Compact topological polarization beam splitter based on all-dielectric fishnet photonic crystals

Conventional polarization beam splitters (PBSs) suffer energy loss and signal distortion due to backscattering caused by disturbances. Topological photonic crystals provide backscattering immunity and anti-disturbance robustness transmission owing to the topological edge states. Here, we put forward...

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Bibliographic Details
Published in:Optics letters 2023-06, Vol.48 (12), p.3171-3174
Main Authors: Su, Ya, Qin, Meibao, Ouyang, Mingyu, Lei, Linlin, He, Lingjuan, Wang, Tongbiao, Yu, Tianbao
Format: Article
Language:English
Subjects:
Backscattering
Beam splitters
Bends
Communications systems
Crystal defects
Frequency ranges
Integrated circuits
Optical communication
Photonic band gaps
Photonic crystals
Polarization
Refractivity
Signal distortion
Topology
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Summary:Conventional polarization beam splitters (PBSs) suffer energy loss and signal distortion due to backscattering caused by disturbances. Topological photonic crystals provide backscattering immunity and anti-disturbance robustness transmission owing to the topological edge states. Here, we put forward a kind of dual-polarization air hole-type fishnet valley photonic crystal with a common bandgap (CBG). The Dirac points at the K point formed by different neighboring bands for transverse magnetic and transverse electric polarizations are drawn closer via changing the filling ratio of the scatterer. Then the CBG is constructed by lifting the Dirac cones for dual polarizations within a same frequency range. We further design a topological PBS using the proposed CBG via changing the effective refractive index at the interfaces which guide polarization-dependent edge modes. Based on these tunable edge states, the designed topological PBS (TPBS) achieves efficient polarization separation and is robust against sharp bends and defects, verified by simulation results. The TPBS's footprint is approximately 22.4 × 15.2 , allowing high-density on-chip integration. Our work has potential application in photonic integrated circuits and optical communication systems.
ISSN:0146-9592
1539-4794
DOI:10.1364/OL.492427