Mode hybridization analysis in thin film lithium niobate strip multimode waveguides

Abstract Mode hybridization phenomenon in air-cladded X-cut Y-propagating and Z-propagating thin film lithium niobate strip multimode waveguides is numerically studied and a mathematical relation between structural parameters leading to hybrid modes is formulated. Dependence of hybrid modes on waveguide dimensions, sidewall angles and wavelength is also analyzed. The results obtained are used to design lithium niobate on insulator (LNOI) taper for converting fundamental TM mode to higher order TE mode, and an optimum length for achieving a high conversion efficiency of 99.5% is evaluated. Birefringent Y-propagating LN and isotropic Z-propagating LN tapers are compared in terms of length, figures of merit, and fabrication tolerance. Tapers exhibit a broad bandwidth of 200 nm with an extinction ratio less than − 18 dB. The results of mode hybridization analysis are useful in design optimization of adiabatic tapers, tunable time delays, optical interconnects, mode converters and demultiplexers for mode division multiplexing (MDM) applications.

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Lithium Niobate Thin Film Based A3 Mode Resonators with High Effective Coupling Coefficient of 6.72%

2021 IEEE 34th International Conference on Micro Electro Mechanical Systems (MEMS) ◽

10.1109/mems51782.2021.9375462 ◽

2021 ◽

Author(s):

Yi Zhang ◽

Liang Wang ◽

Yang Zou ◽

Qinwen Xu ◽

Jieyu Liu ◽

...

Keyword(s):

Thin Film ◽

Lithium Niobate ◽

Coupling Coefficient ◽

Effective Coupling

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Plasmon-Enhanced Sunlight Harvesting in Thin-Film Solar Cell by Randomly Distributed Nanoparticle Array

Materials ◽

10.3390/ma14061380 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1380

Author(s):

Marwa M. Tharwat ◽

Ashwag Almalki ◽

Amr M. Mahros

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Near Infrared ◽

Structural Parameters ◽

Visible Region ◽

Nanoparticle Array ◽

Solar Energy Harvesting ◽

Infra Red ◽

Crucial Parameter

In this paper, a randomly distributed plasmonic aluminum nanoparticle array is introduced on the top surface of conventional GaAs thin-film solar cells to improve sunlight harvesting. The performance of such photovoltaic structures is determined through monitoring the modification of its absorbance due to changing its structural parameters. A single Al nanoparticle array is integrated over the antireflective layer to boost the absorption spectra in both visible and near-infra-red regimes. Furthermore, the planar density of the plasmonic layer is presented as a crucial parameter in studying and investigating the performance of the solar cells. Then, we have introduced a double Al nanoparticle array as an imperfection from the regular uniform single array as it has different size particles and various spatial distributions. The comparison of performances was established using the enhancement percentage in the absorption. The findings illustrate that the structural parameters of the reported solar cell, especially the planar density of the plasmonic layer, have significant impacts on tuning solar energy harvesting. Additionally, increasing the plasmonic planar density enhances the absorption in the visible region. On the other hand, the absorption in the near-infrared regime becomes worse, and vice versa.

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