The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform

Dieter Bimberg - One of the best experts on this subject based on the ideXlab platform.

  • 1.3 µm Range 40 GHz quantum-dot mode-locked laser under external continuous wave light injection or optical feedback
    Semiconductor Science and Technology, 2010
    Co-Authors: Gerrit Fiol, Moritz Kleinert, Dejan Arsenijević, Dieter Bimberg
    Abstract:

    We have investigated the jitter, repetition frequency and spectra of a quantum-dot mode-locked laser operating at 40 GHz under continuous wave external light injection using an external cavity laser or under optical feedback. For the case of the continuous wave light injection we realized a shift of the optical emission of up to 15 nm. With optical feedback we have found a ninefold jitter reduction, down to a record low value of 1 ps over an Integration Range from 10 kHz to 1 GHz. Optical feedback fixes the repetition frequency while changing current and voltage applied to the diode. This is due to the fact that stable mode locking occurs at frequencies which are integers of the feedback loop frequency.

Jacques Parent Du Châtelet - One of the best experts on this subject based on the ideXlab platform.

  • Links Between Weather Phenomena and Characteristics of Refractivity Measured by Precipitation Radar
    Boundary-Layer Meteorology, 2012
    Co-Authors: Lucas Besson, Chiraz Boudjabi, Olivier Caumont, Jacques Parent Du Châtelet
    Abstract:

    Refractivity depends on meteorological parameters such as temperature and water vapour pressure and can be measured using a weather radar. A realistic atmospheric simulation from the Meso-NH numerical model is used in order to describe and establish the relation between refractivity and the dynamic and thermodynamic phenomena responsible for the development and propagation of convection. These investigations lead to discussion of the complementarity between the refractivity and the convective available potential energy. The relation observed between the refractivity signal and the meteorological parameters calls the refractivity measurement into question, since it is based on phase differentiation with time and space and can be degraded by phase aliasing problems. These aliasing problems increase with the radar frequency (perceptible in the S-band, serious in the C-band, and more serious in the X-band) and also with the Integration Range and sampling time. Thus, a statistical approach permits us to simulate the possibility of measuring the refractivity with operational radar during convective events. A typical case in the south-east region of France is selected to simulate measurements by radar (S-band, C-band, X-band) in convective systems, in order to evaluate the measurement feasibility, particularly in terms of phase ambiguity, related to temporal and spatial sampling, of a future implementation of the refractivity measurement over the French operational radar network. This numerical statistical approach is completed with a similar study using in-situ measurements performed at the Trappes station. The seasonal and diurnal dependencies of aliasing are investigated, leading to clarification of the impact of the turbulent fluxes on the refractivity measurement.

Robert J. Manning - One of the best experts on this subject based on the ideXlab platform.

  • Self-starting optical-electrical-optical homodyne clock recovery for phase-modulated signals.
    Optics letters, 2017
    Co-Authors: Ehsan Sooudi, Andrew D. Ellis, Robert J. Manning
    Abstract:

    We propose a novel self-homodyne optical–electrical–optical clock recovery technique for binary phase-shift keying (BPSK) signals using commercial optical and electrical components. We present the principle of operation as well as a proof-of-concept experiment for a 10.7 Gb/s BPSK signal clock recovery transmitted over a dispersion-compensated link of 20 km of single-mode fiber. Suppression of pattern-related frequency noise at the output of the recovered clock is shown. The timing jitter of the recovered clock at 10.7 GHz was measured to be ∼450  fs (Integration Range: 100 Hz–10 MHz).

D. V. Griffiths - One of the best experts on this subject based on the ideXlab platform.

  • Generalized numerical Integration of moments
    International Journal for Numerical Methods in Engineering, 1991
    Co-Authors: D. V. Griffiths
    Abstract:

    Sampling points and weighting coefficients of the Gaussian type are presented for integrands typically encountered in axisymmetric finite elements. The proposed method is a generalization of Gaussian Integration of Moments for non-zero limits of Integration. The method achieves one extra order of accuracy in the Integration of polynomials as compared with the Gauss-Legendre method with the same number of sampling points. Although the locations of sampling points require the solution of non-linear equations, analytical solutions are presented for the cases of one and two sampling points. Special cases of these general expressions are shown to include both Gauss-Legendre Integration corresponding to an Integration Range at a considerable distance from the axis of symmetry, and Fishman Integration corresponding to an Integration Range whose lower limit lies on the axis of symmetry.

Gerrit Fiol - One of the best experts on this subject based on the ideXlab platform.

  • 1.3 µm Range 40 GHz quantum-dot mode-locked laser under external continuous wave light injection or optical feedback
    Semiconductor Science and Technology, 2010
    Co-Authors: Gerrit Fiol, Moritz Kleinert, Dejan Arsenijević, Dieter Bimberg
    Abstract:

    We have investigated the jitter, repetition frequency and spectra of a quantum-dot mode-locked laser operating at 40 GHz under continuous wave external light injection using an external cavity laser or under optical feedback. For the case of the continuous wave light injection we realized a shift of the optical emission of up to 15 nm. With optical feedback we have found a ninefold jitter reduction, down to a record low value of 1 ps over an Integration Range from 10 kHz to 1 GHz. Optical feedback fixes the repetition frequency while changing current and voltage applied to the diode. This is due to the fact that stable mode locking occurs at frequencies which are integers of the feedback loop frequency.