In this paper, we present a novel Brillouin fiber-ring laser utilizing an unbalanced Mach–Zehnder interferometer (UMZI) as coupling device. The laser is pumped by a distributed-feedback laser diode and shows continuous-wave and single-frequency operation. Frequency-dependent transmission characteristics of the UMZI make it possible for the pump wave to pass through the laser-ring cavity with no...

We demonstrate a single-spacing, multi-wavelength Brillouin-Raman fiber laser utilizing an enhanced cavity of nonlinear amplifying loop mirror. In this structure, the optimization of multi-wavelength lasing is done with proper adjustments of coupling ratio and Brillouin pump power. When setting the Raman pump power to 300 mW, up to 28 channels with an average 17 dB optical signal-to-noise ratio...

Quasilongitudinal sound velocities and the second-order elastic moduli of tetragonal hen egg-white lysozyme crystals were determined as a function of relative humidity (RH) by Brillouin scattering. In hydrated crystals the measured sound velocities in the [110] plane vary between 2.12 +/- 0.03 km/s along the [001] direction and 2.31 +/- 0.08 km/s along the [110] direction. Dehydration from 98% ...

A thorough analysis of the key factors impacting on the performance of Brillouin distributed optical fiber sensors is presented. An analytical expression is derived to estimate the error on the determination of the Brillouin peak gain frequency, based for the first time on real experimental conditions. This expression is experimentally validated, and describes how this frequency uncertainty dep...

On Brillouin Scattering in Dense Fluids It has been shown analytically that Mountain 's theory of the spectral distribution of density fluctuations in fluids having an external degree of f reedom (MOUXI) is equivalent to the translational hydrodynamics theory (TH) of Desai and Kapral at liquid state densities where selfdiffusion can be neglected. On the other hand, comparing TH and Mountain's s...

A simple analytical treatment based on the hydrodynamical model of plasmas is developed to study both steady-state and transient stimulated Raman and Brillouin scattering processes in centrosymmetric or weakly noncentrosymmetric semiconductors. Gain constants, threshold-pump intensities, and optimum pulse durations for the onset of Raman and Brillouin instabilities are estimated. The qualitativ...

We present, to the best of our knowledge, the first demonstration of a narrow linewidth, waveguide-based Brillouin laser that is enabled by large Brillouin gain of a chalcogenide chip. The waveguides are equipped with vertical tapers for low-loss coupling. Due to optical feedback for the Stokes wave, the lasing threshold is reduced to 360 mW, which is five times lower than the calculated single...

Spontaneous Brillouin backscattering, which accompanies the operation of Brillouin dynamic gratings (BDGs) setups, is investigated both theoretically and experimentally. It is shown that this noisy emission, which cannot be separated from the signal of interest, contains not only the probe spontaneous Brillouin backscattering but also a significant contribution from the spontaneous/stimulated a...

We have experimentally studied the effects of gamma-radiation up to very high total doses on the physical properties of Brillouin scattering in standard commercially available optical fibres. A frequency variation of about 5 MHz for both Brillouin frequency and linewidth has been measured at the total dose of about 10 MGy. The radiation-induced shift has a negligible practical impact and makes ...

where the transformation or supercell matrix M is nonsingular with integer components, which implies that the SC is commensurate to the pc. The determinant of M is the multiplicity N of the SC, i.e. the ratio of the respective volumes VSC/vpc. The hexagonal pc and orthorhombic SC of the two-dimensional honeycomb net is depicted in figure A.1a. In reciprocal space, there are consequently two dis...