The results were as follows:When the actuator was installed between the vibration reduction object and the rigid bodies, multilevel complex vibration reduction system had good vibration reduction of intermediate frequency and high frequency domain or low frequency domain. The active control force of vibration reduction was not big, and it was very convenient to use in any advanced vibration reduction control.

In order to improve the recording speed and satisfy the requirement of shooting range, in this paper the bottleneck was found by analyzing the data channels of whole system; through studying the relation of file size and storage rate and adopting the technology of map file composing and segmentation, RAID 0,make the storage rate of disk improved and the data channels of system ameliorated. Finally the speed of the whole system has been improved, the integration and real-time requirement of recording data are ensured.

Holographic plate will suffer reciprocity law failure when exposed to low intensity or short pulse laser, a probabilistic model based on the Gurney-Mott hypothesis was constructed to study the reciprocity law of holographic plate ,the model yields reciprocity law failure curves with exposure time from 10-14 second to 102 second, and the curve changes with exposure energy is also discussed.

A method that imaged directly to sloping edge was used to get the modulation transfer function of fiber optic taper coupled with CCD. It used static edge that was tilted slightly with respect to the columns of fibre to achieve different value of different row. This method replaced scanning in conventional test and it was not necessary to ensure that edge was parallel strictly to array .Thus mechanical error was deduced accordingly. In data processing adopting two averages including different position of one image and multi-measurement result .This processing avoided the influence of non-isoplanantic result from dispersancy to a certain extent.

A digital hologram watermarking with a phase encryption feature is proposed based on a binary optical phase retrieval algorithm. The watermark has been encoded with the binary optical phase algorithm and encrypted with a binary phase key. Comparing to the digital hologram watermarking with binary phase structure under the plane illumination, the security of the proposed method is greatly improved by using a binary phase key while the quality of decrypted watermark with large information contents is almost maintained unchanged. The decrypting processing is independent of original host image. The quality of decrypting watermark under the different sizes of encryption keys has been discussed. The simulation results prove the theoretical analysis.

A novel method used for the enhancement of the accuracy of the measurement of the retardance of a quarter-wave plate employing two polaroids and a prism is reported under the condition of knowing the direction of the fast axis of the plate. The theoretical analysis of the principle and the uncertainty formula are given. An application example is also demonstrated. The measured result of the example is verified with an experiment. The main advantages of this method include the accuracy enhancement, simple measuring setup and easy operation.

The phase unwrapping is a very difficult problem for profilometry of object containing depth discontinuities .The problem can be resolved with dual-frequency measurement technique. Two measurements with dual different frequencies cannot be contented with real-time demand. The new profilometry is based on compound grating, generated by computer software, projected by liquid crystal projector, so that the grating with different precision is easily created, conveniently changed .The same purpose is attained as capturing two different frequencies′ deforming gratings. Two phase maps are determined simultaneously, whose sensitivity to height variations is correlated with the frequency of pattern gratings. The phase uncertainty of the finest grating can be revised by the phase information coming from the coarse one. Finally, satisfactory experimental results are demonstrated. Meanwhile, it is verified that the new method has high speed, accurate unwrapping and extensive measure range.

Basing on Young′s double-slit interference, the grating′s Talbot and fractional Talbot phenomena under illumination of parallel homochromatic wave were discussed. The grating diffraction fringes on the imaging plane results virtually from the so-called erasable coherent superposition of many Young′s interference fringes of double-slit with certain distance within the grating. Although the distance between fringes and the places of bright and dark fringe were not unvaried, there would be a shift of half period of the image versus the grating viz. fringe distribution versus scratches of grating. This shift would be determined by parity of parameter α of double-slit, namely that when α is even, the shift don′t appear, while α is odd, it appear.

The influence of temperature fluctuation upon focal length, harmonic wavelength and diffraction efficiency of harmonic diffractive lenses was analyzed, correspondingly, the mathematic formulas were constructed and some numerical simulations were carried out. The shifting function, which denoted the degrees of focal length and harmonic wavelength varied with temperature fluctuation, was developed. The disciplinarians of harmonic diffractive lenses’ diffraction efficiency varying with temperature were listed. In the end, the influence of temperature fluctuation on harmonic diffractive lenses with different phase-matching number and the same designed wavelength was compared. The result indicates that the diffractive lens with lager phase-matching number was more sensitive to temperature fluctuation.

The electromagnetic field in absorbing and dispersive dielectrics is quantized by the method of Green′s function, the quantum properties of light field in the plane interface system with the plasma / absorbing and dispersive dielectrics for one-dimension are investigated. The results show that the working states of the system are related closely with the frequency of light , and the damping of plasma have not only the effects evidently on the power spectrum of electric- field quantum fluctuations in myself region , also in other region.