Microresonator Kerr frequency combs with high conversion efficiency

Abstract

Microresonator-based Kerr frequency comb (microcomb) generation can potentially revolutionize a variety of applications ranging from telecommunications to optical frequency synthesis. However, phase-locked microcombs have generally had low conversion efficiency limited to a few percent. Here we report experimental results that achieve ~30% conversion efficiency (~200 mW on-chip comb power excluding the pump) in the fiber telecommunication band with broadband mode-locked dark-pulse combs. We present a general analysis on the efficiency which is applicable to any phase-locked microcomb state. The effective coupling condition for the pump as well as the duty cycle of localized time-domain structures play a key role in determining the conversion efficiency. Our observation of high efficiency comb states is relevant for applications such as optical communications which require high power per comb line.Comment: 4 pages, 4 figures, typos correcte

Arbitrary Energy‐Preserving Control of Optical Pulse Trains and Frequency Combs through Generalized Talbot Effects

“…If the transformation is entirely completed, in the frequency domain, this translates into a division of the corresponding frequency comb FSR by the factor r, that is, from r = t −1 r to r −1 r . Different combinations of temporal and spectral Talbot phases could be designed to achieve the same multiplication factor; that is, different values of the parameters p, q, s, and m in Equations (4) and (6). We describe the general solution of the problem and then provide guidelines to achieve particular solutions that minimize the displacement on the temporal Talbot carpet (corresponding to the case of minimum required dispersion in a practical implementation).…”

“…Since the first demonstrations of optical phase‐locking and the first mode‐locked laser developments, the capability to generate precisely timed periodic trains of optical pulses has pushed forward many fields of science and technology. Extensive effort has been further devoted to the generation and control of optical frequency combs, the frequency‐domain counterpart of time‐periodic coherent optical pulse trains. A frequency comb consists of a set of equally‐spaced spectral components (comb lines), with a frequency spacing referred to as the free spectral range (FSR).…”

“…The reported numerical studies fully validate the presented theoretical framework and shed light on crucial aspects of the proposed methods, consistently with previously reported experimental results. Important considerations concerning the practical, real-world implementation of the described schemes, according to the needed specifications for different applications, are also discussed.of optical frequency combs, [2][3][4][5][6][7][8][9][10][11][12][13][14] the frequency-domain counterpart of timeperiodic coherent optical pulse trains. A frequency comb consists of a set of equally-spaced spectral components (comb lines), with a frequency spacing referred to as the free spectral range (FSR).…”

“…of optical frequency combs, [2][3][4][5][6][7][8][9][10][11][12][13][14] the frequency-domain counterpart of timeperiodic coherent optical pulse trains. A frequency comb consists of a set of equally-spaced spectral components (comb lines), with a frequency spacing referred to as the free spectral range (FSR).…”

Switching Dynamics of Dark Solitons in Kerr Microresonators

“…These localized waveforms also exhibit breathing dynamics 31 and have intriguing connections to sneaker waves found in hydrodynamics, called flaticons 32 and platicons 33 in optics. In comparison to DKS, the physics of dark-pulse Kerr combs is less understood due in part to a complex interplay between multiple modes and thermal dynamics in the cavity, but these microcombs are more efficient in converting the pump power into useful comb light 34 -an aspect that is particularly promising for coherent optical communications 35,36 . Some key questions remain unanswered, such as what the pathway to their generation is, starting from a continuous-wave (CW) waveform, and whether this transition is accompanied by similar switching dynamics to what has been observed in DKS.…”