Polarization rotator Bragg grating assisted wavelength selective polarization alignment

TL;DR

This paper demonstrates a device that combines polarization rotation and wavelength selection using Bragg gratings in waveguides, achieving polarization alignment and wavelength filtering in a compact integrated structure.

Contribution

The work introduces a novel integrated device that performs both polarization alignment and wavelength selection using Bragg gratings and mode conversion in waveguides.

Findings

Effective polarization rotation achieved with Bragg gratings.

Unwanted mode excitation minimized with curved waveguides.

Polarization aligned wavelength peaks observed experimentally.

Abstract

A device performing both the polarization-alignment and the wavelength selection is demonstrated by fabricated device. Waveguides incorporating Bragg gratings for polarization rotation and mode conversion having different widths are placed near to each other. For the polarization rotation, experimental results show that the field strength ratio in the two waveguides defines the diffraction coupling coefficient and excitation strength of unwanted modes. The excitation of unwanted mode is reduced, when a large radius short curved waveguide is used for input/output waveguides as shown in the experiment. Polarization aligned wavelength peaks were observed at the backward drop port in the experiment.