This PDF file contains the front matter associated with SPIE Proceedings Volume 7009, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

Low transparency current density and improved temperature stability with a large characteristic temperature T₀ > 650 K up to 80 °C are demonstrated for 1.3 μm MBE grown InGaAs quantum dot (QD) edge emitting lasers. Digital modulation with an open eye pattern up to 12 Gb/s at room temperature and bit error rate below 10^-12 for 10 Gb/s modulation was realized for this wavelength. Semiconductor optical amplifiers based on InGaAs QD gain media achieved a chip gain of 26 dB. A conventionally doped semiconductor DBR QD-VCSEL containing 17 p-modulation doped QD layers demonstrated a cw output power of 1.8 mW and a differential efficiency of 20 % at 20 °C. The maximum -3dB modulation bandwidth at 25 °C was 3 GHz. First MOCVD-grown QD-VCSELs with selectively oxidized DBRs and 9 QD-layers were realized, emitting at 1.1 μm. A cw multimode output power of 1.5 mW, 6 mW in pulsed operation, and an cw external efficiency of 45 % were achieved at 20 °C. The minimum threshold current of a device with 2 μm aperture was 85 μA.

VCSELs have several advantages with respect to edge emitting semiconductor lasers; one of their major drawbacks is the lack of polarization control due to the almost absence of any selecting mechanism in the resonator and active medium. In this paper we will review a technique based on the integration of a shallow grating into the VCSEL output facet, which gives very good results, provided that a careful design is performed.

A silicon optical bench for flip chip mounted widely tunable modulated-grating Y-branch lasers is presented. Its impact on the static and dynamic performance of the laser device is evaluated and compared with a conventional aluminium nitride carrier. The carriers exhibited similar thermal and static performance but the dynamic performance was limited by the electrode layout and the higher microwave losses of the silicon optical bench. With improved microwave design of the electrodes, flip-chip mounting on a silicon optical bench is promising for low cost assembly of high-speed multi-electrode devices.

Dynamics of change of the laser heterostructure spectral characteristics under alternating strain caused by surface acoustic wave is investigated. The study of spectral distribution of the laser radiation intensity has been also fulfilled to reveal the interaction mechanisms in the studied structures. The interaction models are offered and the theoretical analysis of the obtained experimental data has been carried out. Is shown, that mainly acousto-electron interaction determines surface acoustic wave effect on spectral parameters of InGaAsP/InP laser radiation.

The basic problems of the receiving p-n junctions in ion implanted InSb Mg⁺/InSb after CO₂-laser irradiation and in p-InSb and p-InAs after Ruby laser irradiation are represented. Proper Volt-Ampere characteristics are analyzed. The basic physical mechanisms of receiving these structures are discussed too. Basic cause of difference these p-n junctions is various mechanisms of irreversible interaction light and semiconductor (self-absorption for Ruby laser irradiation and "damage"-absorption for CO₂-laser irradiation).

Our work deals with a new approach to improve the beam quality of diode lasers, which is still insufficient for many applications. We propose time-multiplexing, where several pulsed laser diode beams are guided onto a common optical path. This allows to superpose the power of the diodes while maintaining the beam parameter product of a single laser diode. Pulsed operation of continuous wave laser diodes was shown to be possible up to pulse enhancement factors of ten provided that pulse duration is <300 ns. We use a fast digital optical multiplexer built up by a cascade of binary optical switches. For the latter we use a polarisation switch (voltage-driven LiNbO₃-crystal) followed by a polarisation filter, which allows addressing of two optical paths. Instead of direct on/off-switching we drive the crystals with a harmonic voltage course to avoid ringing caused by piezo-electricity. Up to now an optical power of 10.5 W was generated, 13 W are expected with some improvements. With the use of new 8W laser diodes even the generation of 25 W will be possible.

This paper represents the ability of Multiple Quantum Well (MQW) Laser for remote sensing by image processing of the laser beam cross sectional using the digital camera and personal computer. The magnetic field was applied on the MQW Laser in order to investigate the intensity of laser beam and the beam cross sectional. Analyses were pursued using Matlab package on the recorded images of the laser spot carried out using the digital camera. The results indicated that 20% increment in the intensity and 30% decrement in the cross sectional of the laser beam due to applied magnetic field of intensity 2.4 Tesla, in accordance with the original properties of the laser without magnetic field. These results could be properly used for remote sensing of the any sudden change in the environmental conditions of electrical high power stations and nuclear reactors.

The thermal dependence of mirror reflective properties in oxide-confined VCSEL is investigated. The temperature distribution over the cavity versus applied current is calculated. The refractive indexes of the mirror layers are redefined by using the temperature coefficients, and changes in radial reflectance spectra of the mirror are analyzed. Results show a shift of stopband and Bragg wavelength DBR as well as shift of laser operation wavelength at different injection currents and the formation of the temperature lens in the mirror due to decreasing the temperature close to edge of oxide windows.

In this paper we calculate the spatial dependency of the spontaneous emission in semiconductor laser cavity using a model based on transmission line laser method (TLLM). Results show that in the simple ridge laser structure, the major part of the spontaneous emission occurs at the middle of the cavity and so uniform spontaneous emission can't be assumed.

An optical communication network using multimode fiber was implemented. Characteristics of direct modulation of the laser diode at different bias currents and many bit rates at a stabilized temperature will be presented. Many modulation schemes have been involved in the investigation. Mach-Zehnder modulator, based on LiNbO₃ substrate, had been used for the modulation of the laser diode light output as analog-amplitude modulated signals. Fourier-transform of the power output will be presented at different bias currents. Results will be compared to the direct modulation of the laser diode for the pulse dispersion.

High brightness, high power, semiconductor lasers have many potential applications such as: free space communications, printing, material processing, pumping etc [1]. Such applications require lasers, which are characterized by reliability and long lifetime. Catastrophic optical mirror damage (COMD) process is one of the major mechanisms, which drastically limits laser lifetime and emitted optical power [2]. Mirror degradation and eventually destruction of lasers is caused by facet heating due to nonradiative surface recombination of carriers. Facet heating reduces the band gap energy, consequently increasing the absorption coefficient at the facet. The absorbed light and photo-induced electron-hole pair are increased by the increase in the absorption coefficient. Both effects lead to further nonradiative recombination of carriers which induces heating and so on, up to degradation of mirror or even destruction of laser. We see that this effect is very undesirable and knowledge of the temperature dissipation on the surface is very important for improving semiconductor lasers design. In this work we present the analysis of temperature distribution at the front facet of the broad area GaAsP/AlGaAs lasers by means of micro-Thermoreflectance (μTR) Spectroscopy. Several methods proved to be useful in determining the temperature of the laser surface. These are micro-probe band-to-band photoluminescence, thermoreflectance spectroscopy and Raman spectroscopy [2, 3, 4, 5]. We have used μTR because it is contactless, non-destructive technique which enables us to obtain temperature distribution in real time.

The influence of the geometrical and physical parameters on the photonic band-gap of GaAs and AlGaAs 2D photonic crystals has been investigated. As a result the gap-maps for geometrical parameters appropriate for operation at around the λ = 1.5μm wavelength have been obtained, i.e. the wavelength region most widely used in current fibre-optic telecommunications. Using these gap-maps, it is possible to find the PhC parameters for which the PhC exhibits a PBG within the telecommunication range.

New phenomenon predicted earlier - failure of phase conjugation at the stimulated Brillouin scattering (SBS) of focused laser beams with screw dislocation of phase front (Laguerre-Gaussian vortex modes) - has been experimentally confirmed Phase conjugation of vortex beams does not take place as a phenomenon because of failure of selection of Stokes mode conjugated to laser one. It occurs since the SBS amplification coefficient does not depend on the laser field phase, and the Stokes field does not "feel" how the laser phase helix is twisted. Therefore the amplification coefficients of a Stokes conjugated mode and an analogous mode of opposite helicity are equal to each other. For example, in the case of a doughnut laser LG₀¹ mode the Stokes beam consists of a random superposition of a few modes including conjugated one. For rather wide class of vortex beams (for example, in the case of a laser LG₁¹ mode with two rings), a novel phenomenon takes place that can be called as phase transformation at SBS. Its essence is in the fact that in Stokes beam a mode with regular phase front is selected, which is orthogonal to laser mode at all. In the near-threshold SBS regime, this selected mode is close to a principal Gaussian mode. At SBS of the vortex laser beam the generation of the vortex hypersonic wave takes place in the SBS-medium so that the topologic charge in the system "Stokes wave+hypersonic wave" is equal to the charge of incident laser wave.

We present the theoretical model of coherent interactions of the light beams in a two-level resonant medium, taking into account a spatial-periodic modulation of the parameters of nonlinear medium in an interference field as well as nonlinear behavior of refractive index and absorption coefficient due to optical bleaching. As evidenced by the results of investigations described in this work, the process of the light beams interaction via scattering from dynamically induced optical gratings in two-level resonant medium is characterized by a number of interesting features like mutual attraction and repulsion, irradiation of additional beams probably due to soliton-soliton diffraction mode, formation of dark spatial solitons in the mode of defocusing interaction that can be used for all-optical control over the spatial structure of laser beams. Formation of bound states of spatial cavity solitons upon intracavity four-wave mixing and possibilities for control over all-optical soliton-based operations are also discussed.

In this paper, we discussed the behavior of bright soliton solutions to the NLS equation and their interactions then investigated dark solitons and their formation within an attractive potential and applied them to Bose-Einstein Condensation using fast and efficient finite difference scheme. We report numerical results for intersite collisions between solitons in the discrete nonlinear Schrodinger model. We systematically examine the dependence of the collision outcome on initial velocity and amplitude of the solitons, as well as on the phase shift between them, and location of the collision point relative to the lattice.

We present a detailed study of the localized coupled-cavity modes in a photonic molecule formed from two dielectric spherical microcavities with CdTe nanocrystals. A layer-by-layer deposition technique provides controllable coating of the microspheres with a shell of close-packed nanocrystals of approximately 4 nm in diameter. The observed spectral structures originate from the coupling of the electronic transitions in nanocrystals and the photon states of interacting microspheres and, in analogy to the formation of molecular electronic orbits, can be assigned to bonding and antibonding photon localized states.

Using quasiclassical approach rather precise analytical approximations for the eigenfrequencies of whispering gallery modes in convex axisymmetric bodies may be found. We use the eikonal method to analyze the limits of precision of this approach using as a practical example spheroidal dielectric cavity. The series obtained for the calculation of eigenfrequency is compared with the known series for dielectric sphere and numerical calculations.

Nonlinear processes of branched waveguiding structures optical synthesis at light-beams interaction in transparent photopolymerizable compositions are investigated numerically and experimentally as well.

A contradiction between high efficiency of an amplifier operating in a saturated mode, and nonlinear distortions in image reproduction characteristic for this regime is solved. A lasing medium is located in a Fourier-plane of the image, its gain profile being specially shaped, while the amplified image is illuminated by a laser beam which angular divergence is appropriately formed. Criteria for the gain shape and beam divergence are formulated. A possibility for correct amplification of binary and/or half-tone images with high efficiency of energy stored in the laser medium (up to 70%) is shown. The results are applicable for laser image projectors of systems of virtual reality, simulators, etc., providing images with high dynamic range (e.g., pictures of illuminated landing stripes, approaching car lights, etc.).

Coherent light self-modulation process was studied by modeling the running wave interferometers scheme containing beam splitting, delaying and amplifying. Principal possibilities of cw laser light modulation with GHz - THz frequencies and amplified pulses formation by cw pumping are shown. Some scheme parameters and input light features influences on said processes are illustrated and discussed. Pulse transformation in running wave interferometers (with and without amplification) was also studied by computer modeling. Pulse compression along with pulse form changes and specific pulsing generation with cw pump were found.

A transformation of a higher Gaussian beam in general astigmatic optical systems is described in terms of rotations in 3D space. This way is simpler than direct Fourier integral calculation and preferable for numerical simulations. Two examples of optical systems and corresponding transformations, connecting with mode converter and fractional Fourier transform, are discussed.

The transmission characteristics of the dielectric grating - thin metal film - dielectric grating structure have been analyzed by the coupled wave method (CWM). The analysis is conducted for waves of TE and TM polarizations. The qualitative transmission characters are similar for two polarizations, but are different quantitatively. The reflectance of such structure can be higher than 0.85 on wavelength of 1.5μm at certain parameters for a silver film with thickness of 0.0385μm. The reflectance on the wavelength of the maximum transmission is actually equal to zero. The only thin film without gratings on the same wavelength has the transmittance of 0.004 and reflectance of 0.984. The system, which consists of grating from metal included between homogeneous dielectrics, also possesses by anomalous high transmission. At that the transmission is substantially higher than a ratio of a metal-free space to the grating period. Similar dependences can be obtained for a structure, in which the thin film of metal is located between two layers of dielectric with high refraction index. At certain conditions the reflection is less than 0.0002 and transmission is more than 0.87 for the metal thickness of 0.0385 μm. The rule is found, which is enable to find approximately the parameters for these high transmission structures. This effect is explained by the coupled wave resonance with forming of a wave node within the thin metal film that minimizes absorption.

The influence of gas mixing ratio on stability of quasi-steady mode of electro-discharge XeCl-lasers operation is discussed. The simplified model for electric-discharge XeCl-laser is presented. Although there are many reports on the models of XeCl-laser, for an analysis having clear physical sense it is useful to have a simplified kinetic model. The model enables to calculate an electrons concentration, density of excimer XeCl* molecules and specific energy deposition in active medium. The quasi-steady mode of discharge in XeCl-lasers is analyzed.

The not weakening interest to excilamps is bound to a possibility of reception of power impulses in the UV-field of a spectrum with significant average power. These experimental compact models of excilamps are designed for different applications in the field of medicine, biology, spectroscopy and so on. The lamps are executed on the basis of serial domestic elements and blocks of own production. The lamps differ by compactness and simplicity of construction.

With the purpose of reception of energy of generation 0,2-1 J, two types of electrodischarge XeCl-laser excitation system with was created. The modeling procedure of XeCl-laser excitation systems is developed, allowing calculate the form of a voltage pulse on laser electrodes and energy input in the active medium. The dependence of discharge gap resistance on time is usually simulated by exponential empirical dependence. In this case the breakdown voltage of inter-electrode gap must be taken from experimental data also. For each gas mixture, parameters of time dependence of discharge gap resistance and value of inter-electrode breakdown voltage have different values. Consequently, the results, which are obtained in this manner, have practical significance for definite gas ratio of mixture. We have developed the simple model, which takes into account the dependence of discharge gap parameters from gas pressure and composition. The solution of Boltzmann equation for electrons in electrical field (E/N) and calculation of kinetic processes may be carried out. In this case the effective rate of electrons formation may be approximated as function of gas composition and (E/N). Results of one model are compared to results of other model and experimental data.

Numerical solution of gas-dynamic laser equations in a gas mixture CO₂:N₂:H₂O was carried out, using five-temperature-model (one translational and four vibrational temperatures) by a computational program written in FORTRAN. The spatial distributions of population inversion, gain and temperatures of the gas flow, in addition to the laser intensity and power extraction were studied inside the cavity, for certain initial conditions like pressure (p₀=20 atm), temperature (T₀= 1500 K), ratio of gases in the laser mixture (CO₂:N₂:H₂O ≡ 10:85:5).

The model of calculation of a cavity configuration of the axially diode pumped solid-state laser which considers nonlinear dependence thermo-optics distortions (a thermal lens) in the active element on the pumping power has been presented. Quantity (focal distance) of a thermal lens in the crystal has been determined by means of Hartmann method. Within the bounds of model the main spatial characteristics of the output laser radiation - the energy divergence angle and output beam diameter for two cases of cooling of the active element were determined. It is shown that experimental investigation of beam quality of the laser radiation is in correlation conformity with theoretical calculations.

Mode-locking characteristic of hybrid soliton pulse source (HSPS) utilizing linearly chirped raised-cosine flat top apodized fiber Bragg grating (FBG) is investigated by using coupled-mode equations. It is shown that proper mode-locking range where transform-limited pulses are generated is increased to 1.3 GHz by using linearly chirped raised-cosine flat top apodized FBG.

The method of a focusing objective, spatial spectrum, based on the analysis, of images is circumscribed. The theoretical substantiation is shown it. Is shown, that for a surface of any object exists of one or several resonant spatial frequencies, which in a focal point have maximum intensity. It is connected to a method of formation of a roughness. Because of theories of stochastic and random oscillations, is asserted, that all actual rough surfaces are not absolute random in a sense of a theory of probabilities. Therefore, optical fields generated by these objects, too not random. The image in this case grows out interactions of a field with a screen. Such submission has allowed to use as the characteristic of an optical field correlation dimensionality of its spatial chaos. The conducted researches have allowed to combine process of precision guidance on a focal point of the technological laser with obtaining of a sharp image of a treated surface.

Single-photon detectors (SPDs) are the foundation of all quantum communications (QC) protocols. Among different classes of SPDs currently studied, NbN superconducting SPDs (SSPDs) are established as the best devices for ultrafast counting of single photons in the infrared (IR) wavelength range. The SSPDs are nanostructured, 100 μm² in total area, superconducting meanders, patterned by electron lithography in ultra-thin NbN films. Their operation has been explained within a phenomenological hot-electron photoresponse model. We present the design and performance of a novel, two-channel SPD receiver, based on two fiber-coupled NbN SSPDs. The receivers have been developed for fiber-based QC systems, operational at 1.3 μm and 1.55 μm telecommunication wavelengths. They operate in the temperature range from 4.2 K to 2 K, in which the NbN SSPDs exhibit their best performance. The receiver unit has been designed as a cryostat insert, placed inside a standard liquid-heliumstorage dewar. The input of the receiver consists of a pair of single-mode optical fibers, equipped with the standard FC connectors and kept at room temperature. Coupling between the SSPD and the fiber is achieved using a specially designed, precise micromechanical holder that places the fiber directly on top of the SSPD nanostructure. Our receivers achieve the quantum efficiency of up to 7% for near-IR photons, with the coupling efficiency of about 30%. The response time was measured to be < 1.5 ns and it was limited by our read-out electronics. The jitter of fiber-coupled SSPDs is < 35 ps and their dark-count rate is below 1s^-1. The presented performance parameters show that our single-photon receivers are fully applicable for quantum correlation-type QC systems, including practical quantum cryptography.

In this article we propose and analyze in detail the new scheme of laser interferometric gravitational-wave detector. This scheme is based on so called "intracavity" topology of gravitational-wave detectors that allows, in principle, to achieve sensitivities significantly better than the Standard Quantum Limit (SQL) using relatively small amounts of optical pumping power. The key element of any intracavity scheme is the local meter that allows to measure in a quantum non-demolition (QND) way the redistribution of optical energy inside the scheme caused by gravitational wave. Here we analyze practical design of such a meter and calculate the sensitivity limitations it imposes on the considered detector. We show that using the proposed design one is able to increase gravitational-wave detector sensitivity several times compared to the SQL. We also compare the proposed intracavity scheme with other candidates for implementation as advanced laser interferometric gravitational-wave detector and analyze advantages and disadvantages of different schemes.

In this paper, a circuit model of a segmented traveling-wave Electroabsorption modulators is presented for the circuit level simulation of single device or Optoelectronic Integrated Circuits (OEIC) including modulators. Using this model, the frequency response of segmented TEAM are analyzed using HSPICE. The analysis indicates that STEAM can achieve much wider bandwidth than the LEAM and TWEAM counterparts, with a small penalty in E/O conversion gain if low loss passive optical waveguide is available.

We present the analysis of a nonlinear effect of parametric oscillatory instability in power recycled LIGO interferometer with Fabry-Perot cavities in the arms. The basis for this effect is the excitation of the additional Stokes optical mode and the mirror elastic mode when the optical energy stored in the main Fabry-Perot cavity mode exceeds the certain threshold. We demonstrate that in the resonance case the parametric oscillatory instability will take place at the energy stored in the cavity of about five orders smaller than one planned for LIGO-II interferometer. The presence of anti-Stokes modes can depress parametric oscillatory instability. However, it is very likely that the anti-Stokes modes will not compensate the parametric oscillatory instability completely because of the existence of the mode combinations which interact with each other quite strongly.

Simple and small laser interferometers for the Space optical systems testing are discussed. Interferometer consists of a lens in front of the gas laser, flat pellicle beamsplitter, a tiny flat reference mirror, and optics under test. The interferometer is not affected by displacements and the tilts of the lens, the beamsplitter, and the the reference flat mirror, that it is especially recommended for the Space optics testing on the orbit.

In this paper, various noninterferometric measurement schemes for determination of single-mode optical fiber nonlinear coefficient are reviewed, studied and discussed. All of proposed measurement techniques use one of the Kerr-related phenomena, which are self-phase modulation, modulation instability, cross-phase modulation or four-wave mixing. Some of the methods applied to determine the nonlinear coefficient are based on pulsed lasers instead of continuous wave sources. The brief description of each measurement scheme and method is given. This paper focuses on the comparison of different noninterferometric measurement schemes in terms of their construction set-up simplicity, equipment cost, measurement time and field usage. In many of the measurement techniques, presented in this paper, the accurate determination of the input power becomes a critical factor to reduce the measurement uncertainty. Versatility of testing the various types and lengths of fibers is also an important issue in the design of optical devices and systems.

A physical model for the analysis of dynamic response of a voltage- tunable optoelectronic integrated device is outlined. The device is composed of an integrated quantum well Heterojunction Phototransistor (HPT) over a strained quantum well Laser Diode. The quantum well structure Hamiltonian is numerically solved by transfer matrix method to obtain the electron and hole subband energy levels taking in to account the valence band mixing effect and strain. In order to calculate the electroabsorption coefficient, the exciton equation is solved numerically in momentum space using the Gaussian quadrature method assuming parabolic band structure. Based on the model the device has two operation modes: amplification for small optical feedback coefficient and switching for higher values.

The propagation of acoustic waves through interface of two crystals is studied on microscopic level using the discrete lattice model. It is considered phonon transmission through intercalated layer between two semi-infinite lattices. The general expressions for energy fluxes and impedances are proposed. Resonance transmission of phonons through the interface of the 3D pressure made KBr-Cu and Si-Cu point contact was studied using the discrete model of crystal lattice. We show that anomalous behavior of the reduced heat flux in the temperature range 1K