Search results for "Single-mode optical fiber"
showing 10 items of 87 documents
All-optical simultaneous polarization attraction and intensity regeneration of a 40-Gbit/s RZ signal
2011
We experimentally report the dual all-optical instantaneous regeneration of both the state of polarization and the intensity profile of a 40 Gbit/s Return-to-Zero telecommunication signal by means of a unique segment fiber.
Structural similarities and differences among attractors and their intensity maps in the laser-Lorenz model
1995
Abstract Numerical studies of the laser-Lorenz model using parameters reasonably accessible for recent experiments with a single mode homogeneously broadened laser demonstrate that the form of the return map of successive peak values of the intensity changes from a sharply cusped map in resonance to a map with a smoothly rounded maximum as the laser is detuned into the period doubling regime. This transformation appears to be related to the disappearance (with detuning) of the heteroclinic structural basis for the stable manifold which exists in resonance. This is in contrast to the evidence reported by Tang and Weiss (Phys. Rev. A 49 (1994) 1296) of a cusped map for both the period doublin…
A new method to measure the wavelength of single-mode pulsed lasers with a scanning Michelson interferometer
1994
We report on the possibility to measure the wave-lengths of pulsed single-mode lasers by means of a two-beam Michelson interferometer in motion [1,2]. The corner reflector moves with a nearly constant speed creating a path differenceL so thatL/C ≪ 1/Δν, Δν being the spectral width of the laser to be measured. The reference laser is a stabilized He-Ne (Spectra-Physics, model 117 A) to a precision of the order of two parts in 109. The fringe pattern of the two beams (reference beam and measured beam) is sampled simultaneously with a repetition rate of 40 ms. With this new method, the frequency doubled injection-seeded Nd: YAG laser wavelength has been measured with an accuracy of the order of…
Characterization of single-mode graded-index fibers: A new method based on transverse offset splice loss
1994
A method of characterization has been proposed for single-mode graded-index fibers using knowledge of the power transmission coefficient at the splice as a function of transverse offset. The method utilizes an analytical expression for the power transmission coefficient based on a highly accurate variational approximation for the LP01 mode developed earlier. The method accurately predicts the profile shape parameter and the normalized frequency of the fiber. © 1994 John Wiley & Sons, Inc.
Conditional generation of non-classical states in a nondegenerate two-photon micromaser: single-mode Fock states preparation. II
1997
Abstract A conditional generation of single-mode Fock states in the framework of a non-degenerate two-photon micromaser theory is reported. The exact expression for the probability of success of the experiment is obtained. We show that it is possible to conjugate experimentally interesting values of this probability, with the generation of number states having a controllable high intensity. This objective is reached by constructing analytically detailed rules about the cavity state at t = 0 as well as the atom–field interaction times as functions of the available operating conditions. These rules play a central role in our Fock-state-building process, leading to an essential countering of t…
Backaction-evading measurement of entanglement in optomechanics
2019
We propose here a fully backaction-evading scheme for the measurement of the entanglement between two nanomechanical resonators. The system, which consists of two mechanical oscillators, coupled to a single mode of an electromagnetic resonant cavity through a radiation-pressure interaction term, is driven by two pump tones and four detection tones. As previously discussed in the literature, the former induce entanglement between the two mechanical oscillators, while we show here that a specific choice of phase and amplitude of the detection tones allows for direct pairwise reconstruction of the collective quadrature fluctuations of the mechanical oscillators belonging to quantum-mechanics-f…
Steady-state emission and stability of a single-mode two-level Fabry-Perot cavity laser
1997
Abstract An analytical steady-state solution for a single-mode homogeneously-broadened two-level Fabry-Perot laser, valid for any field intensity, cavity detuning and level-population decay rates, is obtained. A power-series expansion of this solution allows to perform a linear stability analysis which reveals the existence of two Hopf bifurcations instead of one as in unidirectional ring lasers. These bifurcations delimit the domain of unstable emission of the laser with respect to small perturbations. The instability threshold for hard-mode excitation is higher than in a ring laser, although introduction of a small definite detuning makes them similar. The time-dependent behaviour above t…
Stability of gyrotron operation in very high-order modes
2012
This study was motivated by the desire to increase the power, which can be delivered by gyrotrons in long pulse and continuous regimes. Since the admissible power level is determined by the density of ohmic losses in resonator walls, to increase the radiated power a gyrotron should operate in higher order modes. Using an existing gyrotron developed for plasma experiments in the International Thermonuclear Experimental Reactor as a base model, the stability of operation of such a gyrotron in modes with larger number of radial variations was studied. It is shown that the power level achievable in such gyrotrons in stable single mode regimes is close to 1.5 MW. The power level 1.7–1.8 MW can b…
Spatial and spectral nonlinear shaping of multimode waves
2016
We demonstrate a novel nonlinear dynamics of multimode fibers that reshapes their spectral and spatial beam profiles, based on spatiotemporal modulation instability. Sidebands ranging from the visible to the near-infrared are carried by one and the same spatial bell-shaped profile.
High repetition rates and high quality optical pulse train generator based on solitons over finite background
2013
This work proposes to fully exploit the nonlinear evolution undergone by a sinusoidal modulation with a finite background propagating along an optical fiber. For the original method to overcome this major drawback is to exploit the π phase shift that exists between the pulsed part and the background. By using a simple delay-line interferometer, it is possible to simultaneously double the repetition rate of the pulse train and to annihilate the deleterious background by imprinting a controlled π phase shift.