On-Chip Etchless and Tunable Silicon Nitride Waveguide Mode Converter Based on Low-Loss Phase Change Material
Year: 2025
Type: article
Abstract: The development of reconfigurable photonic integrated circuits (PICs) demands photonic devices with high-efficiency tuning capabilities, yet conventional thermo-optic and electro-optic methods suffer from limited index modulation and excessive power consumption. To overcome these limitations, we propose an etchless and tunable silicon nitride waveguide mode converter based on low-loss phase change material, antimony triselenide (Sb2Se3). By depositing an Sb2Se3 layer on the silicon nitride wafer and using a laser-induced phase transition technique, we can write and erase the waveguide structure in the phase change wafer without waveguide etching, where the input/output waveguide is a strip waveguide and the conversion region is built using a tilted subwavelength grating structure. From the results, the obtained TE0-TE1 mode conversion efficiency, crosstalk, and insertion loss are higher than 96%, lower than −16 dB, and lower than 0.4 dB at a wavelength of 1.55 µm, respectively. The proposed device enables post-fabrication tuning of the grating duty cycle, allowing working wavelength adjustment for the same device. Furthermore, the device exhibits scalability to other higher-order mode conversions (e.g., TE0-TE2). Consequently, we expect that such devices could have important uses in programmable and multifunctional PICs.
Source: Photonics
Authors: Tianman Shu, Yuexiang Guo, Shengxiong Lai, Lun Zhang, Yin Xu, Hualong Bao
Language: English
Topic: Photonic and Optical Devices
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
Awards: G1062796159, G7628705990
OpenAlex ID: W4414355219