High-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Q</mml:mi></mml:math>resonant modes in a photonic crystal heterostructure nanocavity and applicability to a Raman silicon laser

Takahashi, Yasushi; Inui, Yoshitaka; Chihara, Masahiro; Asano, Tanemasa; Terawaki, Ryo; Noda, Susumu

doi:10.1103/physrevb.88.235313

Cited by 26 publications

(12 citation statements)

References 39 publications

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“…Since Raman Si lasers enable continuous-wave (cw) operation at room temperature in the telecommunication wavelength regime [13][14][15], they are attractive for information technologies. We have developed a Raman Si laser based on a highquality-(high-Q)-factor photonic-crystal (PC) nanocavity with a resonator size of 10 µm that enables an ultralow threshold of approximately 1 µW [16,17]. Such a small, low-threshold device is suited for dense integration on Si photonic circuits, which can be employed for applications such as cw laser sources and all-optical switching devices.…”

Section: Introductionmentioning

confidence: 99%

Lasing Dynamics of Optically-Pumped Ultralow-Threshold Raman Silicon Nanocavity Lasers

et al. 2018

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We investigate the lasing dynamics of optically-pumped submicrowatt-threshold Raman silicon lasers that employ a high-quality (high-Q) nanocavity design. The measurements reveal that free carriers generated by two-photon absorption induce dynamic effects during the initial lasing process, even at the very low threshold power of 0.12 µW. At higher excitation powers, the Raman laser signal exhibits a significant reduction within a few hundred nanoseconds after the initial rise, followed by clear oscillations. We find that the temporal behavior of the laser signal strongly depends on the excitation wavelength. However, the Raman laser signal converges to a stable continuous operation within a few microseconds after the initial rise for any excitation power employed in this work. Numerical simulations indicate that the oscillations reflect the dynamic shift of the resonant wavelength due to the thermo-optic effect and the carrier-plasma effect, which are induced by free carriers generated via two-photon absorption. These results are useful for understanding the correct design of future devices that employ Raman silicon nanocavity lasers.

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Section: Introductionmentioning

confidence: 99%

Lasing Dynamics of Optically-Pumped Ultralow-Threshold Raman Silicon Nanocavity Lasers

et al. 2018

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“…The nanocavities consist of a line defect of 27 missing air holes. They are fabricated along the [100] direction of the (100) SOI substrate in order to enhance the Raman gain . By comparing the present SEM images with those from the high‐ Q cavities in the previous Section 4.1, it can be confirmed that the different direction of the nanocavity used in the Raman laser does not influence the fabrication accuracy.…”

Section: Resultsmentioning

confidence: 58%

“…The increase of a leads to a decrease in the band frequencies of the two propagation modes for the line defect as shown in Figure b. As a result of mode gap confinement, two nanocavity modes are formed . The low‐ and high‐frequency modes are referred to as the 1st and 2nd nanocavity mode, respectively.…”

Section: Nanocavity Structurementioning

confidence: 98%

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Ultrahigh‐Q Photonic Nanocavity Devices on a Dual Thickness SOI Substrate Operating at Both 1.31‐ and 1.55‐µm Telecommunication Wavelength Bands

Kuwabara

Noda

Takahashi

2019

Laser & Photonics Reviews

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A feasible method for integrating several silicon (Si) photonic devices with operating wavelengths separated by several hundred nanometers on a single chip will greatly help increasing capacities of small optical communication modules. This work demonstrates the integration of two photonic crystal nanocavity devices that exhibit ultrahigh quality factors (Q) and operate at the 1.31‐ and 1.55‐µm bands. A dual thickness Si‐on‐insulator substrate forms the base of the device. The two nanocavity patterns are defined by electron beam lithography on the thick and thin substrate regions and are transferred to the top Si layer by performing plasma etching only once. All dimensions of the fabricated 1.31‐µm nanocavity are ≈15.5% smaller (1–1.31/1.55) than those of the 1.55‐µm nanocavity; that is, they can be treated with the same photonic band diagram. Both nanocavities exhibit an ultrahigh Q > 2.0 × 106 and enable fabrication of nanocavity‐based Raman lasers for the 1.31/1.55‐µm bands with sub‐microwatt threshold.

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“…One-dimensional photonic crystal (1DPC) is a well-known concept with broad fields of application since their discovery in 1987 [1,2]. Their initial development was motivated to improve laser and optical fiber technologies [3][4][5], but today they have been extended to other commercial devices, like optical filters [6,7], high Q-photonic cavities [8,9], photocatalysis [10,11], high-temperature sensitive sensors [12], magnetoplasmonics [13], metamaterials [14], light tailoring [15], or even energy functionalization. [16].…”

Section: Introductionmentioning

confidence: 99%

Angular Dependence of Photonic Crystal Coupled to Photovoltaic Solar Cell

Delgado-Sánchez

Lillo-Bravo

2020

Applied Sciences

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Photonic crystals have the advantage of minimizing thermal losses from solar cells, reflecting the solar radiation that is not absorbed by the photovoltaic device. To optimize this optical response, photonic crystals are designed considering the relative position of the Bragg peak and the bandgap of the solar cell, under normal incident irradiation conditions. The aim of this research article was to determine experimentally the optical limits of a solar cell coupled to a photonic crystal acting as beam splitter. For that purpose, the photovoltaic system was characterized under indoor and outdoor conditions; angular dependence of the irradiation source was determined in each case, and both results were compared with good agreement. Moreover, other parameters such as irradiation spectrum and polarization of the light were investigated. The main conclusion is that photovoltaic performance is highly affected by the Bragg peak shifting and the profile is distorted, due to the angular dependence with the sun. These experimental limits must be considered at the early design stage to avoid performance losses.

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High-Qresonant modes in a photonic crystal heterostructure nanocavity and applicability to a Raman silicon laser

Cited by 26 publications

References 39 publications

Lasing Dynamics of Optically-Pumped Ultralow-Threshold Raman Silicon Nanocavity Lasers

Lasing Dynamics of Optically-Pumped Ultralow-Threshold Raman Silicon Nanocavity Lasers

Ultrahigh‐Q Photonic Nanocavity Devices on a Dual Thickness SOI Substrate Operating at Both 1.31‐ and 1.55‐µm Telecommunication Wavelength Bands

Angular Dependence of Photonic Crystal Coupled to Photovoltaic Solar Cell

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