RESUMEN

In light of the widespread use of high-energy lasers (HELs) for a variety of purposes, for example, standoff (>100 m) applications, will require the ability to monitor in real time the interaction with processed materials. While multiple sensing methods have been successfully developed for industrial HEL systems operating at close range, they are not compatible with the unique requirements of long-distance applications. Here, high-energy laser-induced oxidation spectroscopy (HELIOS) is demonstrated on carbon steel coupons as an efficient standoff assessment method compatible with long distance HEL applications. Acute monitoring of spectral features from thermally excited iron atoms and oxides, corroborated with real-time temperature measurements, reveals the interaction mechanisms at play.

RESUMEN

The damage threshold of silicon-based cameras to laser irradiation is measured for continuous wave lasers at both in-band and out-of-band wavelengths. Clarifications about the various kinds of damage reported in the literature are also presented and explained through various tests. For increasing laser intensities, the sequence of laser effects on cameras usually starts from dazzling, to a decrease of the pixel response up to the complete neutralization of its pixel matrix. However, the intensity range for the complete sequence of these laser effects can strongly depend on the laser wavelengths and the tested cameras, particularly for out-of-band laser wavelengths. The proposed definitions of damage thresholds presented in this work offer a basis for the future comparison of results between different studies.

RESUMEN

We directly investigate both experimentally and numerically the influence of optical nonlinear loss dynamics on a silicon waveguide based all-optical device. The dynamics of these nonlinear losses are explored through the analysis of optical limiting of an amplitude distorted 10 Gbit/s signal in a slow-light silicon photonic crystal waveguide. As the frequency of the distortion approaches the free-carrier recombination rate, free-carrier absorption reaches a steady state, leaving two-photon absorption the dominant dynamic nonlinear loss. Our results highlight the importance of engineering the free-carrier lifetime in silicon waveguides for high speed all-optical processing applications.

RESUMEN

We demonstrate a soliton fiber laser based on an anomalously dispersive erbium-doped fiber butt-coupled to a saturable absorber mirror for passive mode locking. The laser generates 180 fs pulses at a repetition rate of 491 MHz and exhibits a timing jitter as low as 20 fs over the frequency range 1 kHz-10 MHz.

RESUMEN

We assess the scaling potential of high repetition rate, passively mode-locked erbium-doped soliton lasers. Our analysis focuses on three recently demonstrated lasers using saturable Bragg reflectors (SBR) as the mode-locking element. We use the soliton Area theorem to establish the limitations to increasing the repetition rate based on insufficient intracavity pulse energy, SBR properties, and dispersion engineering. Finally, we examine possible approaches to alleviate these limitations by changing the laser's structure and composition.

Asunto(s)

Láseres de Estado Sólido , Modelos Teóricos , Simulación por Computador , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Reproducibilidad de los Resultados , Sensibilidad y Especificidad

RESUMEN

We present a simple way to analytically predict the effect of the temporal Talbot self-imaging process on random amplitude noise and timing jitter in periodic optical pulse trains. The analysis is general and can be applied to any pulse shape; simulation results are in excellent agreement with the predicted values. In addition, the results clearly show that the temporal Talbot effect has an inherent property of mitigating the standard deviation of both pulse amplitude noise and timing jitter.

RESUMEN

We report the first demonstration of long period gratings in single mode As(2)Se(3) chalcogenide glass fiber. The grating is implemented by pressing a threaded rod against a short piece of fiber. Its strength can be tuned over a 25 dB range, has high repeatability, and is fully reversible.