Ultra-smooth silicon nitride waveguides based on the Damascene reflow process: fabrication and loss origins

Pfeiffer, Martin H. P.; Liu, Junqiu; Raja, Arslan S.; Morais, Tiago; Ghadiani, Bahareh; Kippenberg, Tobias J.

doi:10.1364/optica.5.000884

Cited by 204 publications

(136 citation statements)

References 53 publications

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“…For microresonators with no intrinsic losses, conversion efficiency close to 100% is expected. By considering practical microresonators with an intrinsic Q of 10 7 (demonstrated with state-of-the-art silicon nitride integration technique [31], [32], [44]), conversion efficiency around 80% is achievable (see Supplementary Section 7 for more discussions). The super-efficient soliton comb will benefit a wide range of applications including biological and chemical sensing [10], high-capacity and long-haul fiber telecommunications [11], fast ranging lidar [13], [14], microwave photonic signal processing [16], [17], etc.…”

Section: Summary and Discussionmentioning

confidence: 99%

Super-efficient temporal solitons in mutually coupled optical cavities

2019

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A coherently driven Kerr optical cavity is able to convert a continuous-wave laser to a sequence of ultrashort soliton pulses, enabling the generation of broadband and mode-locked frequency combs. Kerr cavity solitons are balanced through an energy exchange with the driving pump field. Improving the energy conversion efficiency from the pump to the soliton is of great significance for practical applications, but remains an outstanding challenge due to a limited temporal overlap between the soliton and the pump. Here, we report the discovery of temporal Kerr solitons in mutually coupled cavities instead of a traditional single cavity. We propose a strategy for breaking the limitation of pump-to-soliton energy conversion, and connect the underlying mechanism to impedance matching in radiofrequency electronic circuits. With macro optical fiber ring cavities which share the same physical model as miniature optical microresonators, we demonstrate nearly one-order improvement of the efficiency. Our findings pave the way towards super-efficient soliton microcombs based on optical microresonators with ultra-high quality factors. Dissipative solitons are localized particle-like structures which are double balanced by gain and loss, and nonlinearity and dispersion (or diffraction) [1], [2]. The study of dissipative solitons spreads in a large variety of different areas, has led to many exciting scientific findings and useful applications. Dissipative temporal solitons in coherently driven Kerr optical cavities have attracted great interest in recent years. The study arose in two different scenarios. One focused in the time domain, i.e., exciting and maintaining solitons to form optical buffers [3]; the other focused in the frequency domain, i.e., optical frequency comb generation with miniature microresonators [4]. The experimental demonstration of temporal cavity solitons was first performed in macro fiber ring cavities [3], and then repeated in optical microresonators [5], [6]. The researches from frequency and time domains then merged to a clear subject of cavity solitons [7], [8]. The discovery of microresonator solitons truly brings cavity solitons to a hot active research area because it enables integrated coherent frequency comb sources which may revolutionize many applications [9]- [17].Following the historical trend, the researches of cavity solitons nowadays have been performed on mainly two platforms. One is macro fiber ring cavities [3], [18]- [21]; the other is miniature optical microcavities [5], [8], [22]-[26]. In comparison, fiber cavities are more convenient for precise frequency detuning control and can be easily investigated in real time due to their much slower time scale; microresonators are particularly useful as compact frequency comb generators for practical applications. Previous studies have shown that both platforms share the similar physical model and useful technical hints may be learned from each other.

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Section: Summary and Discussionmentioning

confidence: 99%

Super-efficient temporal solitons in mutually coupled optical cavities

2019

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“…The recent progress on high-Q MRR in Si 3 N 4 [31] could also provide an avenue for more complex quantum communication tasks such as multiphoton entanglement swapping experiments, or coupling to quantum memories. An area where significant impact could be made is in better mode matching between the fibre and bus waveguide for fibre pigtailing, which would be important to increase both the coupling and heralding efficiencies.…”

Section: Discussionmentioning

confidence: 99%

High-rate photon pairs and sequential Time-Bin entanglement with Si₃N₄ microring resonators

Samara¹,

Martin²,

Autebert³

et al. 2019

Opt. Express

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Integrated photonics is increasing in importance for compact, robust, and scalable enabling quantum technologies. This is particularly interesting for developing quantum communication networks, where resources need to be deployed in the field. We exploit photonic chip-based Si 3 N 4 ring microresonators to realise a photon pair source with low-loss, high-noise suppression and coincidence rates of 80×10 3 s −1 . A simple photonic noise characterisation technique is presented that distinguishes linear and nonlinear contributions useful for system design and optimisation. We then demonstrate an all-fibre 750 MHz clock-rate sequential Time-Bin entanglement scheme with raw interference visibilities > 98 %.

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“…Then a layer of Si3N4 is deposited on the whole wafer, as well as in the trenches. In this process, the predefined trenches not only prevent the crack from propagating, but also function as the mold of the waveguides [355] [356]. To further reduce the scattering loss and increase quality factor, several different strategies have been employed including optimizing the reactive ion etching (RIE) recipe, performing a reflow step to improve sidewall roughness, and using chemical mechanical polishing (CMP) to reduce top surface roughness.…”

Section: Silicon Nitridementioning

confidence: 99%

Emerging material systems for integrated optical Kerr frequency combs

et al. 2020

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The experimental realization of a Kerr frequency comb represented the convergence of research in materials, physics, and engineering, and this symbiotic relationship continues to underpin efforts in comb innovation today. While the initial focus developing cavity-based frequency combs relied on existing microresonator architectures and classic optical materials, in recent years, this trend has been disrupted. This paper reviews the latest achievements in frequency comb generation using resonant cavities, placing them within the broader historical context of the field. After presenting well-established material systems and device designs, the emerging materials and device architectures are examined. Specifically, the unconventional material systems as well as atypical device designs that have enabled tailored dispersion profiles and improved comb performance are compared to the current state of art. The remaining challenges and future outlook for the field of cavity-based frequency combs is evaluated.

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Ultra-smooth silicon nitride waveguides based on the Damascene reflow process: fabrication and loss origins

Cited by 204 publications

References 53 publications

Super-efficient temporal solitons in mutually coupled optical cavities

Super-efficient temporal solitons in mutually coupled optical cavities

High-rate photon pairs and sequential Time-Bin entanglement with Si₃N₄ microring resonators

Emerging material systems for integrated optical Kerr frequency combs

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Ultra-smooth silicon nitride waveguides based on the Damascene reflow process: fabrication and loss origins

Cited by 204 publications

References 53 publications

Super-efficient temporal solitons in mutually coupled optical cavities

Super-efficient temporal solitons in mutually coupled optical cavities

High-rate photon pairs and sequential Time-Bin entanglement with Si3N4 microring resonators

Emerging material systems for integrated optical Kerr frequency combs

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Product

Resources

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High-rate photon pairs and sequential Time-Bin entanglement with Si₃N₄ microring resonators