https://doi.org/10.1140/epjp/s13360-022-03600-y
Regular Article
True-time tunable and spectrally-isolated dispersive wave generation by manipulating thermo-optic birefringence of lithium niobate on insulator waveguide
1
Centre for Optical and Electromagnetic Research, College of Optical Science and Engineering, National Engineering Research Center for Optical Instruments, Zhejiang University, 310058, Hangzhou, China
2
Ningbo Research Institute, Zhejiang University, 315100, Ningbo, China
b
zhe_kang@zju.edu.cn
d
sailing@zju.edu.cn
Received:
30
May
2022
Accepted:
15
December
2022
Published online:
11
January
2023
Dispersive wave emission from a high-order dispersion perturbed soliton during the supercontinuum generation can efficiently and directionally transfer the soliton pump energy to the desired wavelength regime, which has a localized spectral structure and maintains the coherence of pump. However, it remains challenging to tune the central wavelength of dispersive wave in a true-time manner because conventional tuning methods depend on the lithography control of the waveguide geometry. In this work, we numerically show that manipulating the thermo-optic birefringence of a thin-film lithium niobate on insulator (LNOI) waveguide, the spectrally-isolated dispersive wave induced by a mode hybridization effect can be thermally tuned. The method is realized in a single suspended LNOI ridge waveguide with thermo-electrodes loaded, regardless of massed waveguide arrays with different geometries and many times of edge-coupling. We show that the mode hybridization dispersive wave (MH-DW) presents a distinguishable isolated spectrum and a broad tuning range up to 200 nm within the temperature of 25 to 500 °C, which is 15 folds larger than that of the conventional dispersive wave (C-DW). Furthermore, the spectrum intensity of the MH-DW can be ~ 20 dB larger than that of the C-DW. We believe this work opens an avenue to true-time tunable spectrum isolation and enhancement in chip-scale supercontinuum generation and its potential applications in spectroscopy at highly targeted frequencies, narrow-band frequency-swept sources, and spectrally-isolated frequency combs generation, etc.
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