A comprehensive and accurate numerical model is presented based on basic coupled equations to describe multi-Stokes Raman lasing performances in optical fibers. Though much work has been done on this,there are insufficiencies and shortcomings more or less in the literatures after analysis of them. These insufficiencies are also pointed out in this paper. The interactions between forward and backward traveling waves together with interactions between Stokes at different orders are all taken into account in this model. Effective core area for the interaction between multi-Stokes has also been obtained. The numerical solution of the differential system will lead in a natural way to calculate Stokes powers at the output end of the fiber. The proposed model is important for the design of CW cascaded Raman fiber lasers.

The high-efficiency SRS in barium nitrate (Ba(NO3)2) crystal was obtained pumped by a Q-switched Nd∶YAG laser (532 nm) operated at 30 Hz. In the forward scattered direction,the first (563 nm),second (599 nm) and third (639 nm) Stokes pulses were presented,the radiation fields of which had cone structures with the scattered angles of 1.7°,3.5° and 5.0°,respectively. Furthermore,it was pointed out that the angular distribution of Stokes radiation was independent of the pump intensity in this work. The results show that the angular distributions of SRS in Ba (N03)2 crystals are mainly attributed to the phase matched process. The pulse widths of the pump,first,second and third Stokes pulses were measured to be 11.6 ns,9.8 ns,8.4 ns and 4.5 ns,respectively. This indicates that SRS in Ba(NO3)2 crystals can provide the possibility of effective pulse compression and increase of peak pulse intensity. With the pump intensity of about 15 0 W / cm2,the maximum conversion efficiencies of the first,second and third Stokes pulses were 2 3.5%,8.8% and 3.4%,respectively. Moreover,the saturation phenomenon of SRS efficiency was experimentally observed,which was due to the thermal loading in the Ba(N03)2 crystal.

A widely tunable ring cavity fiber laser using 1480 nm high power LDs as forward and backward pumping is discussed. It also takes the Bi-based Er-doped fiber as the gain media,and uses the rotating F-P tunable filter and two band-pass filters as the wavelength tuning device. The laser can cover 100 nm(1523～1623 nm) tuning range controlled by software. The output power is above 2 dBm. The 3 dB bandwidth is below 0.1 nm. The wavelength repetition precision is below 0.01 nm.

The experimental scheme for particle sizing by detecting the intensity of scattered light with a linear CCD instead of a concentric ring detector was build. The excitation was a compact all-solid-state green laser instead of the conventional He-Ne laser. A full Mie scattering theory was employed to describe the scattering process,through computer fitting of the measured data of scattered intensity vs scattering angle,diameters of the standard polystyrene spheres of 4.91 μm and 9.88 μm dimensions were successfully retrieved. The present apparatus is proven to be simple and effective for sizing particles of 0.7～44.0 μm in diameter.

The fluorescence fiber gratings are fabricated the structure of fiber Bragg gratings (shortly FBGs) on Hydrogen-loaded Erbium-doped fluorescence fibers. The properties of temperature and strain for λB and τ have been studied experimentally,the fitting equations for λB (T,ε) and τ(T,ε) are given. The results show,like plain FBGs,the Bragg wavelength of fluorescence fiber gratings have well properties in response to temperature and strain,the thermal and stress sensitivity is 11.1 pm/℃ and 1.19 pm/με. Moreover,the lifetime of fluorescence fiber gratings represent good linearity with temperature or strain changes,the thermal and stress sensitivity is 0.59 μs/℃ and 6.16 ns/με,respectively. Finally,the results also provide novel ways of solving the cross-talking problem or simultaneously measuring of temperature and strain.

Through manufacturing the square glass silk,ion exchange,and precision machining of the sample,the square GRIN lens was made successfully. Some of its characteristics were obtained by the test. For example,distortion of the center part is quite small,and the image formation performs well etc. The success of the research indicates an direction for making square GRIN lens array and gaining its high fill-factor.

Based on two sides milling and polishing elements,a suit of Grin lens assistant jig design was brought forward. From technics characteristic and practice aspect,assistant jigs were analysed and proved. By times without number batch machining,this suit of assistant jig can achieve demand of Grin lens high efficiency batch make technology. Comparisons indicate that whole product line technics turns easy,procedure time in production are shortened and cost in assistant material are reduced. This research results showed that two sides milling and polishing means is a new useful and practical way.

In this paper,the copper slice packaging technique for FBG sensor was developed in consideration of bare optical fiber being fragility,and then the strain and temperature characteristics of the packaged FBG sensor were experimentally and theoretically studied. Compared with the experimental results of the bare FBG,the strain sensing property of the FBG sensor packaged by the copper slice is nearly the same as that of the bare FBG,however the temperature sensing ability of the packaged FBG sensor is improved and the temperature sensitivity coefficient is 2.78 times as much as that of the bare FBG. The strain and temperature resolution of the packaged FBG sensor are 1με and 0.03℃. The packaged FBG sensors can be used easily in engineering.

A method to eliminating the stress delay from fiber grating pressure sensors by means of dual fiber grating is proposed. The tuning for Bragg wavelength disparity of the dual grating can be realized in the case of the effect of external pressure by a method that symmetrically adheres two FBGs with the same wavelength respectively to the upper and down surfaces of the cantilever beam and links them up in series.The result of the research shows that the technology can eliminate the stress delay of the fiber-grating pressure sensor caused by the elastic material of the devices,and improve the linear response characteristic and repeatability. Under the condition of the pressure range of 0～40 MPa,the tuning range of the system dual-peak wavelength disparity is 5.12 nm (two times of the range of single-peak wavelength tuning) and the sensitivity of dual-peak wavelength disparity in pressure tuning can reach the high degree of 0.128 nm/MPa (also two times of the single-peak one.

Aiming to the idea of that “the Faraday effect will be doubled and the linear birefringence will be eliminated by using a return-back optical path”,the equivalent matrices of Orthoconjugate Reflection (OCR)-typed,Direct Reflection (DR)-typed,and Roof-prism Reflection (RPR)-typed optical current sensor models are derived,respectively. The results show that the OCR-typed return-back optical path can eliminate the effects of the linear birefringence,while the DR-typed and the RPR-typed return-back optical paths can not do that when the Faraday rotation is zero;all of these three return-back optical paths can not eliminate the effects of the linear birefringence when the Faraday rotation is not zero. Therefore,it is worthy to discuss that whether the view of “the Faraday effect will be doubled and the linear birefringence will be eliminated by using a return-back optical path” is correct for the bulk glass optical current sensór employing the conventional“-/+”signal processing scheme.

An coiled optical fiber sensor based on Sagnac interferometer for the measurement of ultrasonic wave propagated on the surface of a solid plate has been proposed and demonstrated. The advantage of this kind sensor is that the feeble vibration produced by ultrasonic wave on the surface of solid plate transmission can be detected accurately. The output optical intensity of interferometer is modulated when the ultrasonic wave signal passes through the sensing coil of the Sagnac interferometer. The amplitude and the frequency of ultrasonic signal are obtained by using Fourier transform technique. Phase-modulation property of optical fiber sensor is discussed and experiment results are also analyzed,which shows that the system could be used to detect the ultrasonic frequency characteristics on the surface of the solid plate transmission.

SERS effect of argentine is calculated and analyzed by use of Antenna Resonance Model. The results show that a maximum enhanced factor is greater than 140 at 1.38eV near infrared,factors are about 60,48 and 45 at 3.35 eV,3.90 eV and 4.30 eV near ultraviolet zone. It is predicted that a maximum enhanced factor is 70 in visible light zone. SERS spectrum of adenine and uracil are got from argentine piece treated by ORC. Adenine has distinct SERS effect with the presence of fluorescence. Four specific peak values are of SERS spectrum of uracil which has a maximum model,SERS ring breathing model,of four,at 1035 cm-1 affording the foundation.

Using the combination of Gaussian monocycles pulse with different amplitude and different delay,a new ultra-wideband (UWB) pulse design algorithm for Inband (narrowband or wideband) interference suppression is presented. With a Wireless Personal Area Network(WPAN) Communications short duration and a simple implement,the obtained UWB pulse not only meet Federal Communications Commission (FCC) spectral mask,but dramatically suppress the mutual interferences and successfully solves the coexistence problem between UWB system and others existing communication system. Compare with other pulse shapes,our pulse can carry more energy. In the end,the communication performance of the UWB pulse in the paper and the optimal Gaussian-based monocycle is compared,our pulse have an obvious advantage over the optimal Gaussian-based monocycle.

The in-situ chemical preparation technology has been explored for the first time for large size high polarization polymer photonic crystal fibers (pPCFs) preforms. The optimal polymerization conditions have been investigated. From experiments of the secondary draw-stretching of the preforms and the measured results such as microstructure,transmittance,glass transition temperature (Tg),molecular weight and so on,it is found that these preforms have a lot of characteristics,i. e. steady mechanics structure,higher optical transparency,and the pPCFs made by these preforms have ideally microstructure retaining,less holes collapse-rate,and lower non-intrinsic loss. If laser dyes and rare earth chelates were mixed into reaction system,the high polarization pPCFs preforms with fluorescence can be gained,which will be a new materials for development of the polarization maintaining PCF lasers.

The strain measurement by the fiber Bragg grating (FBG) is achieved by the Bragg wavelength change when the FBG receives axial strain. But,because of the transverse effect,the FBG' s position of installation will affect the result of the measurement,and the error of the installation will bring the error of the measurement. This paper receives the formula of the error which comes from the error of the installation through theoretical analysis. When the angle has existed in the axial of the optic fibre and installation positions needed,the greater the angle is,the greater the error is. The accuracy of installing position of optic fibre is very important,it concerns directly the accuracy of the measurement's result.

To overcome the high pump power of Raman amplification the remotely pumped erbium doped fiber amplifiers (RP-EDFA) are introduced in ultra-long haul dense wavelength division multiplexing (DWDM) systems. Firstly,the noise performance of a simple co-fiber RP-EDFA is investigated experimentally and theoretically,then the design method is discussed. The OSNRs and nonlinear phase shifts of typical systems based on RP-EDFA and backward pumped Raman amplification are compared theoretically,showing that RP-EDFA can efficiently reduce pump power and is appropriate for the ultralong span application. Finally,Q value of the typical transmission system is simulated. The results show that using RP-EDFA pumped by only 220 mW,1000 km transmission of a 40×11.6Gbit/s system with a span distance of 167 km can be achieved,with 4.4 dB margin of Q value.

A new type of polymer optical fiber connector based on the upside-down tapered lens (UDTL) technique was proposed. To increase the numerical aperture of polymer fiber and reduce the requirement of fiber ends to registration precision,the fiber end of the connector was created into an upside-down taper lens. The optical characteristics of the connector have been tested. Over 75 percent of coupling efficiency between the light source and the UDTL fiber end is in the range of 5.4 dB to 6.0 dB. More than 70 percent of connecting losses are in the 2.1 dB～2.7 dB range. The insertion losses are in the range from 2.2 dB to2.58 dB as the same suite of optical fiber jumper was inserted and drawn 200 times. The measured dates show that the performance of UDTL polymer fiber connector can meet the demand of fiber to the home.

Cross-phase modulational instability created by two beams of lights in the region of minimum group-velocity dispersion is investigated based on extended nonlinear Schrdinger equation with the fiber loss and high-order dispersion considered. The dispersion equation which describes the cross-phase modulational instability is obtained,and the numerical simulation is done. It is shown that because of the fourth-order dispersion,cross-phase modulational instability occurs at two spectrum regions in both anomalous and normal dispersion regimes of fiber. When second-order dispersion approaches the minimum value at the so-called zero dispersion wavelength,fourth-order dispersion dominates the cross-phase modulational instability and makes a new crest in the gain spectrum. Research also shows that fiber loss reduces the frequency range of the gain spectrum. For a given dispreading distance,the widths of the two spectrum regions increase until overlay when second-order dispersion approaches zero. When two beams of lights have difference,the cross-phase modulational instability is analyzed numerically.

The longest queue first scheduled assembly (LQF-SA) mechanism was proposed,where burst assembly and burst scheduling for optical burst-switching networks were integrated. The proposed mechanism,ingress edge nodes have been multipled assembly queues where IP packets were stored according to their egresses and QoS classes. Among these queues,the longest one was scheduled to assemble bursts by a scheduler at a fixed interval. In real networks,traffic usually distributed nonuniformly and there existed heavier traffic between some source and destination pairs. Simulation results show that LQF-SA could adapt well to the non-uniform traffic profiles. Furthermore,even under uniform traffic,LQF-SA is also super to round-robin scheduled assembly (RR-SA) in terms of burst size distribution,assembly efficiency and burst loss rate.

The deflection expressions,based on the vector refraction theorem,are derived from the light beam deflection through a pair of orthogonal prisms,and the main design parameters of the device are confirmed. The main error items are especially analyzed by the method of numerical simulation,and the total error and the actual precision index is also presented. The result shows the light beam,with the deflection precision of less than 0.8μrad,can be deflected 500μrad in both the horizontal and the vertical field angle,the deflection precision of which is mostly influenced by the random errors. The total error converted on the rotation angle of prism is 1 2.7 2 arcsec,which causes the deflection error of light beam 0.365μrad,greater than the reading resolution of system 0.0387μrad and less than the precision index of light beam deflection 0.8μrad,so the design is rational and feasible.

A theoretical model to analyze the beam smoothing performance,realized by the diffractive optical element (DOE) and the smoothing by spectral dispersion (SSD) technique,is setup based on the spatial frequency spectra analysis method. Utilizing this theoretical model,the parameters,including the integration time,the modulation frequency,the phase modulation coefficient and the linear dispersion of the diffraction grating,of the SSD technique can be optimized to improve the beam smoothing performance. The influences of the parameters of the SSD technique on the beam smoothing performance are numerically analyzed. Furthermore,the simulated results show that the phase distortion should be changed during the integration time in order to obtain a good beam smoothing performance.

A new compression method of interferogram hyperspectral images based on ROI (Region of Interest) coding is proposed,which is based on the analyses of the characteristics of hyperspectral imaging spectrometry. This method that uses the symmetry of the interfering stripes,processes the intra-frame compression and integrates the rectangle ROI coding improves compression ratio of remote sensing images and reaches the requirements of near-lossless compression. Experimental results showed that when relative spectral quadratic error was 2.04% the compression radio reached 9.66∶1.

The characteristic of the gray-tone pattern generated by DMD is discussed and an imaging model for describing the digital gray-tone lithography process is developed. In addition,the effects of DMD operation mode and the parameters of imaging system to the distribution of the exposure dose on the photoresist are simulated and discussed. The model will be helpful for the experimental research on the digital lithography.

According to the Mie scattering theory,the backward light scattering power of air bubble appears as clear enhancement near 180° in the condition that the air bubbles are not relevant to each other.The experiment was done with the simulative ship wake. The attenuation characteristic of air bubbles' backward scattered light power was studied with 632.8 nm laser illumination in two conditions-slim beam illumination and expanded beam illumination. The experiment results indicate that considering the attenuation of light intensity as backward scattered light propagating in the water,expanded beam illumination has advantage when air bubbles is nearer and slim beam illumination is adapt to detect farther bubbles.

A spacial transient optical signal location system based on optical location method is designed. This system cooperates with energy detection system. After energy detection system detects the target signal,the location system gets the target image and stores the coordinates of target pixels. Then DSP calculates the centroid of target signal and sends the results to lower computer. The composition of system,the design method of modules,and the test results are given in this paper. Experiments show that this location system is accurate and feasible.

An adaptive output window technique based on gray redundancy for infrared image is proposed in order to overcome the disadvantage of infrared image gray distribution. The adaptive output window threshold is calculated from the histogram,if the pixels sum of the same gray level is zero,this gray level is compressed. Those gray levels which pixel sum is less than the threshold are replaced by gray level of the threshold. Then effective gray-levels are distributed equidistantly. This algorithm can eliminate gray redundance and no gray-level lost. The results show that the image quality has been improved. Theis algorithm achieved real-time processing.

Aimed at the ubiquitous problem of losing frame in the course of video image real-time storing,the typical storage arithmetic has been analyzed thoroughly in this paper. Then,the cause of losing video image in the process of real-time storing was found. When the same size files were saved continuously to the disk of the computer,the storage rate was fluctuant in stated range. Through adopting the queue buffer structure,the influence of the storage rate fluctuating was avoided effectively;consequently the real-time storage of high-speed video image was ensured in the condition that the rate of data flow is less than the mean rate of storage. Finally the problem of losing frame was solved. By experiment,the feasibility and reliability of the arithmetic was proved.

The optical characteristics of aerosol over Naqu and the suburb of Beijing in combination with Micro Pulse Lidar(MPL) were measured and analyzed. The vertical distribution of aerosol extinction coefficients over the Naqu was showed in comparison with the results over the suburb of Beijing and the heights of Planetary Boundary Layer of Naqu are discussed. The results indicates that the components and concentration of aerosol are more uneven in Beijing than in Naqu,and the quality of air is better in Naqu than in Beijing. Consequently,MPL is a useful tool for monitoring aerosol in atmosphere.

A new type of multi-slit streak tube was designed with large efficient area,smaller bulk and lighter weight. By programming and Monte-Carlo simulation,even 10 mm off the axis,the spatial resolution can reach to 20 lp/mm,and the static physical temporal resolution can reach to 100 ps. On the basic of theoretical design,some processes were made such as the structural design,machining and assembly. A MS-Streak tube was manufactured. Its efficient photocathode area can reach ф22 mm. After testing with static experiment system set up,a static image with certain spatial resolution was obtained.

Based on the injected carrier transportation mechanisms in multiple quantum wells (MQW),non-uniform distribution of injected carriers in MQW was computed numerically. And several parameters,which significantly affect the carrier non-uniform distribution in MQW,were investigated. Results show that with the increase of the number of quantum wells,injected current and quantum barrier height increases the non-uniformity of carrier distribution in MQW,but with the decrease of working temperature it will also decrease.

The digital image has distortion because the inherent characteristic of imaging optical system in measuring body's scale through high precision measurement system based on the CCD camera was used as a core component. The distortion model of 3th polynomial was found based on primary aberration theory. The scale rebuild was progressed after analyzing and validating the excellence and defect of different interpolation method. The image' s noise contrapose one of correction methods filter off. The correction image is approve of fitting high precision imaging measurement through experimentation.

Photonic quantum-well (QW) structures can be constructed by stacking 3 photonic crystals (PCs) with the same photonic band gap and different defect modes. On condition that the defect mode of the PC in the well region is located into nontransmission frequency ranges of the PCs in the barrier regions,the confined photonic state appears and can completely transmit through the structure by tunneling. However,its transmission will be strongly prohibited due to vanishing of the photonic QW induced by shifting the defect mode frequency of either of the PCs in the surrounded regions to that of the middle PC. Switching and narrow band filtering can be realized simultaneously with the structure. The theoretical calculation has been carried out by transfer matrix methods.

Unique optical properties of the simple lens composed of left-handed material (LHM) are reasonedly studied here according to Geometrical Optics. Analytic calculation of the negative refraction at the spherical surface is conducted demonstrating that the usual optical formulas still hold true for the LHM lens. The inherent merits of the LHM lenses are discussed comparing to their counterparts made of right-handed material (RHM). Finally,single thin LHM lens with a complete correction of spherical aberration is verified and a practical example is presented accordingly.

The modulation of photon polarization by liquid crystal variable retarder (LCVR) whose phase retardation can be controlled easily by its driving voltage is described. A spinning polarimeter is designed to calibrate the LCVR for 820nm wavelength in situ. The driving voltages corresponding to 1/4λ,3/4λ,1/ 2λ and 1λ of LCVR are obtained,and the polarization of photon is modulated by changing the driving voltage via a computer. The theoretical analysis and experimental result are presented. The advantages of the proposed method are insensitivity to the incident photon direction,large wavelength range without mechanical movement,and real-time control.

Based on interference principle of equal inclination. The distribution of intensity,visibility and fringes were analysed theoretically,and the influence of incidence angle on the distribution of intensity and visibility and of phase angle on the distribution of fringes by medium film reflection for a Gaussian beam discussed. Numerical calculation results show,on a plane vertical to the direction of light propagation,it is a circular spot for reflected light in the region of super-position. With the increase of incidence angle,the visibility reduced gradually,the reflected intensity deviated from Gaussian distribution,the size of beam spot broadened,the peak value reduced. The distribution of fringes by medium film reflection for a Gaussian beam in space is similar to that of a plane light,which is mainly decided by incidence angle and thickness of medium film.

Based on the Rayleigh-Sommerfeld diffraction integral,the far-field expression for ultrashort pulsed Gaussian beams with constant waist width in a linear dispersive medium is derived without involving the paraxial approximation,and used to study their far-field properties. The expression is applicable to the large diffraction angle. It is found that there exists a critical diffraction angle θc,for the power spectrum of pulsed Gaussian beams with constant waist width. The spectrum is blue-shifted if θc,whereas,for θ>θc,the spectrum is red-shifted,and the redshift increases with increasing θ. Additionally,there is a time shift,which increases with an increase of θ,and the Gaussian pulse form can not remain unchanged in the far field. Finally,the group velocity dispersion results in the chirp,which increases with decreasing diffraction angle.

Based on the propagation theory of partially coherent light,the spectral shift and spectral switch of partially coherent modified Bessel-Gauss beams passing through an aperture lens are studied. Numerical results show that the spectral shift and spectral switch of partially coherent modified Bessel-Gauss beams are dependent upon the spectral degree of coherence,Fresnel number and truncation parameter. The number of spectral switch increases with increasing Fresnel number and truncation parameter,but decreases with increasing spectral degree of coherence. When the truncation parameter is larger than a certain value,the spectral switch disappears. For example,when the spectral degree of coherence equals to 0.5,and the truncation parameter is larger than 2.2,the spectral switch disappears and there is only the blue shift.