scholarly journals Dynamics of microresonator frequency comb generation: models and stability

Nanophotonics ◽  
2016 ◽  
Vol 5 (2) ◽  
pp. 231-243 ◽  
Author(s):  
Tobias Hansson ◽  
Stefan Wabnitz
Keyword(s):  
Continuous Wave ◽  
Temporal Dynamics ◽  
Frequency Comb ◽  
Modulational Instability ◽  
Theoretical Models ◽  
Light Sources ◽  
Generation Process ◽  
Modal Expansion ◽  
Frequency Combs ◽  
Comb Generation

AbstractMicroresonator frequency combs hold promise for enabling a new class of light sources that are simultaneously both broadband and coherent, and that could allow for a profusion of potential applications. In this article, we review various theoretical models for describing the temporal dynamics and formation of optical frequency combs. These models form the basis for performing numerical simulations that can be used in order to better understand the comb generation process, for example helping to identify the universal combcharacteristics and their different associated physical phenomena. Moreover, models allow for the study, design and optimization of comb properties prior to the fabrication of actual devices. We consider and derive theoretical formalisms based on the Ikeda map, the modal expansion approach, and the Lugiato-Lefever equation. We further discuss the generation of frequency combs in silicon resonators featuring multiphoton absorption and free-carrier effects. Additionally, we review comb stability properties and consider the role of modulational instability as well as of parametric instabilities due to the boundary conditions of the cavity. These instability mechanisms are the basis for comprehending the process of frequency comb formation, for identifying the different dynamical regimes and the associated dependence on the comb parameters. Finally, we also discuss the phenomena of continuous wave bi- and multistability and its relation to the observation of mode-locked cavity solitons.

scholarly journals Spectral Broadening in a Continuously Pumped Singly Resonant Second-Harmonic Cavity

2021 ◽  
Vol 11 (15) ◽  
pp. 7122
Author(s):  
Simona Mosca ◽  
Tobias Hansson ◽  
Maria Parisi
Keyword(s):  
Continuous Wave ◽  
Frequency Comb ◽  
Second Harmonic ◽  
Input Power ◽  
Second Order ◽  
Optical Frequency ◽  
Frequency Combs ◽  
Research Areas ◽  
Mixed Regime ◽  
Wide Range

Optical frequency comb synthesizers with a wide spectral range are an essential tool for many research areas such as spectroscopy, precision metrology, optical communication, and sensing. Recent studies have demonstrated the direct generation of frequency combs, via second-order processes, that are centered on two different spectral regions separated by an octave. Here, we present the capability of optical quadratic frequency combs for broad-bandwidth spectral emission in unexplored regimes. We consider comb formation under phase-matched conditions in a continuous-wave pumped singly resonant second-harmonic cavity, with large intracavity power and control of the detuning over several cavity line widths. The spectral analysis reveals quite distinctive sidebands that arise far away from the pump, singularly or in a mixed regime together with narrowband frequency combs. Notably, by increasing the input power, the optical frequency lines evolve into widely spaced frequency clusters, and at maximum power, they appear in a wavelength range spanning up to 100 nm. The obtained results demonstrate the power of second-order nonlinearities for direct comb production within a wide range of pump wavelengths.

scholarly journals Repetition frequency locking of a terahertz quantum cascade laser emitting at 4.2 THz

2020 ◽  
Vol 13 (1) ◽  
pp. 32-40
Author(s):  
Wen Guan ◽  
Ziping Li ◽  
Kang Zhou ◽  
Wenjian Wan ◽  
Xiaoyu Liao ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Continuous Wave ◽  
Frequency Comb ◽  
Signal To Noise Ratio ◽  
Phase Lock Loop ◽  
Wave Mode ◽  
Repetition Frequency ◽  
Frequency Locking ◽  
Frequency Combs ◽  
Quantum Cascade

The electrically-pumped terahertz quantum cascade laser (QCL) is characterized by high power emission, compact, broad frequency coverage, and so on, which shows abilities for frequency comb operations. Although free-running QCLs can work as frequency combs by designing the laser structure with small group velocity dispersions and/or inserting mirrors to compensate laser intrinsic dispersions, the ideal comb operation can only be obtained by firmly locking the repetition frequency and carrier frequency of a laser. In this work, we have reported a repetition frequency locking of a terahertz QCL emitting around 4.2 THz. When the 6-mm-long laser is operated in continuous wave mode without any locking techniques, the repetition frequency is measured to be ~6.15 GHz with a linewidth of hundred kilohertz. Once a phase lock loop (PLL) is applied to dynamically control the drive current of the QCL, we have demonstrated a successful repetition frequency locking of the laser with a signal to noise ratio of 80 dB. This technique can be employed for the frequency comb and dual-comb operations of terahertz QCLs for high-resolution applications.

scholarly journals pyLLE: A Fast and User Friendly Lugiato-Lefever Equation Solver

2019 ◽  
Vol 124 ◽  
Author(s):  
Gregory Moille ◽  
Qing Li ◽  
Lu Xiyuan ◽  
Kartik Srinivasan
Keyword(s):  
Programming Language ◽  
Frequency Comb ◽  
Mean Field ◽  
Dissipative Structures ◽  
Optical Systems ◽  
User Friendliness ◽  
Frequency Combs ◽  
Nonlinear Resonator ◽  
Comb Generation ◽  
Python Programming

The Lugiato-Lefever Equation (LLE), first developed to provide a description of spatial dissipative structures in optical systems, has recently made a significant impact in the integrated photonics community, where it has been adopted to help understand and predict Kerr-mediated nonlinear optical phenomena such as parametric frequency comb generation inside microresonators. The LLE is essentially an application of the nonlinear Schrodinger equation (NLSE) to a damped, driven Kerr nonlinear resonator, so that a periodic boundary condition is applied. Importantly, a slow-varying time envelope is stipulated, resulting in a mean-field solution in which the field does not vary within a round trip. This constraint, which differentiates the LLE from the more general Ikeda map, significantly simplifies calculations while still providing excellent physical representation for a wide variety of systems. In particular, simulations based on the LLE formalism have enabled modeling that quantitatively agrees with reported experimental results on microcomb generation (e.g., in terms of spectral bandwidth), and have also been central to theoretical studies that have provided better insight into novel nonlinear dynamics that can be supported by Kerr nonlinear microresonators. The great potential of microresonator frequency combs (microcombs) in a wide variety of applications suggests the need for efficient and widely accessible computational tools to more rapidly further their development. Although LLE simulations are commonly performed by research groups working in the field, to our knowledge no free software package for solving this equation in an easy and fast way is currently available. Here, we introduce pyLLE, an open-source LLE solver for microcomb modeling. It combines the user-friendliness of the Python programming language and the computational power of the Julia programming language.

scholarly journals Comb-locked frequency-swept synthesizer for high precision broadband spectroscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Riccardo Gotti ◽  
Thomas Puppe ◽  
Yuriy Mayzlin ◽  
Julian Robinson-Tait ◽  
Szymon Wójtewicz ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Gas Sensing ◽  
Frequency Comb ◽  
Probe Laser ◽  
Line Center ◽  
Frequency Combs ◽  
Promising Tool ◽  
Multiple Species ◽  
Spectral Ranges ◽  
Broadband Spectroscopy

Abstract Frequency combs have made optical metrology accessible to hundreds of laboratories worldwide and they have set new benchmarks in multi-species trace gas sensing for environmental, industrial and medical applications. However, current comb spectrometers privilege either frequency precision and sensitivity through interposition of a cw probe laser with limited tuning range, or spectral coverage and measurement time using the comb itself as an ultra-broadband probe. We overcome this restriction by introducing a comb-locked frequency-swept optical synthesizer that allows a continuous-wave laser to be swept in seconds over spectral ranges of several terahertz while remaining phase locked to an underlying frequency comb. This offers a unique degree of versatility, as the synthesizer can be either repeatedly scanned over a single absorption line to achieve ultimate precision and sensitivity, or swept in seconds over an entire rovibrational band to capture multiple species. The spectrometer enables us to determine line center frequencies with an absolute uncertainty of 30 kHz and at the same time to collect absorption spectra over more than 3 THz with state-of-the-art sensitivity of a few 10−10 cm−1. Beyond precision broadband spectroscopy, the proposed synthesizer is an extremely promising tool to force a breakthrough in terahertz metrology and coherent laser ranging.

scholarly journals Normal-dispersion microresonator Kerr frequency combs

Nanophotonics ◽  
2016 ◽  
Vol 5 (2) ◽  
pp. 244-262 ◽  
Author(s):  
Xiaoxiao Xue ◽  
Minghao Qi ◽  
Andrew M. Weiner
Keyword(s):  
Velocity Dispersion ◽  
Frequency Comb ◽  
Group Velocity Dispersion ◽  
Research Area ◽  
Future Directions ◽  
Normal Dispersion ◽  
Frequency Combs ◽  
The Past ◽  
Dispersion Regime ◽  
Comb Generation

AbstractOptical microresonator-based Kerr frequency comb generation has developed into a hot research area in the past decade. Microresonator combs are promising for portable applications due to their potential for chip-level integration and low power consumption. According to the group velocity dispersion of the microresonator employed, research in this field may be classified into two categories: the anomalous dispersion regime and the normal dispersion regime. In this paper, we discuss the physics of Kerr comb generation in the normal dispersion regime and review recent experimental advances. The potential advantages and future directions of normal dispersion combs are also discussed.

scholarly journals Optical Frequency Comb Generation based on Erbium Fiber Lasers

Nanophotonics ◽  
2016 ◽  
Vol 5 (2) ◽  
pp. 196-213 ◽  
Author(s):  
Stefan Droste ◽  
Gabriel Ycas ◽  
Brian R. Washburn ◽  
Ian Coddington ◽  
Nathan R. Newbury
Keyword(s):  
Frequency Comb ◽  
Building Blocks ◽  
Laser Frequency ◽  
Optical Frequency ◽  
Laser Amplifier ◽  
Optical Frequency Combs ◽  
Frequency Combs ◽  
Comb Generation ◽  
Optical Frequency Metrology ◽  
Frequency Metrology

AbstractOptical frequency combs have revolutionized optical frequency metrology and are being actively investigated in a number of applications outside of pure optical frequency metrology. For reasons of cost, robustness, performance, and flexibility, the erbium fiber laser frequency comb has emerged as the most commonly used frequency comb system and many different designs of erbium fiber frequency combs have been demonstrated. We review the different approaches taken in the design of erbium fiber frequency combs, including the major building blocks of the underlying mode-locked laser, amplifier, supercontinuum generation and actuators for stabilization of the frequency comb.

scholarly journals Kerr optical frequency combs: theory, applications and perspectives

Nanophotonics ◽  
2016 ◽  
Vol 5 (2) ◽  
pp. 214-230 ◽  
Author(s):  
Yanne K. Chembo
Keyword(s):  
Continuous Wave ◽  
Frequency Comb ◽  
Kerr Nonlinearity ◽  
Optical Frequency Comb ◽  
Optical Frequency ◽  
Optical Frequency Combs ◽  
Frequency Combs ◽  
Comprehensive Survey ◽  
Microwave Signal Generation ◽  
Mode Locked Lasers

AbstractThe optical frequency comb technology is one of the most important breakthrough in photonics in recent years. This concept has revolutionized the science of ultra-stable lightwave and microwave signal generation. These combs were originally generated using ultrafast mode-locked lasers, but in the past decade, a simple and elegant alternativewas proposed,which consisted in pumping an ultra-high-Q optical resonator with Kerr nonlinearity using a continuous-wave laser. When optimal conditions are met, the intracavity pump photons are redistributed via four-wave mixing to the neighboring cavity modes, thereby creating the so-called Kerr optical frequency comb. Beyond being energy-efficient, conceptually simple, and structurally robust, Kerr comb generators are very compact devices (millimetric down to micrometric size) which can be integrated on a chip. They are, therefore, considered as very promising candidates to replace femtosecond mode-locked lasers for the generation of broadband and coherent optical frequency combs in the spectral domain, or equivalently, narrow optical pulses in the temporal domain. These combs are, moreover, expected to provide breakthroughs in many technological areas, such as integrated photonics, metrology, optical telecommunications, and aerospace engineering. The purpose of this review article is to present a comprehensive survey of the topic of Kerr optical frequency combs.We provide an overview of the main theoretical and experimental results that have been obtained so far. We also highlight the potential of Kerr combs for current or prospective applications, and discuss as well some of the open challenges that are to be met at the fundamental and applied level.

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