Two-dimensional photonic crystal slabs as a tunable polarization mode converter

Two dimensional photonic crystal slabs with elliptical holes exposed to the normal incident laser light are proposed and designed as a tunable broadband polarization rotator. The photonic crystal electric field mode due to the eccentricity and orientation of the holes will provide a mean to exchange power between two orthogonal polarization states. Around guided resonance wavelengths of photonic crystals with 45° oriented elliptical holes, 20% polarization mode conversion is achieved. By tuning of the difference of the two radii of the elliptical holes we are able to span a bandwidth of 130 nm and 70 nm around wavelengths of 1445 nm and 1650 nm. The unique properties of these devices such as ease of engineering and simplified light coupling scheme will make them a promising polarization mode converter in high speed polarization-multiplexed optical transmission systems.