PIERS 2023 Ryo Kanno

2023-08-21 2024-01-23 MatsuyamaHayato

Research

PIERS 2023 Participation Report

3th July - 6th July, Prague Congress Center, Prague ,Czech Republic

Doctoral Course Ryo Kanno

1. participating conferences

Conference: PhotonIcs and Electromagnetics Research Symposium 2023
Dates: July 3, 2023 - July 6, 2023
Location: Prague Congress Center, Prague ,Czech Republic

About PIERS2023

This conference was hosted by Czech Technical University in Prague, Zhejiang University, and The Electromagnetics Academy at Zhejiang University. Since the conference was hosted by Zhejiang University, there were many Asians in the conference, and I saw many Japanese whom I knew. As for the conference, there were many sessions other than nanophotonics, such as quantum optics and microwaves, and many of the sessions were unfamiliar to me. Many of the sessions were unfamiliar to me, but I was able to gain a better understanding of the comprehensive content of the presentations, partly because there were many invited speakers in my own field.

3. presentation by the presenter

Title: SiN/Si Hybrid Integration with Edge Couplers by Butt-coupling
Presenter: Ryo Sugano
Affiliation: Keio University
Presentation No.: 1P4a (13:30, Mon, July 3rd)

Optical integrated circuits have been studied in a variety of materials, taking advantage of CMOS compatibility, which can be fabricated in the same way as electrical circuits. Silicon (Si) is a typical CMOS-compatible material, and active devices such as modulators using PN junctions have been integrated. However, it is an indirect transition semiconductor, which does not allow the fabrication of light sources in the telecommunication wavelength band, and its two-photon absorption makes it difficult to generate effective nonlinear optical effects. Silicon nitride (SiN) is a silicon compound that has recently attracted attention as a material that can effectively generate optical frequency comb, a multi-wavelength, highly repetitive light source. These materials are difficult to propagate effectively only when they are bonded as they are, due to their different waveguide widths and film thicknesses. Therefore, in this study, the coupling efficiency of the inverse-tapered structure in the chip cross-section and butt-coupling was clarified computationally and experimentally. The finite difference time domain method and the eigenmode expansion method were used to optimize the inverse tapered structure. Both the effective refractive index of the waveguide and the mode overlap, which means the overlap of each mode, were found to be important. The maximum coupling efficiency of 96.31 TP3T was achieved by optimizing the waveguide width while taking manufacturing errors into account. The maximum coupling efficiency was 96.31 TP3T when the gap between the chips was filled with various refractive index matching materials.
The efficiency was calculated, and it was found that the coupling efficiency was prevented from decreasing with a refractive index of 1.7 compared to that with an effective refractive index of 1.7. This is thought to be due to the shorter optical path length. These inverse tapered structures were designed and actually bonded to SiN/Si. The coupling efficiency calculated by a rough method was 45.91 TP3T, and 58.81 TP3T by filling with refractive index matching material.

4. presentations attended

Title: Versatile Cavity Solitons for Kerr Frequency Comb Generation
Presenter: Xiaoxiao Xue
Affiliation: Tsinghua University
Presentation No.: 1A4 (10:30, Mon, July 3rd)

A study of the generation of new non-dispersive Nyquist solitons, which are different from conventional zero-dispersive solitons. Dissipative solitons have attracted much attention in recent years because they can be generated on the chip scale by using resonators. The generated conventional solitons, dark pulses (platycons), are supported by a complex balance of several effects including gain, loss, nonlinearity, and dispersion.
The present study uses a fiber ring resonator incorporating a programmable spectral shaper and elbium gain to generate nondispersive Nyquist solitons. In this study, nondispersive Nyquist solitons were generated using a fiber ring resonator with a programmable spectral shaper and erbium gain, which allows arbitrary cavity dispersion and filtering. In addition to being able to be excited without passing through the chaotic region, the nondispersive Nyquist soliton has a flat spectrum and high conversion efficiency.

Title: Heterogeneously Integrated, On-chip, Lasers with Sub-micron Wavelengths for
Quantum Applications
Presenter: Nima Nadar
Affiliation: National Institute of Standards and Technology
Presentation No.: 1P3 (14:45, Mon, July 3rd)

Ta2O5 is an attractive material for various applications because of its low thermo-optic effect and low stress distortion compared to SiN. Ta2O5 is an attractive material for various applications because it can transmit near UV (380 nm~) and has a Q-value up to the sixth power.

Title: Nanowire Photonic Crystal Arrays for Optical Elements in Photonic Integrated
Circuits
Presenter: Hans-Peter Wagner
Affiliation: University of Cincinnati
Presentation No.: 1P3 (15:05, Mon, July 3rd)

A study of nanowire photonic crystal lasers fabricated in InP, a III-V semiconductor. The threshold is lower than that of conventional Si nanowire photonic crystal lasers. The high birefringence of InP makes it suitable for fabrication of micro-sized optical elements, and it can be used as polarization conversion elements and phase delay elements. Furthermore, plasmonic amplification can be achieved by coating them with gold, which is expected to lead to more versatile applications.