Work

Thermally tunable microring resonators based on germanium-on-insulator for mid-infrared spectrometer

Year: 2024

Type: article

Abstract: We present a thermally tunable microring resonator (MRR) implemented on a Ge-on-insulator (Ge-OI) photonic platform tailored for mid-infrared spectrometer applications. Thanks to the favorable thermo-optic effect of Ge, we characterized the optical and thermal properties of the thermally tunable Ge-OI MRR through rigorous optical and thermal numerical analyses. Building upon the simulation, a ring-shaped Au heater was successfully integrated into the Ge-OI MRR that was fabricated by using a direct wafer bonding process, followed by electron-beam lithography and dry etching techniques. Observations via thermo-reflectance microscopy revealed the temperature change within the Ge induced by heat transfer from the applied bias to the Au heater. Notably, the measured temperature change of 17 K at an applied electrical power of 181.7 mW closely aligned with the simulated values. In optical measurement, the heater-integrated Ge-OI MRR exhibited the tunability of 33.7 nm/W (0.36 nm/K) and the loaded Q factor of 21k at 4.2 µm wavelength with no bias. Hence, our demonstration of the Ge-OI tunable ring filter for mid-IR spectrometers could be a promising technology employing photonic integrated circuits for diverse applications in optical communication and spectral sensing.

Source: APL Photonics

DOI: 10.1063/5.0220382

Authors: J. Lim, J. Shim, I. Kim, S. K. Kim, D.-M. Geum, S. Kim

Institutions: Korea Advanced Institute of Science and Technology, Chungbuk National University

Language: English

Topic: Photonic and Optical Devices

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,750

Funder: National Research Foundation of Korea