We describe how the data carrying capacity of a multimode fiber can be increased by spectrally modulated space-time encoding of its spatial mode structure. The operation of such an optical communication system is demonstrated by experiments and simulations.

The principle of optical information collection from the fiber-optical measuring network (FOMN) is submitted. The principle of functioning 1-Wire network standard lays in the basis of the implemented method. The represented device is a function block, intended for collecting optical information from 4 fiber-optical measuring line (FOML), converting optical information into digital signals and delivery of digital information about intensity of laser radiation into FOML. The device has a very small amount of elements, that considerably makes more cheap practical realization of such blocks, has small overall dimensions and good operating performances.

We propose a method to obtain intensity chaos of high dimensionality from a laser diode with a nonlinear delayed feedback. The core of the chaotic transmitter and receiver is formed by an electro-topic LiNbO3 modulator that is used to generate strong nonlinearities and chaotic waveforms. The method can be used for encrypting and decrypting a signal in a chaos-based communication system.

Algorithms of designing planar shift optical arrays of hexagonal topology on the basis of a 4-pixel switching Y-nodes are considered. Y-node of micrometer size is realized experimentally with the use of optically bistable vacuum deposited ZnS interferometer.

All-optical data shift operation in a planar array based on transverse effects in optical bistability in an all-epitaxial GaAs/GaAlAs Fabry-Perot interferometer is reported. Transfer of information bit along a shift register takes about 6 ns.

The possibility of use of nonlinear ring interferometer (NRI) for protect of information was shown by the authors earlier. How does the mismatch of the principal physical factors influence the error of deciphering in the model of cryptosystem based on NRI? It appears that this error can be submitted as a wave process. The analytical experessions for amplitude and phase of this process are obtained. These expressions do not contradict results of author's computing experiments. Obtained results allow to estimate power of keys set as quality criterion of antiwiretap enciphering.

Application of wavelets is investigated with ultimate time-frequency resolution for laser communications. The optimum encoding method for reaching the maximum rate of information transmission is shown to be based on WAVE-wavelets.

Information-rate densities in optical communication systems are investigated on the base of the number-state model. Results of numerical simulation show that the considered characteristics increase monotonically with increasing signal power, reducing passband width and environment temperature. For quasi-monochromatic optical communication channels quantum-statistical peculiarities of information carriers can not be taken into account at large enough singal powers when fluctuation noise can be neglected.

Technical parameters and main experimental features of laser complex for investigation of bistable phenomena in GaAs/GaAlAs interferometers and for modeling basic digital devices for optical signal processing (logical elements, switching devices, etc.) are reported.

In development of various devices on the basis of IR fibers is very important to know such their optical characteristics as spectral transmission, numerical aperture, far-field divergency with various conditions of fiber launching and, in particular, stability of these characteristics with fiber length. In the present work the results of research of changing the specified above characteristics with length in polycrystalline AgHal-fibers are presented. It is shown, that the total optical losses in these fibers change along the fiber and follow the variations of losses in original crystal. The practical recommendattions of fiber choice for various applications are given.

The method of data analysis in intracavity laser spectroscopy is considered. The artificial neural network was used as an analyzing tool for the determination of elements concentration in trace amounts samples using absorption spectra. The special neural network training algorithm based on simulation of experimental spectra was developed to solve the problem of non-sufficient experimental data set. The application of this method allows achieve the better sensitivity than conventional analytical methods and proved itself more robust. The proposed method was tested on spectra of Cs water solution.

A new type of flexible THz-wave hollow waveguide was developed using ferroelectric polymer PVDF as the cladding material of the waveguide. The transmission efficiency of the PVDF waveguide was better than a metal coated hollow waveguide with the same size and structure as the PVDF waveguide. We also report the tilt-angle dependencies of the transmission efficiency of the hollow PVDF and metal waveguides. The polarization dependency of the PVDF waveguide was better than that of a metal waveguide.

Reflectivity modulating spatial optical communication has been researched using liquid crystal light modulator and corner-reflecting device for an adequate human-supporting information service environment. Conventional polymer dispersed liquid crystal light modulator had a subject of its response speed. In this paper, characteristics of a ferroelectric liquid crystal light modulator device are reported to improve its communicating data rate. A technique for higher data rate using a high-speed vision chip is also mentioned.

We report the theoretical and experimental results of dynamic holograms recording in nano-size porous glasses containing fullerine C₆₀ and its use for optical limiting. To record a grating with spatial frequency 20 mm^-1 we used laser pulses with 18 ns duration and 532 nm wavelength. Initial transmittance of the samples varied from 30% to 70%. We found that high diffraction orders appeared out of the medium during the experiment and investigated dependence self-diffraction on initial transmittance of the samples and in case when the samples were filled by toluene. It was found that the most effective self-diffraction is in situation when we use toluene and initial transmittance of the sample is nearly 70%. For explanation of our experimental results we made a numerical model of dynamic hologram in fullerene-containing media taking into consideration amplitude and phase grating forming during the pulse length. Our model showed good agreement with experimental results.

Fiber quality estimation by holographic interferometry correlator is presented. The method gives the possibility to test fiber seams and quality homogeneity of the fiber in the laboratory condition. The method is very simple and gives one possibility to provide automatic control of the fiber fabrication.

Some new results of experimental study of multifrequency χ⁽²⁾-dynamic hologram image formation are presented. The main distinguishing feature of our experiments was the use not only of a multifrequency object wave but a multifrequency reference one, too. As a result, we have simultaneously observed at the same wavelength (λ=564 nm) two frequency summing holographic images formed by nonlinear crystal KTP and arranged nearly symmetrically around SHG image (λ=432 nm) both in transverse and longitudinal directions according to the theoretical treatment. These images can be used for noninertial optical channels switching and addressing with change of wavelength and spatial localization of images including the information.

We study the two-dimensional interleaving for volume holographic data storage systems suffering from both random and systematic errors and propose cyclic shifting as a general interleaving technique for volume holographic memory that can accommodate some range of systematic errors. This technique is simple, and can reduce the complexity of error-correcting code with minimal cost.

The surface relieves shaped in processes of thermoannealing of exposed polymer layers containing photosensitive admixtures are investigated. Several ways of resolving ability improvement of the relief recording are proposed and implemented experimentally. They are based on: (1) retardation of deformation reate, (2) depression of glass transition temperature of a polymeric matrix, (3) considerable increase of annealing temperature of the samples and (4) overlapping of the recording and thermal developing processes under photorelief shaping by one laser pulse. The last method has made it possible to record surface gratings with spatial frequencies in the limits of 50-1500 mm^-1.

iSCSI builds on SCSI command for storage and TCP/IP protocols for networking. As a new storage technology, VHS has advantage of huge capability and fast data transfer rate. This paper presents a detailed design, based on Intel's network processor and embedded Linux OS, to implement embedded VHS system in which unites iSCSI and VHS technologies.

Three types of tunable and reconfigurable holographic filters based on photorefractive crystals were experimentally demonstrated. The filters exhibit an extremely narrow bandwidth (better than 0.1 nm) and allow reconfiguration or switching in a broad range of wavelengths and precise frequency trimming.

It is theoretically shown on the example of a lensless Fourier hologram, that additional channels of associative data reconstruction are possible in the system, composed of a thin linear superimposed off-axis hologram and a phase-conjugating mirror. Due to the "phase-retaining" nature of a phase-conjugating mirror, partial transformation of noise field components (which are nonlinear on amplitudes of fields and can't be interpreted as an image or a correlation peak) into information field components takes place in such a system. Taking it into account and assuming certain opportunities of phase-conjugating reflection control make it possible to consider the system as a quadratic hologram with modifiable response. Possibilities of data processing by all the channels are considered.

The peculiarities of optical recording in the films of azo dye containing amorphous and liquid-crystalline polymers have been studied experimentally and theoretically. A simplified theoretical model of light induced processes in the azocontaining media has been elaborated. The model considers interaction of linearly-polarized light with a thin polymer layer. We derived analytical expressions for the light-induced refractive index and the absorption coefficient. Theoretical results are in good agreement with the experimental data. We have investigated features of holographic recording in amorphous and liquid-crystalline polymer samples. Recording of multiple holograms in polymer films with different structure was also demonstrated.

The propagation and the stability of sequences of dissipative solitons in fibers with gain, saturable absorption, and spectral band limitation of radiation has been analysed. The spectrum dependence for a gain is approximated by a squared frequency dispersion. The spectrum-dependent loss related with the additional spectral limitatiaon is modeled by a fourth order frequency one. It is found that the combined action of the nonlinear refractive index inducing a frequency soliton chirp and of the indicated spectral limitation causes the negative feedback. By the action of this negative feedback and the positive feedback due to saturable absorption on propagating pulses, the dissipative soliton sequences is stabilized: the weak noise pulses are suppressed, the powerful signal solitons with different amplitudes are equalized. The found stabilization can present interest for a management of sequences of dissipative solitons in fiber lines.

The spectral compressor completed by a spatial phase and amplitude mask placed in the dispersive delay line of spectral compressor modified it to the effective generator of dark solitons. Spectral evolution of generated dark soliton contains enough information about soliton character of the radiation.

New linear effects for the coherent ultrashort laser pulse trains are considered. The processes of envelope compression for two pulses and regular and irregular multiplying a number of pulses due to temporal interference are predicted.