796 research outputs found
Soliton propagation and polarisation mode-locking in birefringent optical fibres
Soliton propagation in polarization-preserving fibres is analysed. Based on the coupled nonlinear Schrodinger equations we derive an analytical approximation for such type of soliton propagation. Exploitation of soliton polarization properties for passive mode-locking in fibre lasers is also considered
Thermal instability of a compound resonator
We investigate the thermal and Kerr nonlinearity in a system of two optically-coupled silica microtoroid resonators experimentally and theoretically. A model for two coupled oscillators describing nonlinear resonance curves is developed. Stability of the static solutions is analyzed. It is shown that thermal nonlinearity is responsible for driving the eigenfrequencies of the two resonators apart, making the normal modes of the system unstable as the pump power grows. The red-detuned normal mode becomes unstable for certain pumping powers
Fundamental thermal fluctuations in microspheres
We present a theoretical analysis and the results of measurements of thermorefractive noise in microcavities. These measurements may be considered direct observations of fundamental fluctuations of temperature in solid media. Our experimentally measured noise spectra are in agreement with our theoretical model
Generation of optical frequency combs with a CaF2 resonator
We demonstrate optical frequency combs using the fluorite whispering gallery mode resonator as a nonlinear Kerr medium. Two regimes of generation are observed, giving the record low repetition rate of 13 GHz, equal to the cavity's free spectral range (FSR) or high repetition rates of multiples of cavity FSR. An intermediate regime was also observed. Raman lasing spectrum similar to modulation instability in fibers was observed for the first time to the best of our knowledge
Compact 85 fs frequency doubled 810 nm fiber system with 60 mW of average power
We demonstrate a sub-100 fs frequency doubled fiber laser operating at 810 nm. The laser produces 60 mW of average power at a repetition rate of 50 MHz. Extremely low amplitude noise (below 0.1%) and compact size makes this source ideal replacement for low power ultrafast Ti:Spphire lasers
Compensation of thermal nonlinearity effect in optical resonators
Thermal nonlinearity is known to cause bistability in Whispering Gallery Mode (WGM) resonators and to destabilize the red slope of the Lorentzian resonant curve. We demonstrate an optical technique that allows compensation of the thermal effect and forces the resonances to appear linear with both red and blue slopes stable
Finite element modeling of coupled optical microdisk resonators for displacement sensing
We analyze normal mode splitting in a pair of vertically coupled microdisk
resonators. A full vectorial finite element model is used to find the eigen
frequencies of the symmetric and antisymmetric composite modes as a function of
coupling distance. We find that the coupled microdisks can compete with the
best Fabry-Perot resonators in displacement sensing. We also show how we
configured FreeFem++ for the sphere eigenvalue problem.Comment: 10 pages, 4 figures, 1 FreeFem++ script (download and unzip the paper
source
- …