CLEOPR 2022 Riku Imamura


CLEOPR 2022 Participation Report

31st July - 5th August 2022, Sapporo Convention Center

Riku Imamura, 2nd year Ph.

1. presentation by the presenter

Title Mode-locked Operation in a Coupled Microresonator System with Gain
and Nonlinear Loss
Authors Riku Imamura1 , Yuki Tate1 , Ayata Nakashima1 , Keigo Nagashima1 , Shun Fujii1,2 , Takasumi Tanabe1
Affiliations 1. Keio Univ. (Japan), 2.
Lecture No. CThA8C-03

A presentation was made on the development of a pulsed light source with erbium ions. In our laboratory, we have analyzed the mode-locking condition of a single resonator with erbium ions (gain) and a saturable absorber (non-linear loss). In this presentation, it is clarified that the gain required for mode-locking is reduced by using a gain medium and a linear loss medium as a coupled resonator system instead of a single resonator system. In addition, based on actual experimental observations, a numerical analysis was conducted to determine how much the difference in diameter between the two resonators can be tolerated.
Two questions were asked during the Q&A session. The first was a question about the linear loss of carbon nanotubes used as saturable absorbers, and the second was a question about the threshold in mode synchronization. Although the session started at 9:00 a.m., there were about 20 people in the audience, and I was nervous until just before my presentation because it was my first on-site presentation in a long time.

2. presentations attended

Title: Erbium-doped Rare-Earth Oxide Thin Film Waveguides for Integrated
Quantum Photonic Devices
Authors: Xuejun Xu1, Masaya Hiraishi1,2, Tomohiro Inaba1, Tai Tsuchizawa3
Atsushi Ishizawa1 , Haruki Sanada1 , Takehiko Tawara4
Jevon Longdell2 , Katsuya Oguri1 , Hideki Gotoh1
Affiliations: 1. NTT Basic Research Laboratories (Japan), 2. University (Japan)
Lecture Number: CTuP8A-01

NTT research group presented a rare-earth doped waveguide, in which a rare-earth doped oxide is formed between a Si substrate and an SiN waveguide. The rare-earth ions are Er ions, and the host material is Gd2O3The reason is that Gd The reason is that Gd2O3This is because the mismatch between the electrons and Er ions is smaller than that of other materials, which enables the formation of a waveguide on an Si substrate while maintaining high crystal quality. The PL linewidth in the 1550 nm band of the device is as narrow as 82 GHz.
What was impressive in the presentation was that the experiments were carried out at a low temperature of 2.3 K. The reason for this was that rare earth luminescence has low coherence at room temperature. The combination of rare earth additives and SiN has attracted a lot of attention from domestic research groups, which is a notable current event.

Title: Non-Hermitian nanophotonics with photonic crystal cavities
Authors: Kenta Takata1,2, Kengo Nozaki1,2, Eiichi Kuramochi1,2, Shinji Matsuo1,3,
Koji Takeda1,3, Takuro Fujii1,3, Shota Kita1,2, Nathan Roberts2, Akihiko Shinya1,2, Masaya Notomi1,2,4
Affiliations: 1. NTT Nanophotonics Center (Japan), 2. NTT Basic Research Labs.(Japan), 3. NTT Device Tech. Labs.(Japan), 4.
Presentation No.: CTuP8B-04 (Invited)

Invited lecture by NTT research group in the session on 2D materials and nanophotonics
The lecture was a review of the novel novel approach to the unmodified Hermite system in photonic crystals, which has been actively studied since the early 2000s, and was very informative. Especially interesting were the latest results (K. Takata, et. al., Phys. Rev. A 105, 013523 (2022)) and the report on nano-laser injection locking (N. Takemura, et. al., Sci. Rep. 11, 8587 (2021)). In the lecture, the WGM system was also discussed, and I felt that there is a possibility of symmetry breaking in the gain and non-linear loss that we are currently calculating in our laboratory.

Title: A Novel Ultra-high Q Buckle-free Large Silica Rib Microdisk with SubMicron Thickness
Author: Shahin Honari1, Tao Lu1
Affiliations: 1. University of Victoria (Canada)
Lecture Number: CThA8C-01

This is a lecture on the fabrication of disk resonators by the research group of the University of Victoria (Canada). The content was a report on the fabrication of disk resonators by chemical mechanical polishing (S. Honari, et. al., Appl. Phys. Lett. 119, 031107 (2021)) and its follow-up report. The follow-up paper, which was the first one to be presented, was about dispersion control by creating a buckling-free rib structure at the outer edge of the disk. After the lecture, we had a brief discussion and found out that they are aiming at sensing in the visible light band and in water in the future. He also shared detailed information such as the thickness of the thermally oxidized silica film of 4 μm without distortion even if the disk diameter is as large as 1 mm, the silica particle size during CMP, and the surface roughness after polishing. In addition, the effect of water on the Q-value was also briefly investigated, and it was interesting to note that there was a threefold difference between the resonator with and without annealing.

Title: Temporal Solitons in Coherently driven Active Fiber Resonators
Author: Francois Leo1
Affiliations: 1. Universite libre de Bruxelles (Belgium)
Presentation No.: CTuA1B-01 (Invited)

A report of active soliton generation by changing the detuning of a fiber laser as in soliton generation using a small optical resonator. Originally a collaborator with Stéphane Coen and Miro Erkintalo. It should be noted that the Er-doped fiber in the fiber ring is operated below the oscillation threshold and the induced emission does not affect the soliton stability, although this effect was not directly mentioned. I missed this because it was allocated to the solid state lasers session.

3. at the end

I noticed that many researchers related to microcomputers and fibercomputers attended the session on 2-D materials and unused materials, and I felt the high level of attention to this topic.
Although it was midsummer, it was cool enough in the mornings and afternoons that long sleeves were necessary when the wind blew, and above all, the temperature was pleasant.