ABSTRACT
An optical wave equation for scattered light in materials with macroscopic spatial inhomogeneities is presented and analyzed. The equation is applicable to a variety of linear and nonlinear optical interactions in media with intrinsic, induced, or engineered inhomegeneities. While it is valid regardless of the spatial scale of these inhomogeneities, the strongest effect is expected from inhomogeneities of a subwavelength scale size typical for nanostructured optical media.
ABSTRACT
We propose and investigate an accurate method for the experimental measurement of the stimulated Brillouin scattering gain coefficient in optical fiber. The gain is extracted from measuring the transmitted pump power at the threshold of stimulated Brillouin scattering (SBS) laser oscillation in a Fabry-Perot cavity formed by Fresnel reflection at the fiber ends. The method is free from a range of uncertainties and difficulties of commonly used approaches and is easy to implement. Experimental evidence of the variation of the SBS gain coefficient with numerical aperture of the fiber, first predicted in [Phys. Rev. Lett. 85, 1879 (2000)], is proven.
ABSTRACT
Temporally stable high-fidelity optical phase conjugation by stimulated Brillouin scattering of cw laser radiation is achieved in multimode silica fiber with cavity feedback. A power threshold of approximately 500 mW and a reflectivity of 70% were obtained in a 340-m-long fiber with a cw Nd:YAG laser.
ABSTRACT
We report results on the appearance of temporally stable Stokes emission in stimulated Brillouin scattering (SBS) excited by continuous-wave pump radiation in optical fiber. With increasing pump strength the stable component emerges from stochastic emission slightly above the SBS threshold to become the dominant contribution, independent of fiber characteristics. These findings are shown to be a manifestation of spectral self-phase conjugation, providing what is to our knowledge the first experimental evidence of this phenomenon in optics.
ABSTRACT
A master oscillator power amplifier system comprising a cw Nd:YAG master oscillator, a quasi-cw diode-pumped power amplifier, and a fiber-based stimulated Brillouin scattering phase-conjugate mirror is reported. A 12-pass amplifier configuration is employed to achieve high gain in a small-length slab amplifier. Residual and pump-induced optical inhomogeneities in the slab are corrected by the fiber phase conjugator to achieve diffraction-limited output beam quality. 300 W quasi-cw output and a maximal attainable gain of approximately 150 for the system are obtained.
ABSTRACT
We experimentally show that, when stimulated Brillouin scattering is generated in optical fiber by use of monochromatic cw pump radiation, the transmitted pump radiation exhibits spectral broadening that is much narrower than the classical homogeneous gain-narrowed Brillouin bandwidth. The bandwidth is practically independent of the pump strength, fiber characteristics, and the waveguide-induced inhomogeneously broadened bandwidth of the Stokes emission. We show that these properties arise from strong parametric coupling of the Stokes and pump signals in the pump-depletion region.
ABSTRACT
We provide direct experimental evidence of waveguide-induced inhomogeneous spectral broadening of stimulated Brillouin scattering (SBS) in optical fiber. It is shown that the SBS spectral width and gain depend on the numerical aperture for both single-mode and multimode fibers, the functional dependencies of which are in good agreement with our model description of the phenomenon.
