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In this study, the nonlinear Schrodinger equation for pulse propagation in silicon-on-insulator waveguides is examined. The transmission characteristics of chirped Airy pulses in silicon-on-insulator waveguides are simulated using a split-step Fourier method. When the Airy pulse has an positive chirp, the degree of focusing is higher, the distance at which the initial Airy pulse reaches its focal point is decreased, and the distance between the focal points of the new and initial Airy pulses increases. The energy of the initial pulse at the focal point increases first and then decreases with the magnitude of the positive chirp. When the Airy pulse has an negative chirp, the degree of focusing is reduced, and the focal length is longer; the distance between the new and initial Airy pulse focal points is smaller. Regardless of whether chirp is positive or negative, the distance between the focal points of the initial and new Airy pulses increases with chirp. Increases of the truncation coefficient and initial input power cause a decrease in the degree of pulse focusing. The third-order dispersion changes the distance at which the initial Airy pulse focuses, changing also the distance between the focal points of the new and initial Airy pulses.

IA121 view of the traditional BP model in classification of speech characteristic signal, the model has low classification accuracy, poor stability, easy to fall into the local minimum, and so on, therefore, the adaptive genetic algorithm is introduced to the optimization of BP model parameters to overcome the problems of the model. The adaptive genetic algorithm has strong adaptability and robustness, so the genetic algorithm is used to optimize the weights and threshold parameters of the BP model, which can effectively improve the performance of the neural network. Establish the classification system of speech characteristic signal based on adaptive genetic neural network, using the folk song, guzheng, rock and pop four different music speech characteristic signal to train and test the classification model. The test results show that, compared with the traditional BP model, the classification model of speech characteristic signal based on adaptive genetic neural network has higher classification accuracy.

When using BP model to classify speech feature signal, the initial weight and threshold of BP model randomly causes the model to fall into local minimum. A differential evolution algorithm is proposed to optimize the weight and threshold parameters of BP model, then establishing a classification model of speech feature signal based on differential evolution BP neural network algorithm. The classification models are trained and tested using the speech feature signals of four different kinds of music, folk songs, zither, rock and pop music. The test results show that compared with the traditional BP model, the improved BP algorithm model, the speech feature signal classification model based on differential evolution BP neural network is better in operation stability and classification accuracy.

As one kind of organic photochromic optical storage material, fulgides are well-known for their thermally irreversibility. The two-photon absorption 3D optical storage technology is one of the hot research topics in the field of high-density information storage. Using optical image storage technology the recording and reading rates can be improved. In this paper, it’s found that in one kind of 3-indoly-benzylfulgimide/PMMA film, there exits two-photon absorption property. And depending on this property, the two-photon absorption photochromic optical image storage was realized in an indoly-benzylfulgimide/PMMA film. It is proved that the N-benzyl-1,3,4-trimethyl-2-(2-methyl-) indoly-fulgimide has potential application in the two-photon absorption 3D optical storage.

As one kind of organic photochromic optical storage material, fulgides are well-known for their thermally irreversibility. In this paper, two kinds of new fulgide materials, like pyrrylfulgide/PMMA film and 3-indoly-benzylfulgimide/PMMA film are used as storage materials. Different kinds of optical storage properties, like photosensitive spectral range, light sensitivity, resolution, fatigue resistance and thermal stability of them are measured. The experimental results show that for pyrrylfulgide and 3-indoly-benzylfulgimide, their photosensitive spectral range were 500nm~780nm and 480nm~720nm respectively; their maximum absorption were at 626nm and 573nm respectively; under 633nm light excitation, their light reaction constants of bleaching process on the exciting light polarization direction were 1.4×10-3cm2/mJ and 2.89×10-3cm2/mJ respectively; their resolution were both higher than 1680 lines/mm; they can be recycled more than 33 times and 70 times respectively; at room temperature they can be stored for 12 months and 14 months respectively. And it is concluded that pyrrylfulgide and 3-indoly-benzylfulgimide show better application potential in the field of rewriteable optical storage.

Magneto-Optical modulation technology has become key component in many optical information systems. However, due to the abstract theoretical knowledge, many textbooks do not introduce the properties of circular anisotropy, so it is difficult for most students to understand the polarization properties of light accurately and in depth. In this paper, the processes of Magneto-Optical modulation are Three-Dimensionally dynamically simulated by using MATLAB software first. These simulations make the complex and abstract light propagation processes become visual, which are effective aids for optics’ teaching. These simulations can enhance the understanding of the concept and the interactions with media of polarized lights and the principles of Magneto-Optical modulation. Second, a magnetic rotation glass is used to produce Magneto-Optical modulator, and finally the optical communication simulation experiment is realized and the effect is good. Experimental results show that the magneto-optical modulator has advantages like low power requirements, low modulation voltage, simple device, flexible, long life-time and small affect to the external temperature etc.

In order to overcome the problems such as poor global search ability, slow convergence rate, and easy to fall into local minimum values in the image denoising process of traditional BP neural networks, the HS-LMBP hybrid neural network image denoising algorithm is proposed which combines the harmony search algorithm and the LMBP algorithm. The HS-LMBP hybrid neural network algorithm combines the high speed of the LMBP algorithm and the global nature of the HS algorithm, which can be a good improvement to the existing problems of the BP algorithm model. Compared with the Wiener filtering, BP, LMBP and PSO-LMBP model image denoising effects, the denoising model using HS-LMBP neural network algorithm has a better denoising effect.

Rewritable collinear holographic image storage was realized in a genetically mutated bacteriorhodopsin BR-D96N film by using its photochromic property.For a BR-D96N film with 3.0 optical density,under 632.8 nm,700 mW/cm2 recording light(optical reference ratio is about 1∶1.2),the optimum recording time is about 3 s,the optimum reconstruction light intensity is about 50 mW/cm2,and the safetime of the hologram is about 10 min.The experiment shows that,in collinear holographic storage system,simple optical setup,small volume,low environmental effect and the high density storage can be realized;and it is proved that the BR-D96N film has advantages like short storage time,high light sensitivity,high reversibility,long-term stability and easy used,which can be used as a higher sensitive rewritable collinear holographic storage media.

The implementation of image contrast reversal by using a photochromic material of Bacteriorhodopsin (BR) films is demonstrated with two methods based on the optical properties of BR. One is based on the absorption difference between the B and M states. Images recorded by green light can be contrast reversed readout by violet light. The other is based on the photoinduced anisotropy of BR when it is excited by linear polarization light. By placing the BR film between two crossed polarizers (i.e. a polarizer and an analyser), the difference of polarization states of the recorded area and the unrecorded area can be detected, and thus different contrast images can be obtained by rotating the polarization axis of the analyser.

We investigate the photoinduced anisotropy of a photochromic material of pyrrylfulgide/PMMA films. It is proven that when the film is illuminated with a linear polarization light, an optical axis that has the same polarization as the excitation light could be induced in the film. A matrix of light spots with different polarizations is recorded on the pyrrylfulgide/PMMA film. When reading out with non-polarization light, the matrix of light spots shows no information of patterns. However, when reading out with different linear polarization lights, different patterns could be observed. The experiment confirms that the pyrrylfulgide/PMMA film could be used to record two different polarization patterns in a matrix of spots. This property may be applied in camouflage technology.

A biophotochromic material, i.e., genetic mutant bacteriorhodopsin (BR-D96N), was experimentally studied on its holographic recording properties. The saturation absorption curve and the diffraction efficiency curve were measured respectively. As holographic storage application, reflection type polarization holograms were recorded on the BR-D96N film. The 173° configuration between the object and reference beams proves that the spatial resolution of the film is over 6000 lines/mm. By using phase conjugate wave of reference beam as reconstruction beam, the distorted object image introduced by the optical components and the defects in the recording medium can be well corrected.

Holographic Image Storage with a 3-Indoly-Benzylfulgimide/PMMA Film

Based on the equation satisfied by optical pulse that is a slowly varying function, the higher-order nonlinear Schrodinger equation (NLSE) including Raman gain and self-steepening effect is deduced in detail, and a new Raman gain function is defined. By using the split-step Fourier method, the influence of the combined effect between Raman gain and self-steepening on the propagation characteristic of dark solitons is simulated in the isotropic fiber. The results show that gray solitons can be symmetrically formed by high order dark soliton, however self-steepening effect will inhibit the formation mechanism through the phenomenon that gray solitons are produced only in the trailing edge of the central black soliton. Meanwhile, the Raman gain changes the propagation characteristic of optical soliton and inhibits the self-steepening effect, resulting in the broadening of pulse width and the decreasing of pulse offset.

Not only the interaction between optical pulse and orbital electron but also the interaction between optical pulse and optical phonon needs to be considered when input pulse energy is large. The latter induces the simulated Raman scattering, thus generating the Raman gain. We analyze the effect of Raman gain, especially parallel Raman gain, on dark soliton trapping in high birefringence fiber by analytical method and numerical method. In the first part, we introduce some research results of soliton trapping obtained in recent years. In the second part, the coupled nonlinear Schrödinger equation including Raman gain is utilized for high birefringence fiber. The trapping threshold of dark soliton with considering the Raman gain is deduced by the Lagrangian approach when input pulse is the dark soliton pulse that the amplitude of two polarized components of the dark soliton are the same (see formula (26)). Fig. 1. shows the relation between threshold and parallel Raman gain according to formula (26) when group velocity mismatching coefficient values are 0.15, 0.3, and 0.5 (vertical Raman gains are all 0.1). In the third part, the propagation of the two orthogonal polarization components of dark soliton is simulated by the fractional Fourier transform method. Figures 2-4 show respectively dark soliton trapping with group velocity mismatching coefficient values of 0.15, 0.3 and 0.5. We consider three situations in which Raman gain is not included and the parallel Raman gains are 0.4 and 0.6 when vertical Raman gains are both 0.1 in different group velocity mismatching coefficient values. We obtain the threshold of dark soliton by numerical method under different conditions and analyze the figures. At the same time, we compare the analytical solution with the numerical solution and discuss the effect of Raman gain on dark soliton trapping. The last part focuses on our conclusion. It is found that the threshold which is obtained by analytical method is smaller than that from the numerical solution. The difference between the analytical and numerical dependences decreases with group velocity mismatching coefficient decreases. As a result, formula (26) is in good agreement with numerical data for small group velocity mismatching. The larger the group velocity mismatching, the larger the amplitude threshold of dark soliton is. It also shows that the amplitude threshold of dark soliton can be reduced due to Raman gain and the threshold is reduced faster with the increasing of Raman gain.

Using the coupled nonlinear Schrödinger (CNLS) equation containing the Raman gain, the Duffing equation with Raman gain is derived, which is represented by the Stokes parameters, and then the elliptic integrals are used to compute the analytical solutions. This article focuses on the analysis of the Raman gain influence on the evolution of the polarization state when the optical waves are propagating in a low-birefringence fiber. Results show that the transmission cycle of the polarization evolution state can be changed due to Raman gain, if the input power and motion constants have a certain relationship.

The coupled nonlinear Schrödinger (CNLS) equation including Raman gain has been utilized for birefringence fiber. Evolution process of the optical soliton pulse has been simulated by the fractional Fourier method when the optical soliton pulse transmission in a birefringence fiber has a different nature. Results show that the drift of soliton caused by nonlinear coupling effect can be suppressed by Raman gain, at the same time, the soliton pulse peak in the transmission is enhanced. The interaction between optical solitons can be effectively restrained by Raman gain in the birefringence fiber.

Using the nonlinear Schrödinger equation (NLSE) including Raman gain effect but ignoring fiber loss situation, the linear operator and nonlinear operator specific expression are obtained based on MATLAB fractional Fourier numerical algorithm. They are applied to the NLSE including Raman gain, and the evolutions of soliton pulse are simulated in optical fiber through changing parameters. The result shows that soliton propagation stability is destroyed compared with the case considering no Raman gain, leading to the rapid attenuation of optical soliton. The influence degree depends on input soliton pulse peak power. The effects of Raman gain on ground state soliton and high order soliton are not the same.