Design of Waveguide Polarization Convertor Based on Asymmetric 1D Photonic Crystals

Abstract

Photonic crystals possess metastructures with a unique dispersion relation. An integrated optical circuit plays a crucial role in quantum computing, for which miniaturized optical components can be designed according to the characteristics of photonic crystals. Because the stable light transmission mode for a square waveguide is transverse electric or transverse magnetic polarization, we designed a half-waveplate element with a photonic crystal that can rotate the polarization direction of the light incident on a waveguide by 90°. Using the dispersion relation of photonic crystals, the polarization rotation length and the optical axis’s angle of deviation from the electric field in the eigenmode can be effectively calculated. Polarization rotators designed on the basis of photonic crystal structures can effectively reduce the insertion loss of components and exhibit favorable polarization rotation performance.

Towards the on-chip realization of polarization encoded qubits

“…Square cross-section vortex fibers for THz orbital angular mode multiplexing have also been demonstrated [20]. Other recent work in square symmetry integrated photonics include a design of an array waveguide [21], a design for very low index geometry invariant waveguides [22] and designs for polarization rotators [23,24].…”

Design of Reflective Polarization Rotator in Silicon Waveguide

“…The maximum reflectivity is around −2.5 dB (56%). We recently reported two novel transmission-type polarization rotators based on shifted circular and rectangular air holes in a silicon waveguide [ 18 , 19 ], which could be used in quantum computing as the logic gates. The device length can be shorter than the L-shaped or trench waveguides [ 20 , 21 , 22 , 23 ] due to the higher birefringent effect formed by photonic crystals.…”