Papers - Ota, Yasutomo

High-Q two-dimensional photonic crystal nanocavity on glass with an upper glass thin film

R Kawata, A Fujita, N Pholsen, S Iwamoto, Y Ota

arXiv preprint arXiv:2311.00935  2023

Joint Work

Faraday rotator based on a silicon photonic crystal slab on a bismuth-substituted yttrium iron garnet thin film

S Gao, Y Ota, T Liu, F Tian, S Iwamoto

Applied Physics Express 16 (7), 072003 (Applied Physics Express)  16 ( 7 )  2023

Joint Work,  ISSN  18820778

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We report the design of an ultrathin Faraday rotator consisting of a silicon photonic crystal (PhC) slab on a bismuth-substituted yttrium iron garnet (Bi:YIG) thin film. By directing light into guided modes in the Bi:YIG layer via diffraction in the PhC layer, we numerically demonstrate a Faraday rotation angle of ∼45° at a telecom wavelength with a Bi:YIG layer thickness of only ∼500 nm. This structure permits a high light transmittance of about 70%, enabled by electromagnetically induced transparency. The proposed design only requires nanopatterning of the Si layer, providing a viable route to practical ultrathin Faraday rotators.

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Topologically-Protected Single-Photon Sources with Topological Slow Light Photonic Crystal Waveguides

Kuruma K., Yoshimi H., Ota Y., Katsumi R., Kakuda M., Arakawa Y., Iwamoto S.

Laser and Photonics Reviews (Laser and Photonics Reviews)  16 ( 8 )  2022.08

Joint Work,  ISSN  18638880

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Slow light waveguides are advantageous for implementing high-performance single-photon sources required for scalable operation of integrated quantum photonic circuits (IQPCs), though such waveguides are known to suffer from propagation loss due to backscattering. A way to overcome the drawback is to use topological photonics, in which robust waveguiding in topologically-protected optical modes has recently been demonstrated. Here, single-photon sources are reported using single quantum dots (QDs) embedded in topological slow light waveguides based on valley photonic crystals. Purcell-enhanced single-photon emission is demonstrated from a QD into a topological slow light mode with a group index over 20 and its robust propagation even under the presence of sharp bends. These results pave the way for the realization of robust and high-performance single-photon sources indispensable for IQPCs.

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Topological Band Gaps Enlarged in Epsilon-Near-Zero Magneto-Optical Photonic Crystals

T Liu, N Kobayashi, K Ikeda, Y Ota, S Iwamoto

ACS Photonics (American Chemical Society (ACS))  9 ( 5 ) 1621 - 1626 2022

Joint Work,  ISSN  2330-4022

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Topological photonics provides exciting and emerging opportunities for the manipulation of light. As the photonic analogue of quantum Hall edge states, chiral edge modes, arising at the interface between two photonic topological structures with different Chern numbers, hold great promise for robust transport of light against disorders and defects. However, for magneto-optical material-based topological photonic crystals, the transport performance of chiral edge modes is strongly dependent on the topological gap sizes, which are usually very narrow at optical frequencies due to the lack of magneto-optical materials with strong nonreciprocal responses. Here, we numerically demonstrated that the introduction of an epsilon-near-zero effect to magneto-optical photonic crystals could remarkably enlarge topological gap sizes due to the boosted magneto-optical response. Eigenmode calculation results show that the boosted magneto-optical response correlates to the enhanced nonreciprocal power flows in magnetized photonic crystals with an epsilon-near-zero diagonal permittivity. The enlarged topological band gap leads to the broadband and well-confined chiral edge modes propagating along the magnetized boundary between two oppositely magnetized photonic crystals. More importantly, such mode propagation shows strong robustness against sharp bends and large defects. In principle, our proposal for the enlargement of topological photonic band gaps could also be valid in photonic crystal slabs or even three-dimensional photonic crystals. Our results not only suggest the possibility to improve the transport performance of one-way modes in magneto-optical photonic crystals but also enrich the physical understanding of the epsilon-near-zero effect-based topological photonics.

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CMOS-compatible integration of telecom band InAs/InP quantum-dot single-photon sources on a Si chip using transfer printing

R Katsumi, Y Ota, T Tajiri, S Iwamoto, K Ranbir, JP Reithmaier, ...

Applied Physics Express 16 (1), 012004 (IOP Publishing)  16 ( 1 ) 012004 - 012004 2022

Joint Work,  ISSN  1882-0778

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Abstract

We report the hybrid integration of a telecom band InAs/InP quantum-dot (QD) single-photon source on a CMOS-processed Si photonics chip using transfer printing. The integration technique allows for the assembly of photonic components in a pick-and-place operation and therefore can introduce them on Si photonics chips after completing the entire CMOS-compatible fabrication processes. We demonstrate telecom single-photon generation from an InAs/InP QD integrated on Si and its coupling into a waveguide. We also demonstrate the integration of a QD on a fiber-pigtailed Si chip and single-photon output through the optical fiber, showing a novel pathway for modularizing solid-state quantum light sources.

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Topologically‐protected single‐photon sources with topological slow light photonic crystal waveguides

K Kuruma, H Yoshimi, Y Ota, R Katsumi, M Kakuda, Y Arakawa, ...

Laser & Photonics Reviews 16 (8), 2200077 (Wiley)  16 ( 8 ) 2200077 - 2200077 2022

Joint Work,  ISSN  1863-8880

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Topological modes observed in Si photonics SSH integrated circuit

R Nakamura, T Nakama, A Balčytis, T Ozawa, Y Ota, S Iwamoto, H Ito, ...

Conference on Lasers and Electro-Optics/Pacific Rim, CThA8D_02 (Optics InfoBase Conference Papers)   2022

Joint Work

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We fabricated a sophisticated Si photonic integrated circuit for investigating topological photonics SSH model. In the selective excitation and observation of SSH coupled microrings, we observed the wavefunctions of edge and bulk modes.

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Semiconductor topological nanophotonics incorporating light emitters

Y Ota, Y Arakawa, S Iwamoto

International Conference on Metamaterials, Photonic Crystals and Plasmonics … (International Conference on Metamaterials, Photonic Crystals and Plasmonics)     412 - 413 2022

Joint Work

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Topological photonic crystals made of compound semiconductors are a fascinating platform to develop topological nanophotonic devices with active functionalities. In this contribution, will discuss recent progress in IIIV-semiconductor topological nanophotonics incorporating optical gain media and quantum emitters. We will review several ways to realize topological nanocavities and topological slow light waveguides, both of which can significantly enhance light-matter interactions with embedded light emitters. These photonic structures enable the realization of topological nano/microlasers and quantum light sources capable of robust operation.

Micro-transfer-printed membrane DR lasers on Si waveguide modulated with 50-Gbit/s NRZ signal

Y Maeda, T Fujii, T Aihara, T Hiraki, K Takeda, T Tsuchizawa, H Sugiyama, ...

European Conference and Exhibition on Optical Communication, We1E. 4 (2022 European Conference on Optical Communication, ECOC 2022)   2022

Joint Work

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We fabricate directly modulated membrane distributed reflector lasers on a Si waveguide by using the micro-transfer printing. A low threshold current of 1.2 mA and good optical coupling between the laser output and 220-nm-thick Si waveguides are achieved. 50-Gbit/s NRZ signal modulation is also demonstrated.

Intrinsically chiral modes near exceptional points in modified H1 photonic crystal cavity modes

CF Fong, Y Ota, Y Arakawa, S Iwamoto, YK Kato

2022 Conference on Lasers and Electro-Optics (CLEO), 1-2  2022

Joint Work

Intrinsically chiral modes near exceptional points in modified H1 photonic crystal cavity modes

Fong C.F., Ota Y., Arakawa Y., Iwamoto S., Kato Y.K.

Optics InfoBase Conference Papers (Optics InfoBase Conference Papers)   2022

Joint Work

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We propose a scheme to generate intrinsically chiral modes via non-Hermitian backscattering caused by the loss-induced imaginary coupling between the two orthogonal linearly polarized dipole modes in the H1 photonic crystal cavity.

Intrinsically chiral modes near exceptional points in modified H1 photonic crystal cavity modes

Fong C.F., Ota Y., Arakawa Y., Iwamoto S., Kato Y.K.

2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings (2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings)   2022

Joint Work

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We propose a scheme to generate intrinsically chiral modes via non-Hermitian backscattering caused by the loss-induced imaginary coupling between the two orthogonal linearly polarized dipole modes in the H1 photonic crystal cavity.

Hybrid Integration of Quantum-Dot Non-classical Light Sources on Si

R Katsumi, Y Ota, S Iwamoto, Y Arakawa

Progress in Nanophotonics 7, 93-121 (Topics in Applied Physics)  147   93 - 121 2022

Joint Work,  ISSN  03034216

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This chapter describes the hybrid integration of quantum-dot single-photon sources (QD SPSs) on Si toward the scalable Si quantum photonics. In this study, transfer printing (TP) has been extensively investigated, a technique that simply relies on pick-and-place integration based on van der Waals force, and thus is fully compatible with the CMOS back-end process to exploit mature CMOS technology. Using TP, QD SPSs were hybrid integrated on a CMOS Si chip. It was confirmed that the integrated QDs can generate single photons on a CMOS Si chip. We also observed efficient waveguide coupling of emitted single photons. Furthermore, we extended our TP method for investigating the multiple identical SPSs hybrid integrated on Si. We believe that our TP-based approach will provide a novel pathway toward the scalable implementation of multiple identical QD SPSs on the same CMOS Si chip.

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High-temperature operation of membrane DR lasers integrated with Si waveguide by micro-transfer printing method

Y Maeda, T Aihara, T Fujii, T Hiraki, K Takeda, T Tsuchizawa, H Sugiyama, ...

2022 28th International Semiconductor Laser Conference (ISLC), 1-2 (Conference Digest - IEEE International Semiconductor Laser Conference)  2022-October 2022

Joint Work,  ISSN  08999406

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We fabricate a membrane distributed-reflector lasers with a Si waveguide by using micro-transfer printing, achieving a low threshold current of 1.1-3.7 mA in a temperature range of 25-80 C and good optical coupling between the laser output and 220-nm-thick Si waveguides.

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Generation of Optical Skyrmion Crystal Beams using Polarization-Controlled Coupled-Cavity Systems

W LIN, S IWAMOTO, Y OTA

村田学術振興財団年報, 495-502  2022

Joint Work

Exceptional-point encirclement in an integrated non-Hermitian optomechanical system

Tian F., Ota Y., Iwamoto S.

Optics InfoBase Conference Papers (Optics InfoBase Conference Papers)   2022

Joint Work

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We propose and numerically demonstrate an integrated non-Hermitian optomechanical system capable of exceptional-point encirclement in a deterministic manner. The proposed scheme opens a way for investigating non-Hermitian optomechanics on chip.

Exceptional-point encirclement in an integrated non-Hermitian optomechanical system

Tian F., Ota Y., Iwamoto S.

2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings (2022 Conference on Lasers and Electro-Optics, CLEO 2022 - Proceedings)   2022

Joint Work

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We propose and numerically demonstrate an integrated nonHermitian optomechanical system capable of exceptionalpoint encirclement in a deterministic manner. The proposed scheme opens a way for investigating nonHermitian optomechanics on chip.

Exceptional-point encirclement in an integrated non-Hermitian optomechanical system

F Tian, Y Ota, S Iwamoto

CLEO: Applications and Technology, JTh3A. 64  2022

Joint Work

Design of an All-dielectric Magneto-optical Metasurface with Giant Faraday Effect and High Light Transmission

S Gao, Y Ota, T Liu, S Iwamoto

Conference on Lasers and Electro-Optics/Pacific Rim, CFA8G_02 (Optics InfoBase Conference Papers)   2022

Joint Work

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We design an all-dielectric metasurface exhibiting giant enhancement of magneto-optical Faraday rotation and high light transmission. A 760-times larger Faraday rotation than that in the unprocessed host material of the same thickness was numerically observed.

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Design of a Quantum-Dot Single-Photon Source on a Silicon Nitride Waveguide for Efficient Photon Generation by Resonant Excitation

N Pholsen, Y Ota, S Iwamoto

2022 28th International Semiconductor Laser Conference (ISLC), 1-2 (Conference Digest - IEEE International Semiconductor Laser Conference)  2022-October 2022

Joint Work,  ISSN  08999406

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We design a quantum-dot single-photon source with a defect-based photonic crystal cavity on a SiN waveguide that subdues crosstalk from resonant excitation and has >90% coupling efficiency. It is expected to efficiently generate single photons with high purity and indistinguishability for scalable integrated quantum photonics.

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