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In a two-stage phosphosilicate Raman fiber laser (1.26/1.53μm) pumped by Yb-fiber laser (1.08μm), a temperature tuning of FBGs forming Raman cavities has been performed by means of thermoelectric modules based on Peltier elements. Output power and spectral profiles at 1.26μm and 1.53μm have been monitored during such T 0 -tuning in the range of ±25C corresponding to the FBG wavelength shift of ±0.2nm. The most pronounced effect is that the observed spectral profile at 1.26μm corresponding to the first-stage highly-reflective cavity consists of two splitting components, which become strongly asymmetric while independent T0 -tuning of cavity FBGs. A simple model considering spectral broadening with increasing pump power and T0 -induced shift between central wavelengths of the FBGs has been developed. The model takes into account wavelength-dependent Raman gain saturation and qualitatively describes the observed effects of the splitting and asymmetry with T0 -tuning. It is also demonstrated, that the studied spectral broadening and shift lead to the effective "bleaching" of the highly-reflective cavity, so estimated integral transmission may increase by order of magnitude from minimum transmission ~ 1%, corresponding to central FBG wavelength.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Uv system of high output power and large coherence length operating at 244 and 257nm is described. Single-frequency argon laser output is frequency-doubled by BBO crystal placed in external resonant cavity. Applications of the system for fiber grating fabrication are discussed. System for characterization of fiber gratings based on the optical spectrum analyzer is described. Technique of temperature tuning of FBGs forming a cavity of a fiber Raman laser is applied that provides high sensitivity of Raman laser output power and spectra to a temperature difference of the cavity FBGs. Possible applications of such scheme in fiber sensing are discussed.

Artificial laser guide star (LGS) is usually created by excitation of sodium atoms in the natural layer at 90 km with a yellow laser beam at 589.2 nm. Such a spot-like source is used for guiding the adaptive optics system of telescopes, that allows to improve greatly the quality of images of real astronomic objects by correcting the wavefront distortions induced by atmospheric turbulence. In frames of ALFA project a single-frequency yellow source of 3-4 W output power has been developed and is already used for LGS excitation. In this paper we report on the pump laser for dye amplifier developed for the Max Planck Institute of Extraterrestrial Physics in Garching, Germany, that will be applied for substantial enhancement of the output power in the system. The developed argon laser provides high angular stability and beam quality by means of active cavity alignment at 70 W output level, that has no analogues. Basic principles and device design are described.

Continuous-wave generation is demonstrated of the anti- Stokes Raman laser in new (Alpha) scheme ArII 3d'2G9/2 yields 4p'2F7/2 yields 4s'2D5/2 with long- lived start and final levels. Red pump radiation with wavelength (lambda) p equals 611 nm from a dye laser that excites transition 3d'2G9/2 yields 4p'2F7/2 is converted into the blue radiation at (lambda) equals 461 nm (4p'2F7/2 yields 4s'2D5/2) with efficiency of about 30%. The tunability range spans more than +/- 10 GHz around exact resonance, which is five times as wide as the Doppler contour. The output frequency (omega) is found to depend linearly on the frequency (omega) p of the pump field: (omega) approximately equals (omega) p(lambda) p/(lambda) . A sharp peak of output power is observed in the detuning curve at the exact resonance instead of well-known two-photon dip. The model is proposed that includes ionic scattering in plasma and interaction of the running pump and standing output waves. The derived formula offers an interpretation of the observed peak.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.