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We present polarization-free Bragg filters having subwavelength gratings (SWGs) in the lateral cladding region. This Bragg design expands modal fields toward upper cladding, resulting in enhanced light interaction with sensing analytes. Two device configurations are proposed and examined, one with index-matched coupling between transverse electric (TE) and transverse magnetic (TM) modes and the other one with hybrid-mode (HM) coupling. Both configurations introduce a strong coupling between two orthogonal modes (either TE-TM or HM1-HM2) and rotate the polarization of the input wave through Bragg reflection. The arrangements of SWGs help to achieve two configurations with different orthogonal modes, while expanding modal profiles toward the upper cladding region. Our proposed SWG-assisted Bragg gratings with polarization independency eliminate the need for a polarization controller and effectively tailor the modal properties, enhancing the potential of integrated photonic sensing applications.
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Photonic Bragg gratings with cladding asymmetry for polarization independent and rotation filter
We present a single-etched polarization-independent Bragg filter using cladding asymmetry. An air cladding strongly couples TE and TM modes, rotating its polarization status and achieving polarization-insensitive Bragg reflection at the average of both Bragg wavelengths
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- Award ID(s):
- 1930784
- PAR ID:
- 10468031
- Publisher / Repository:
- Optica Publishing Group
- Date Published:
- Page Range / eLocation ID:
- JW2A.112
- Format(s):
- Medium: X
- Location:
- San Diego, CA
- Sponsoring Org:
- National Science Foundation
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