We present a broadband integrated photonic polarization splitter and rotator (PSR) using adiabatically tapered coupled waveguides with subwavelength grating (SWG) claddings. The PSR adiabatically rotates and splits the fundamental transverse-magnetic (TM0) input to the fundamental transverse-electric (TE0) mode in the coupler waveguide, while passing the TE0input through the same waveguide. The SWGs work as an anisotropic metamaterial and facilitate modal conversions, making the PSR efficient and broadband. We rigorously present our design approaches in each section and show the SWG effect by comparing with and without the SWG claddings. The coupling coefficients in each segment explicitly show a stronger coupling effect when the SWGs are included, confirmed by the coupled-mode theory simulations. The full numerical simulation shows that the SWG-PSR operates at 1500–1750 nm (≈250 nm) wavelengths with an extinction ratio larger than 20 dB, confirmed by the experiment for the 1490–1590 nm range. The insertion losses are below 1.3 dB. Since our PSR is designed based on adiabatical mode evolution, the proposed PSR is expected to be tolerant to fabrication variations and should be broadly applicable to polarization management in photonic integrated circuits.
We design and experimentally demonstrate a polarizing beam splitter (PBS) on a silicon-on-insulator (SOI) platform based on an asymmetric directional coupler. The asymmetric directional coupler consists of a regular strip waveguide and a sub-wavelength grating (SWG) waveguide. Engineering the waveguide dispersion via SWG, the phase-matching condition can be satisfied for TM polarization over a broad bandwidth when the waveguide dimensions are optimized. The coupling region of the realized PBS is ∼7.2 µm long. For the fabricated PBS, the polarization extinction ratio (PER) is 10–45 dB and the insertion loss is 0.3–2.5 dB for TM polarization while the PER is 14–22 dB and the insertion loss is < 0.6 dB for TE polarization when operating in the wavelength range of 1460 –1610 nm.
more » « less- PAR ID:
- 10138708
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- OSA Continuum
- Volume:
- 3
- Issue:
- 3
- ISSN:
- 2578-7519
- Format(s):
- Medium: X Size: Article No. 560
- Size(s):
- Article No. 560
- Sponsoring Org:
- National Science Foundation
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