High-<i>Q</i> THz Photonic Crystal Cavity on a Low-Loss Suspended Silicon Platform

Akiki, Elias; Verstuyft, Mattias; Kuyken, Bart; Walter, Benjamin; Faucher, M.; Lampin, Jean‐François; Ducournau, Guillaume; Vanwolleghem, Mathias

doi:10.1109/tthz.2020.3019928

Cited by 20 publications

(13 citation statements)

References 37 publications

(44 reference statements)

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“…[ 35 ] Despite the sharp corners in the loop, the kink states circulate with minimal counter‐propagation, resisting the formation of standing waves, hence giving rise to a series of regularly spaced resonances (see Section S2 in the Supporting Information). The topological cavity is fundamentally different from traditional cavity designs such as photonic crystal cavities [ 36–38 ] or nanobeam cavities, [ 39 ] which rely on careful structural optimization. The geometrical insensitivity of the topological cavity offers excellent flexibility in design and fabrication; although we have focused on a parallelogram‐shaped loop with four sharp corners, it is possible to design cavities with other shapes (see Section S2 in the Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

“…The reported Q factor is the highest so far at THz frequencies. PC cavity [36,38,53] Racetrack ring [54] 2839 ≈77 0.218 No Yes ≈13λ 0 WGM sphere [55] 15 000 ≈41 0.62 No Yes ≈26λ 0 WGM bubble [56] 440 ≈1000 0.47 No No ≈31λ 0 WGM resonator [57,58] 1867 www.advmat.de www.advancedsciencenews.com critical coupling by photoexcitation to control the intensity of the resonant transmission dips.…”

Section: Tablementioning

confidence: 99%

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Active Ultrahigh‐Q (0.2 × 10⁶) THz Topological Cavities on a Chip

et al. 2022

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ever-increasing demand for higher data transfer rates in wired and wireless communication links. The exponential growth in data rates has pushed the carrier frequencies toward the higher spectral region, the terahertz (THz) band. The availability of ultrahigh bandwidths in the THz region (0.1-10 THz) allows achievement of terabits per second connectivity, [1] making it ideal for sixth-generation (6G) communication. However, with the emergence of 6G networks, the development of efficient on-chip communication with low loss and active control is crucial to handle and process the massive volume of data transmitted using THz carrier frequencies. The existing solutions for high-speed on-chip interconnects, including copper-based electrical interconnects (EIs), [2] suffer from limited bandwidth, and optical interconnects (OIs) [3] possess integration complexity and electronic-to-optical (EO/OE) conversion losses. To circumvent the existing performance gaps (in terms of bandwidths, energy efficiency, and system simplicity) of on-chip interconnects, THz interconnects [4,5] offer a potential route by leveraging the advantages of both the electronic and photonic worlds. However, scaling carrier frequencies up to sub-THz and beyond requires further innovation toward on-chip photonic solutions to support higher radio-frequency (RF) electronics Rapid scaling of semiconductor devices has led to an increase in the number of processor cores and integrated functionalities onto a single chip to support the growing demands of high-speed and large-volume consumer electronics. To meet this burgeoning demand, an improved interconnect capacity in terms of bandwidth density and active tunability is required for enhanced throughput and energy efficiency. Low-loss terahertz silicon interconnects with larger bandwidth offer a solution for the existing inter-/intrachip bandwidth density and energy-efficiency bottleneck. Here, a low-loss terahertz topological interconnect-cavity system is presented that can actively route signals through sharp bends, by critically coupling to a topological cavity with an ultrahigh-quality (Q) factor of 0.2 × 10 6 . The topologically protected large Q factor cavity enables energy-efficient optical control showing 60 dB modulation. Dynamic control is further demonstrated of the critical coupling between the topological interconnect-cavity for on-chip active tailoring of the cavity resonance linewidth, frequency, and modulation through complete suppression of the back reflection. The silicon topological cavity is complementary metal-oxide-semiconductor (CMOS)-compatible and highly desirable for hybrid electronic-photonic technologies for sixth (6G) generation terahertz communication devices. Ultrahigh-Q cavity also paves the path for designing ultrasensitive topological sensors, terahertz topological integrated circuits, and nonlinear topological photonic devices.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202202370.

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Section: Resultsmentioning

confidence: 99%

Section: Tablementioning

confidence: 99%

Active Ultrahigh‐Q (0.2 × 10⁶) THz Topological Cavities on a Chip

et al. 2022

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“…This allows us to effectively control the interference in transmitted and reflected waves, thus generating the desired stopband or passband response over a particular frequency band. 6,7 Accordingly, a number of terahertz filters based on microwave [8][9][10] and optical [11][12][13] waveguiding structures have been proposed. However, microwavetechnology-based filters suffer from high metallic loss at terahertz bands.…”

Section: Introductionmentioning

confidence: 99%

“…From the optics side, thin-film filters consisting of multi-layer dielectrics 11 are also not integratable despite their structural and design simplicity. Furthermore, although one dimensional photonic crystal cavities 13 have good integrability, the passband has significant fluctuations resulting from the strong refractive index contrast between air and silicon. In addition, the 3-dB bandwidth tends to be large due to the same reason, thus limiting designability.…”

Section: Introductionmentioning

confidence: 99%

Effective-medium-clad Bragg grating filters

2021

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We propose a series of integrated Bragg grating filters with performance enhancement via the concept of effective medium. The bandstop filters are built in a high-resistivity silicon wafer and operated over the with in-plane polarization. The proposed designs use an additional degree of freedom in controlling the effective refractive index so as to fully use the potential of the Bragg grating structures. As a result, the high insertion loss typically observed at the low-frequency bound of the filters due to weak wave confinement can be reduced, while radiation caused by the leaky-wave effect at the high-frequency bound is minimized, allowing for a 40% operation fractional bandwidth. These features are not achievable with conventional waveguide Bragg grating filters. All-silicon prototypes of filter samples are experimentally validated, demonstrating promising performance for a wide range of terahertz applications. The techniques to improve the filter characteristics by controlling the effective medium can be adopted in both microwave and optics domains.

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“…In [3] we proposed the design of an integrated THz PA gas sensor for monitoring food spoilage. It is based on the confinement of the THz light in a PhC cavity with high Q factors [4] to increase the light-molecules interaction. Gas molecules absorbing the THz modulated light produce sound waves that are enhanced inside an acoustical cylinder which is at the same time the etched hole of the PhC THz cavity and then detected by a Poly-Si microphone covering the bottom of the cylinder.…”

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confidence: 99%