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We report the fabrication of a saturable absorber made of a novel polymer SU8 doped with Single Wall Carbon Nanotubes (SWCNTs). A passive mode-locked ring cavity fiber laser was built with a 100 μm thick SU8/SWCNT film inserted between two FC/APC connectors. Self-starting passively mode-locked lasing operation was observed at 1572.04 nm, with a FWHM of 3.26 nm. The autocorrelation trace was 1.536 ps corresponding to a pulse-width of 871 fs. The time-bandwidth product was 0.344, which is close enough to transform-limited sech squared pulses. The repetition rate was 21.27 MHz, and a maximum average output power of 1 mW was also measured.

Annular Photonic structures, which occur on bulk and fibers, are Bragg structures that share both Bragg resonances and waveguiding. They are related to Photonic crystals because of their large enough refraction difference indexes (n 2 - n 1 ) that makes unavoidable to consider in full the reflected wave, well beyond the approximations required for analytical gap solitons. Effectively, their confining capabilities are or primary importance, however, the potential of those structures are substantial and deserves to be further explored. Waveguiding occurs where the structure is homogenous, and may be handled on well known methods. Nonlinear propagation has been observed on solid core Bragg fibers and the soliton distribution on a nonlinear circular and annular region have been described [1]. Linear Photonic annular structures, such as resonators, have been studied by A. Yariv [2] as well as on omniguide fibers. The propagation along the direction where the material is inhomogenous, and that correspond to the beam profile, is a complex task and it is the objective of this paper.

CQED has been an active field of research for the last three decades, describing the intimacy of the interaction of radiation and matter in small volumes λ3, and have demonstrated that modifies not only the nature of this interaction, but also atomic characteristic that often were thought intrinsic, such as spontaneous emission or the very quantum nature of the interaction. These conditions have acquired quite an importance for the current activity on Quantum computation and Information. However, most of that activity has been developed in the conceptual and experimental framework of atomic systems. There is evidence that such features also occurs in Quantum Dots. We compare the Dicke and Jaynes Cummings dynamics of atoms described by the Hamiltonian of Quantum Dots, and develop the SU(2) perturbative approach in the regimen where the excitation number (atoms + photons) is larger than the number of atoms L. We exhibit the dynamical detuning produced by the Forster interaction.

E. Gonza1ezRamirezl*, J D. Cluckie1, M. Tecpoyotl-Torres2, M. A. Rico-Ramirez', G. Cerda-Villafafla1 J Escobedo-Alatorre2 and J. Sanchez-Mondragon31Water and Environmental Management Research Centre (WEMRC), Department of CivilEngineering, University ofBristol, Lunsford House, Cantocks Close, Bristol BS8 1UP;2Research Center ofApplied Sciences and Engineering (CIICAp), Autonomous University ofMorelos State (UAEM); Av. Universidad No. 1001, C. P. 62210,Cuemavaca, Mor., Mexico;3National Institute for Astrophysics, Optics and Electronics (INAOE),P.O. 51 & 216, Z.P. 72000, Puebla, Mexico.ABSTRACT

An analysis of out-coupling in a laser shows an optimum way of subtracting more output power by choosing an appropriate cavity arrangement from a high-power fiber laser. This investigation consisted in resolving analytically the effect of different cavities in our laser system and one thing that outcome was to know that a fiber laser can operate with high efficiency even with high losses in one end of the cavity (e.g. at an external diffraction grating), only if the feedback in the out-coupling end is low. Moreover, it was also found that is possible to improve the output power by reducing the feedback in the out-coupling end. Parameters considered in this resolved method are 0.1 NA, 10 μm diameter core, 200 μm inner-cladding diameter and 10 dB small-signal absorption. The fiber laser was doped with ytterbium and lases at 1080 nm, when pumped at 915 hm. The maximum pump power was set to 10 W.

We propose a new structure for an integrated variable optical attenuator using InGaAsP multiple quantum wells. The principle of operation relies on the self-imaging properties of multimode interference (MMI) waveguides. The device consists of a MMI region that is 12 μm wide by 350 μm long, with input and output waveguides that are 2 μm wide. The dimensions of the MMI are calculated such that an image of the input field is produced at the output waveguide. The last statement is true as long as the phase relation between the modes in the MMI section is kept constant. Therefore, by selectively perturbing the refractive index within the MMI section, the phase relation of the modes is altered, thereby modifying the interference properties at the output of the device. We present numerical simulations using the Finite-Difference Beam Propagation Method (FD-BPM), and demonstrate that optical attenuation is possible by selectively modulating the refractive index of a narrow region within the MMI section. A dynamic range of -37 dB can be easily obtained at a wavelength of 1.55 μm with a device insertion loss of 0.3 dB. The effects of electro-absorption on the device performance are also investigated.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We present experimental results that show the possibility of use an All-fiber Sagnac interferometer to compensate the transmitted spectrum of an optical signal. The compensation is achieved by selecting a wavelength and twisting both arms of the interferometer for that fixed wavelengths. We present a theoretical model that explain such behavior.

We present a numerical study of the reflection of one-dimensional spatial solitons at non-linear interface between a photorefractive medium and a linear medium. In this work, we have considered that non-linear medium is governed by both;drift and diffusion mechanisms. Our study places emphasis on determining the physical conditions under which the beamreflected is still a spatial soliton. The beam is deflected into the interface using the self-bending effect. Introduction Photorefractive crystals (PRC) provided some amazing nonlinear features for low powers light beams. Almost 7 years ago,the first interaction between one-dimensional spatial solitons and PRC was experimentally showed by Duree' et. al. andIturbe2 et. al. for different types of non-linearity. After this, several effects related with solitons in PRC have been studied inorder to develop ultra-fast commuters and optical logic gates3. In the same way, reflection effect of beam light in twodifferent media, when at least one of the media exhibits some kind of optical nonlinearity4 (Kerr, saturable, quadratic, etc.),has been extensively studied5 Recently, Alvarado6 et. al. determined the physical condition under which a spatial soliton isobtained after reflection by an interface non-linear-linear.In this paper we analyze, from numerical and the theoretical point of view, the behavior of one-dimensional brightspatial soliton in a PRC governed by both non-linearities; drift and diffusion, as it reaches the boundary whit a linear mediumusing self-bending effect7.

In this work we discuss the possibility of using an optical fiber laser constructed by two Bragg grating as a temperature sensor. The device is based on measurement of the power transmitted through the Bragg gratings when the temperature of one of these gratings is changed. Changes on the temperature results in a shift of reflection wavelength of the Bragg grating and therefore change the transition coefficient. The resulting change of the power at the laser output can be used for simple and exact measurement of the temperature.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We have developed a program for phase shift measurement on fringes pattern. Our program has capability to measure displacement of vertical fringes, tilted, curvy, and circular fringes, because of the use of pattern correlation.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The fiber ioop mirror constructed from a low-birefringent twisted fiber was numerically examined. The non-linearellipse rotation effect have been included in the consideration. We have shown, that in this configuration the non-linear variation of the transmission coefficient is possible even with a 0.5/0.5 coupler. By appropriate choice of thefiber twist, birefringence, and length, variety of different characteristics of the interferometer can be achieved. Someof the configurations manifest polarization independent operation. 1. INTRODUCTION In the basic non-linear optical loop mirror (NOLM)1 unequally split counter-propagating beams polarized in parallel induce different phase shifts by the self-phase modulation effect. Such an interferometer operates as a non-linearmirror with high reflectivity at low-intensity. Among them are devices in which the counter propagating beams arenot polarized in parallel and their state of the polarization differs from lineal. In such NOLM the non-linear ellipserotation effect can be expected when low-birefringent fibers are used. This effect and its applications have beendiscussed intensively for fibers without twist, and for twisted fibers.2 The possible impact of the non-linear ellipserotation effect on the NOLM operation has been mentioned shortly in ref.

Recent developments in the construction of Erbium-doped fibers have seen parallel progress in the measurement techniques to characterize these fibers. In this paper, we discuss a simple method of obtaining threshold power amplification of Erbium-doped fibers. The method can be used to measure the threshold power of this particular fiber. As a result, the predicted threshold power value is in very good agreement with the experimental results obtained. We have based our measurements of the amplified spontaneous emission on both the forward and the backward directions of the fiber axis. We also report on other parameters such as Erbium doping concentration, the spectrum of absorption, and cross sections, with the objective of obtaining data for comparison of predicted threshold amplification with actual threshold amplification, when the Erbium-doped fibers are used in laser systems.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We present the resonance fluorescence spectrum produced by a partially coherent external field, described by its even order correlation. We discuss CW [1] partial coherence but the procedure is suitable for pulse excitation beams where most of recent experimental interest has arised. In our analysis we consider an stochastic driving field and the semiclassical theory of radiation in a two level atom[2].

We present a theoretical and experimental analysis of the Z-scan technique in thick media with thermal nonlinearity in steady-state regime. The theoretical model considers the thick medium as a stack of thin thermal lenses. Numerical solution for the Z-scan technique is obtained. Experimental results for the technique using a sample of methylene blue in a solvent under cw illumination from a 10 mW He-Ne laser beam are obtained. Comparison of the experimental and theoretical results is made. Good agreement between theory and experiment is obtained.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Analytical results of the stimulated Raman self-scattering influence on the propagation of femtosecond optical solitons are presented. The spectral perturbation method is developed, and we show that this method allows us to obtain a quantitative estimation of the frequency shift for an arbitrary relation between the parameters of the soliton pulse and the Raman line.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Analytical expression for the possible oscillation frequencies generated by a single-mode linear-cavity fiber laser are presented. The mathematical model takes into account dispersion and nonlinear self-phase modulation.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.