Based on the theory of semiconductor laser pattern and the non-paraxial vectorial moment theory of light beam propagation, the beam quality factor M^(2) of TE_(0) propagating mode is analyzed and calculated. The result shows that when both core layer and cladding layer are considered, M^(2) &gt 1 is always obtained. Moreover, by analyzing the characteristic of real beams, this result is generalized to the multilayer isotropic linear slab waveguides.

A simple method to mechanically induce a long-period fiber grating (LPFG) by a grooved plate is improved. The transmission spectra of a grating under different pressures and other types of gratings are experimentally investigated. This method is simple and reconfigurable and offers large spectra tunability. This type of LPFG has potential applications in gain flattening in erbium-doped fiber amplifiers (EDFA) and will be of particular use in filter design.

We report an experiment of adaptive compensation for first-order polarization mode dispersion (PMD) in 10-Gb/s return zero (RZ) optical communication system. The compensated differential group delay (DGD) is up to 30 ps. The quasi-real-time, less than one second, PMD compensation is realized. In the experiment, for the first time, the algorithm so-called particle swarm optimization (PSO) is used to control feedback compensation system.

A novel compensation method for temperature-dependent gain tilt of L-band erbium-doped fiber amplifier (L-EDFA) is proposed, in which the attenuation between stages is the only parameter to be adjusted. A simple linear relationship between the attenuation and the erbium fiber coil temperature was derived theoretically. When the erbium fiber coil temperature cycles from 26 to 70 ℃, the gain tilt variation less than 0.3 dB is achieved experimentally by adjusting only the pre-inserted variable optical attenuator (VOA).

The concept of mobile atmospheric laser communication (MALC) is introduced in this paper. Atmospheric attenuation, turbulence-induced scintillation and beam wander cause deep fades in the beam power and degrade the optical channel. The optical transceiver presented in this paper is designed for a MALC test system. Currently achievable hardware performance capabilities for the MALC terminals are used as input parameters to the analysis. A novel optical transceiver structure is designed. Link margin is analyzed using the MALC analysis software, our optical link analysis program. Data rate, bit-error rate, prime transmit power requirements, optical link margin, pulse width, background signal, aperture quality and atmospheric effects drive the optical transmitter requirements. Results are displayed as required aperture size, aperturenumber and the spacing between apertures for a given range and terminal moving speed. The aperture size is parameterized by data rate, transmitting optical power and wavelength. Si-APD and CCD are selected as the main receive detectors. The receiver aperture, detector size (diameter), receiver speed and sensitivity are the main factors to consider in the design of the receiver.

The formation of the spatial solitons in the quadratic nonlinearity χ^((2)) media by cascading second harmonic generation (SHG) in quasi-phase-matched (QPM) sample is studied on the basis of nonlinear Schrodinger equation (NLSE). When the solitary wave propagates in the QPM media, it formed optical wave-guides through cascading χ^((2)) effect called self-induced soliton wave-guide. Transverse refractive index distribution of the self-induced soliton wave-guide of fundamental and SHG wave is obtained by cascading process. Analysis of guided-mode of such self-induced soliton wave-guide is first proposed to our knowledge. Because the power needed for forming the spatial solitons in cascading process is much lower than that inKerr media, this kind of self-induced soliton wave-guide shows potential applications in all-optical signal process.

A 1 × 25 star coupler is designed through calculation and beam propagation method (BPM) simulation. Improvement methods are focused on the design of the tapered waveguides in the device, improving the uniformity of the output light power of the star coupler. Utilizing the conventional Si process technology, the device is fabricated based on silicon-on-insulator (SOI) material. The test result shows that the star coupler has a perfect function of power splitting.

In this paper, a new photodetector, bipolar junction photogate transistor (BJPG), is proposed for CMOS imagers. Due to an injection p^(+)n junction introduced, the photo-charges drift through the p^(+)n junction by the applied electronic field, and on the other hand, the p^(+)n junction injects the carriers into the channel to carry the photo-charges. Therefore this device can increase the readout rate of the pixel signal charges and the photoelectron transferring efficiency. Using this new device, a new type of logarithmic pixel circuit is obtained with a wide dynamic range which makes photo-detector more suitable for imaging the naturally illuminated scenes. The simulations show that the photo current density of BJPG increases logarithmically with the incident light power due to the introduced injection p+n junction. The noise characteristics ofBJPG are analyzed in detail and a new gate-induced noise is proposed. Based on the established numerical analytical model of noise, the power spectrum density curves are simulated.

Equilateral triangle semiconductor microcavities with tensile-strained InGaAsP multi-quantum-well as the active region are fabricated by the inductively coupled plasma (ICP) etching technique. The mode characteristics of the fabricated microcavities are investigated by photoluminescence, and enhanced peaks of the photoluminescence spectra corresponding to the fundamental transverse modes are observed for microcavities with side lengths of 5 and 10 μm. The mode wavelength spacings measured experimentally coincide very well with those obtained by the theoretical formulae.

Based on the Collins form, the intensity distribution of the resulting beam is derived when Gaussian beams of a high-power laser diode bar pass through a paraxial optical system. Then flattop beam profiles are obtained by a concave cylindrical lens, and the propagation properties are discussed in detail, such as the peak-intensity axis inclined at an angle γ_(i). In addition, an expression to calculate beam angular width is presented.

Stable continuous-wave passive mode-locking of diode-end-pumped Nd:GdVO_(4) and Nd:YAG lasers with semiconductor saturable absorber mirrors (SESAMs) are reported. The comparative study shows that the Nd:GdVO_(4) crystal is efficient to decrease the Q-switched mode-locking tendency, and easier to continuouswave (CW) mode lock than Nd:YAG.

In a diode-pumped, KTP intracavity frequency-doubled green laser, multi-Brewster plates are used to achieve high power single-frequency operation. With a simple experimental setup, single-frequency operation of the diode-pumped green laser with output of 46 and 218 mW is obtained by one and three Brewster plate, respectively.

Cat mutually pumped phase conjugation configuration is discovered and investigated by using two-wave mixing in (K_(y)Na_(1-y))_(2z)(Sr_(x)Ba_(1-x))_(1-z)Nb_(2)O_(6) (KNSBN) crystal. When only one signal or pumped beam does not give birth to phase conjugation, the maximum reflectivity of signal and pumped beam attain 140% and 30% due to two-wave mixing, respectively. The experimental results show that the two-wave mixing can reduce the threshold of incident beams power, extend the incident angle range, and shorten response rate in the process of self-pumped phase conjugator (SPPC) in KNSBN crystal.

The Kerr spectra as function of wavelength, incident angle and layer number are calculated with 4 × 4 matrix method. It is found that the calculated results are in good agreement with experimental ones for [Co (0.3 nm)/Pt (0.4 nm)]×43/glass (1.21 mm) and [Co (0.4 nm)/Pt (1.1 nm)]×53/glass (1 mm). In addition, for [Co (0.3 nm)/Pt (0.4 nm)]×43/glass (1.21 mm), it shows a maximum Kerr rotation at N = 10. For [Co (0.4 nm)/Pt (1.1 nm)]×53/glass (1 mm), the calculated Kerr rotation as a function of incident angle reveals maximum when the incident angle is 89°.

The interaction between an atomic beam of two-level atoms and a standing wave light field has been studied by the exact solution of a time-dependent quantum system developed recently. When the initial atomic state is choosen to be ground, we find that with the limit of zero detuning the atoms will oscillate between the upper and the lower levels with a decaying amplitude. The most interesting result obtained in this paper is when the initial atomic state is a particular superposition of the two levels, now the system does not oscillate at any time.

Proposal for the teleportation of two-atom state is presented. It is based on the simultaneous interaction of two two-level atoms with a single-mode cavity with a filed of n photons. In the proposed scheme, two pairs of EPR state are used as quantum channel to teleport an unknown two-atom state. It is shown that the distinct features of the presented scheme are that the completed time is greatly reduced and cavity field is not required to be detected.

Two-photon laser-induced fluorescence spectrum (TP-LIF) of NO is obtained with a Nd:YAG pumped optical parametric generator and amplifier as radiation source. Spectral intensity distribution shows that the electronic transition moment for NO (A^(2)∑ → X^(2)∏) transition varies significantly with inter-nuclear distance. The variation relationship of the electronic transition moment versus inter-nuclear distance is deduced with polyminal fit procedure. The spontaneous radiative coefficients for NO (A^(2)∑ → X^(2)∏) transition from ν' = 0, 1 are obtained by combing this transition moment variation with the measurements of spontaneous radiative lifetime.

We describe a new method for angular displacement measurements that is based on a Fabry-Perot interferometer. A measurement accuracy of 10^(-8) rad is obtained by use of the sinusoidal phase modulating interferometry. Another Fabry-Perot interferometer is used to obtain the key initial angle of incidence.

Based on Raman-shifted wavelengths of D2 and CH4 pumped by third harmonic of Nd:YAG laser, a differential absorption lidar was presented in this paper and had been constructed for probing environmental NO2 concentration. NO2 experimental measurements were carried out at Anhui Institute of Optics and Fine Mechanics in Hefei. Some NO2 measurement results were given and discussed.

In this letter, it is shown that there exists relationship between phase-based and area-based stereo in spite of their different motivations. A new cost function is defined based on this clue and an improved cost-minimization framework is presented. It is suitable for disparity estimation and occlusion detection in aerial scenes.