Design Of Polarization Rotator Research Articles

High-efficiency and broadband photonic polarization rotator based on multilevel shape optimization.

We report on a novel photonic polarization rotator design obtained by multilevel shape optimization. The numerical method consists of a topological optimization scheme, improving iteratively the efficiency of the component by modifying its shape on two discrete levels along the etching direction. We numerically show that, compared to state-of-the-art single-level shape optimization, the performances can be drastically improved for a given device length. Next, the polarization conversion efficiency can be further improved up to a computed value of 98.5% with less than 0.35dB insertion losses on a 100nm bandwidth for a 6 μm×1 μm footprint.

Design and Analysis of Ultrathin Polarization Rotating Frequency Selective Surface Using V-Shaped Slots

A novel polarization rotator design is demonstrated theoretically as well as experimentally based on frequency-selective surface (FSS). The polarization rotator selectively allows the linearly polarized incident wave to pass through the structure and rotates it by $\text{90}^\circ$ in a given frequency band. The periodic element of the FSS design consists of orthogonally oriented V-shaped slots on two metal sheets with the dielectric substrate separating the sheets. The proposed structure exhibits a relative bandwidth of $\text{8}\%$ (9.76–10.57 GHz) with a maximum insertion loss of 0.5 dB. Copolarized reflection coefficient is less than −10 dB in the same frequency band. The novelties of the structure lie in its reduced thickness ( $\text{0.053}\lambda _o$ ) as well as compact design ( $\text{0.28}\lambda _o$ ) as compared to the existing polarization rotators. A prototype has also been fabricated, and good agreement between the simulated and experimental results is observed.

Compact SOI Polarization Rotator Using Asymmetric Periodic Loaded Waveguides

We demonstrate the design and experimental results of a silicon-on insulator (SOI) polarization rotator design based on asymmetric periodically loaded waveguides. The rotator design features a compact device footprint of 15.78 $\mu\mbox{m}$ , with a measured polarization rotation extinction ratio of 11.8 dB at 1525 nm while maintaining at least 6 dB ER over the entire C-band. The fabrication of this rotator is fully compatible with the standard complementary metal-oxide semiconductor (CMOS) process with a SiO2 top cladding. So far, this is the most compact polarization rotator demonstration utilizing the asymmetric periodically loaded SOI waveguides. However, the device is sensitive to fabrication errors; thus, the performance is limited by the current fabrication technology.

Design of polarization rotators in TE–TM mode conversion optical isolator with Ce:YIG guiding layer

An optical isolator with a (CeY)3Fe5O12 guiding layer employing TE–TM mode conversion was investigated. The optical isolator consisted of a nonreciprocal polarization rotator and a reciprocal polarization rotator. The reciprocal polarization rotator was realized by inserting a polyimide half-wave plate into a groove in the magnetooptic waveguide. Propagation distances required for the nonreciprocal polarization rotator were calculated at a wavelength of 1.55 µm. Diffraction loss due to the insertion of the half-wave plate was also calculated. The reciprocal polarization rotator integrated with a spot-size converter was proposed for suppressing the diffraction loss. By introducing the spot-size converter for an input facet and an output facet of the half-wave plate, a calculated total insertion loss was reduced to 0.22 dB.

Robust Silicon Waveguide Polarization Rotator With an Amorphous Silicon Overlayer

We propose a robust polarization rotator based on the mode-evolution mechanism. The polarization rotation in a silicon wire waveguide is achieved by forming an amorphous silicon (a-Si) overlayer and an SiO2 spacer on top of the waveguide. A strip pattern of a constant width is designed to be etched through the overlayer at a specific angle with respect to the Si waveguide. The asymmetry in the a-Si overlayer affects the waveguide mode by rotating the modal axis. This polarization rotator design is amenable to comparatively simple fabrication compatible with standard silicon photonic processing for integration. The length of the rotation section is 17 μm, and the broadband operation is achieved with a rotation efficiency higher than 90% for a wavelength range exceeding 135 nm. A maximum polarization rotation efficiency of 99.5% is predicted by calculation.

Design of passive polarization rotator based on silica photonic crystal fiber

We propose and analyze a novel (to the best of our knowledge) design of a polarization rotator (PR) based on silica photonic crystal fiber. The proposed design has a rectangular core region with a slanted sidewall. The simulation results are obtained using the full vectorial finite difference method as well as the full vectorial finite difference beam propagation method. The numerical results reveal that the suggested PR can provide a nearly 100% polarization conversion ratio with a device length of 3102 μm.

Beam propagation modeling of polarization rotation in deeply etched semiconductor bent waveguides

A rigorous study of polarization rotation in deeply etched semiconductor optical waveguide bends has been carried out and results are presented, using the finite element-based fully vectorial beam propagation method. It has been shown that by careful adjustment of the waveguide width, the slant sidewalls and the bending radius, a very compact polarization rotator design, only 60 μm long, with extremely low overall loss, and nearly 100% polarization conversion ratio can be achieved.