The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform

Heng-chia Chang - One of the best experts on this subject based on the ideXlab platform.

  • Stability Analysis of Self-Injection-Locked
    2020
    Co-Authors: Heng-chia Chang
    Abstract:

    This paper addresses the stability analysis of the Self- Injection-locked oscillators. The analysis is developed for arbitrary Self-Injection feedback loops and illustrated with the specific case of a simple time-delay cable. It is shown that the output phase sta- bility in Self-Injection-locked oscillators depends on the feedback loop delay and the types of oscillator circuits, which are repre- sented by equivalent parallel- or series-resonant oscillator models. The Self-Injection-locked technique can also be used to test the os- cillator circuit model when the Self-coupling phase is known. The theory is verified by using a Self-Injection-locked GaAs MESFET oscillator operating at -band with delay loops.

  • Stability analysis of Self-Injection-locked oscillators
    IEEE Transactions on Microwave Theory and Techniques, 2003
    Co-Authors: Heng-chia Chang
    Abstract:

    This paper addresses the stability analysis of the Self-Injection-locked oscillators. The analysis is developed for arbitrary Self-Injection feedback loops and illustrated with the specific case of a simple time-delay cable. It is shown that the output phase stability in Self-Injection-locked oscillators depends on the feedback loop delay and the types of oscillator circuits, which are represented by equivalent parallel- or series-resonant oscillator models. The Self-Injection-locked technique can also be used to test the oscillator circuit model when the Self-coupling phase is known. The theory is verified by using a Self-Injection-locked GaAs MESFET oscillator operating at X-band with delay loops.

  • Phase noise in Self-Injection-locked oscillators - theory and experiment
    IEEE Transactions on Microwave Theory and Techniques, 2003
    Co-Authors: Heng-chia Chang
    Abstract:

    Phase-noise analysis of the Self-Injection-locked oscillator is presented in this paper. The analysis is developed for different oscillator models and arbitrary Self-Injection feedback loops. The results are illustrated with specific cases of simple time-delay cable and a high-Q factor resonator. It is shown that the behavior of the phase noise is similar to an oscillator locked to an external low phase-noise source. The output phase noise can be reduced at the noise offset frequency near the carrier frequency, and returning to the free-running oscillator noise far from the carrier frequency for certain stable feedback delay ranges. The phase-noise reduction is affected by the Self-Injection signal strength and feedback transfer function for different oscillator equivalent-circuit models. The theory is verified by using a Self-Injection-locked GaAs MESFET oscillator operating at the X-band with delay cable loops. The Self-Injection-locked technique may be used to improve the phase noise of the existing oscillators.

Ling Juan Zhao - One of the best experts on this subject based on the ideXlab platform.

M Uesaka - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Self-Injection on ultraintense laser wake-field acceleration.
    Physical review. E Statistical nonlinear and soft matter physics, 2004
    Co-Authors: A Zhidkov, J Koga, K Kinoshita, M Uesaka
    Abstract:

    The Self-Injection of plasma electrons which have been accelerated to relativistic energies by a laser pulse moving with a group velocity less than the speed of light with I lambda(2)>5 x 10(19) W microm(2)/cm(2) is found via particle-in-cell simulation to be efficient for laser wake-field acceleration. When the matching condition a(0)> or =(2(1/4)omega/omega(pl))(2/3) is met, the Self-Injection, along with wave breaking, dominates monoenergetic electron acceleration yielding up to 100 MeV energies by a 100 TW, 20 fs laser pulse. In contrast to the Injection due to wave-breaking processes, Self-Injection allows suppression of production of a Maxwell distribution of accelerated particles and the extraction of a beam-quality bunch of energetic electrons.

  • Effect of Self-Injection on ultraintense laser wake-field acceleration
    Physical Review E, 2004
    Co-Authors: A Zhidkov, J Koga, K Kinoshita, M Uesaka
    Abstract:

    The Self-Injection of plasma electrons which have been accelerated to relativistic energies by a laser pulse moving with a group velocity less than the speed of light with $I{\ensuremath{\lambda}}^{2}g5\ifmmode\times\else\texttimes\fi{}{10}^{19}\mathrm{W}\ensuremath{\mu}{\mathrm{m}}^{2}/{\mathrm{cm}}^{2}$ is found via particle-in-cell simulation to be efficient for laser wake-field acceleration. When the matching condition ${a}_{0}g~{(2}^{1/4}\ensuremath{\omega}/{\ensuremath{\omega}}_{\mathrm{pl}}{)}^{2/3}$ is met, the Self-Injection, along with wave breaking, dominates monoenergetic electron acceleration yielding up to 100 MeV energies by a 100 TW, 20 fs laser pulse. In contrast to the Injection due to wave-breaking processes, Self-Injection allows suppression of production of a Maxwell distribution of accelerated particles and the extraction of a beam-quality bunch of energetic electrons.

I. A. Bilenko - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of laser stabilization via Self-Injection locking to WGM microresonator
    arXiv: Optics, 2020
    Co-Authors: Ramzil R. Galiev, N. M. Kondratiev, Valery E. Lobanov, Andrey B. Matsko, I. A. Bilenko
    Abstract:

    Self-Injection locking is a dynamic phenomenon representing stabilization of the emission frequency of an oscillator with a passive cavity enabling frequency filtered coherent feedback to the oscillator cavity. For instance, Self-Injection locking of a semiconductor laser to a high-quality-factor (high-Q) whispering gallery mode (WGM) microresonator can result in multiple orders of magnitude reduction of the laser linewidth. The phenomenon was broadly studied in experiments, but its detailed theoretical model allowing improving the stabilization performance does not exist. In this paper we develop such a theory. We introduce five parameters identifying efficiency of the Self-Injection locking in an experiment, comprising back-scattering efficiency, phase delay between the laser and the high-Q cavities, frequency detuning between the laser and the high-Q cavities, the pump coupling efficiency, the optical path length between the laser and the microresonator. Our calculations show that the laser linewidth can be improved by two orders of magnitude compared with the case of not optimal Self-Injection locking. We present recommendations on the experimental realization of the optimal Self-Injection locking regime. The theoretical model provides deeper understanding of the Self-Injection locking and benefits multiple practical applications of Self-Injection locked oscillators.

  • Numerical modelling of WGM microresonator Kerr frequency combs in Self-Injection locking regime
    Nonlinear Optics and its Applications 2020, 2020
    Co-Authors: N. M. Kondratiev, Valery E. Lobanov, A. S. Voloshin, I. A. Bilenko
    Abstract:

    We developed original model describing the process of frequency comb generation in the Self-Injection locking regime and performed numerical modelling of this process. Generation of dissipative Kerr solitons in the Self-Injection locking regime at anomalous GVD was observed and studied numerically. It was proposed that Self-Injection locking may provide easy way for generation of frequency comb at normal group velocity dispersion. This idea was investigated in detail and platicon generation was demonstrated. Parameter range providing platicon excitation was found.

  • Dynamics of soliton Self-Injection locking in a photonic chip-based microresonator
    arXiv: Optics, 2019
    Co-Authors: A. S. Voloshin, N. M. Kondratiev, G. Lihachev, Tobias J. Kippenberg, I. A. Bilenko
    Abstract:

    Soliton microcombs constitute chip-scale optical frequency combs, and have the potential to impact a myriad of applications from frequency synthesis and telecommunications to astronomy. The requirement on external driving lasers has been significantly relaxed with the demonstration of soliton formation via Self-Injection locking of the pump laser to the microresonator. Yet to date, the dynamics of this process has not been fully understood. Prior models of Self-Injection locking were not able to explain sufficiently large detunings, crucial for soliton formation. Here we develop a theoretical model of Self-Injection locking to a nonlinear microresonator (nonlinear Self-Injection locking) for the first time and show that Self- and cross-phase modulation of the clockwise and counter-clockwise light enables soliton formation. Using an integrated soliton microcomb of directly detectable 30 GHz repetition rate, consisting of a DFB laser Self-Injection-locked to a Si3N4 microresonator chip, we study the soliton formation dynamics via Self-Injection locking, as well as the repetition rate evolution, experimentally. We reveal that Kerr nonlinearity in microresonator significantly modifies locking dynamics, making laser emission frequency red detuned. We propose and implement a novel technique for measurements of the nonlinear frequency tuning curve and concurrent observation of microcomb states switching in real time.

  • Self-Injection locking of a laser diode to a high-Q silicon WGM microresonator
    EPJ Web of Conferences, 2019
    Co-Authors: Artem E. Shitikov, N. M. Kondratiev, Valery E. Lobanov, Tatyana Tebeneva, O. Benderov, Alexander V. Rodin, I. A. Bilenko
    Abstract:

    The key properties of the Self-Injection locking regime of a laser diode to a high-Q microresonator with whispering gallery mode made of crystalline silicon are considered. It has been experimentally demonstrated the possibility of the Self-Injection locking using cavity made of crystalline silicon. This result opens up new possibilities for creating narrow-band highly stable laser sources in midIR, over 2.3 microns, on a new hardware base.

Markus Büscher - One of the best experts on this subject based on the ideXlab platform.

  • Electron Self-Injection threshold for the tandem-pulse laser wakefield accelerator
    Physics of Plasmas, 2020
    Co-Authors: Zahra M. Chitgar, Paul Gibbon, Jürgen Böker, Andreas Lehrach, Markus Büscher
    Abstract:

    A controllable Injection scheme is key to producing high quality laser-driven electron beams and x rays. Self-Injection is the most straightforward scheme leading to high current and peak energies but is susceptible to variations in laser parameters and target characteristics. In this work, improved control of electron Self-Injection in the nonlinear cavity regime using two laser-pulses propagating in tandem is investigated. In particular, the advantages of the tandem-pulse scheme in terms of Injection threshold, electron energy, and beam properties in a regime relevant to betatron radiation are demonstrated. Moreover, it is shown that the laser power threshold for electron Self-Injection can be reduced by up to a factor of two compared to the standard, single-pulse wakefield scheme.A controllable Injection scheme is key to producing high quality laser-driven electron beams and x rays. Self-Injection is the most straightforward scheme leading to high current and peak energies but is susceptible to variations in laser parameters and target characteristics. In this work, improved control of electron Self-Injection in the nonlinear cavity regime using two laser-pulses propagating in tandem is investigated. In particular, the advantages of the tandem-pulse scheme in terms of Injection threshold, electron energy, and beam properties in a regime relevant to betatron radiation are demonstrated. Moreover, it is shown that the laser power threshold for electron Self-Injection can be reduced by up to a factor of two compared to the standard, single-pulse wakefield scheme.

  • Electron Self-Injection threshold for the tandem-pulse laser wakefield accelerator
    arXiv: Plasma Physics, 2019
    Co-Authors: Zahra M. Chitgar, Paul Gibbon, Jürgen Böker, Andreas Lehrach, Markus Büscher
    Abstract:

    A controllable Injection scheme is key to producing high quality laser-driven electron beams and X-rays. Self-Injection is the most straightforward scheme leading to high current and peak energies, but is susceptible to variations in laser parameters and target characteristics. In this work improved control of electron Self-Injection in the nonlinear cavity regime using two laser-pulses propagating in tandem is investigated. In particular the advantages of the tandem-pulse scheme in terms of Injection threshold, electron energy and beam properties in a regime relevant to betatron radiation are demonstrated. Moreover it is shown that the laser power threshold for electron Self-Injection can be reduced by up to a factor of two compared to the standard, single-pulse wakefield scheme.