We report on a 2.3 m long air-clad ytterbium-doped large-mode-area photonic crystal fiber laser generating up to 80 W output power with a slope efficiency of 78%. Single transverse mode operation is ...achieved with a mode-field area of 350 /spl mu/m/sup 2/. No thermo-optical limitations are observed at the extracted /spl sim/35 W/m, therefore such fibers allow scaling to even higher powers.
We report on the design of a single-polarization single-transverse mode large mode area photonic crystal fiber. By including index-matched stress applying elements in the photonic cladding an ...ultra-broadband single polarization window is obtained while a large mode field area of ~700 microm(2) is maintained. Based on that design, an Yb-doped double-clad photonic crystal fiber is realized that combines low nonlinearity and single polarization properties. A first result of the high power operation using this fiber is demonstrated.
We numerically investigate the formation of soliton pairs (bound states) in mode-locked fiber ring lasers in the
normal
dispersion domain. In the distributed mathematical model (complex cubic-quintic ...Ginzburg–Landau equation), we observe a discrete family of soliton pairs with equidistantly increasing peak separation. We show that stabilization of previously unstable bound states can be achieved when the finite relaxation time of the saturable absorber is taken into account. The domain of stability can be controlled by varying this relaxation time. Furthermore, we investigate the parameter domain where the region of stable bound states does not shrink to zero for vanishing absorber recovery time corresponding to a laser with an
instantaneous
saturable absorber. For a certain domain of the small-signal gain, we obtain a robust first level bound state with almost constant separation where the phase of the two pulses evolves independently. Moreover, their phase difference can evolve either periodically or chaotically depending on the small signal gain. Interestingly, higher level bound states exhibit a fundamentally different dynamics. They represent oscillating solutions with a phase difference alternating between zero and
π
.
We propose a novel photonic crystal waveguide design with defects at the termination to provoke directional emission. Because the resulting optical field distribution at the waveguide exit resembles ...a triple point source, the light can emit with low angular divergence. This phenomenon appears both in photonic crystal structures formed by dielectric rods as well as by air holes.
We calculate three-dimensional (3D) dispersion relations of woodpile and inverse opal photonic crystals. Inspecting the iso-frequency surfaces of the four lowest-order bands at appropriate ...frequencies we identify regions where self-collimation of light may be expected. These predictions are verified by means of finite-difference time-domain calculations both for high- and low-index photonic crystals.
In this paper, the properties of chirped photonic crystal fibers for guiding sub-100-fs pulses are discussed by numerical simulations and approximate analytical considerations. The nearly ...distortion-free guiding properties are explained by a spectral distribution of detrimental dispersive resonances. Deeper analysis reveals the geometrical properties of the innermost layer of the photonic cladding structure as a key parameter for the dispersive properties of this fiber. It is further investigated how systematic manipulation of the geometry can be exploited for influencing the guiding parameters.
We present a detailed study of the dynamics of light in passive nonlinear resonators with shallow and deep intracavity periodic modulation of the refractive index in both longitudinal and transverse ...directions of the resonator. We investigate solutions localized in the transverse direction (so-called Bloch cavity solitons) by means of envelope equations for underlying linear Bloch modes and solving Maxwell’s equations directly. Using a round-trip model for forward and backward propagating waves we review different types of Bloch cavity solitons supported by both focusing (at normal diffraction) and defocussing (at anomalous diffraction) nonlinearities in a cavity with a weak-contrast modulation of the refractive index. Moreover, we identify Bloch cavity solitons in a Kerr-nonlinear all-photonic crystal resonator solving Maxwell’s equations directly. In order to analyze the properties of Bloch cavity solitons and to obtain analytical access we develop a modified mean-field model and prove its validity. In particular, we demonstrate a substantial narrowing of Bloch cavity solitons near the zero-diffraction regime. Adjusting the quality factor and resonance frequencies of the resonator optimal Bloch cavity solitons in terms of width and pump energy are identified.
In this paper, we study optically parametric oscillation in a doubly resonant microsized cavity in a lithium niobate photonic crystal. Maxwell's equations are solved directly using the ...finite-difference time-domain scheme to compute stationary solutions and to obtain the bifurcation diagrams for different pump detunings. The results are compared to predictions from a mean-field approach.
We demonstrate femtosecond pulse operation of a soliton fiber laser at 1.06-mum wavelength. This laser makes use of a single piece of microstructure fiber that has been designed to simultaneously ...provide anomalous dispersion and laser gain. Using a saturable absorber mirror with deep modulation depth to initiate and sustain mode-locking, this fiber provides clean and nearly transform-limited pulses down to a pulse duration of 180 fs. To the best of our knowledge, this constitutes the first demonstration of a pure soliton fiber laser in the neodymium gain band
Remote coupling in Bragg fibers Iliew, R.; Etrich, C.; Lederer, F.
Conference on Lasers and Electro-Optics, 2004. (CLEO),
07/2004, Letnik:
2
Conference Proceeding
Recenzirano
We propose a directional coupler in Bragg fibers that allows for remote coupling and thus lossless conversion of the fundamental mode into a large-diameter annular mode. We analyze the propagation ...behavior and give design rules.
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