Photonic-crystal structures with polarized-wave-guiding property and their applications in the mid and far infrared wave bands

Abstract

Photonic crystal (PhC) structures with polarized-wave-guiding property (PhC polarization waveguides) are proposed, demonstrated and applied to construct several new kinds of compact and efficient micro polarization devices in the mid and far infrared wave bands, including TE polarizers, TM polarizers, TE-downward T-shaped polarization-beam splitters (PBSs), TM-downward T-shaped PBSs and lying-T-shaped PBSs. Theoretical models for the operating mechanism of the structures are presented. The polarization devices built as applications of the PhC polarization waveguides are demonstrated by the finite-element method with the dispersion of materials being considered. Furthermore, optimized parameters are obtained by investigating the extinction ratio (EXR), the degree of polarization (DOP) and insertion loss. Moreover, structures based on PhC slabs derived from the 2D ones, together with woodpile PhC covers and substrates are suggested for the 3D version of the proposed devices for implementation. An example of the 3D-version structures shows a performance as good as that of the 2D structure. The devices proposed have relatively wide ranges of operating wavelength. Meanwhile, they are very compact in their structures and convenient for connection or coupling of signals among different optical elements, so they have the potential for wide applications in mid-and-far infrared optical devices or circuits, which are useful in remote sensing, image and vision, positioning and communications with infrared waves. Furthermore, the principle can be applied to build polarizers and PBSs in other wave bands.

Highly Compact Circulators in Square-Lattice Photonic Crystal Waveguides

“…Considering further that PhC of silicon rods in air background has much wider photonic bandgap and thus much better confinement of waves than PhC of air holes in silicon background, we choose to use PhC slabs of silicon rods in air background. For the third direction confinement of waves, we propose using substrates and covers of a few periods of 3D PhCs [2] , e.g., woodpile, opals and Yablonovite. Specifically, metallic-plate cover and substrate can be used in the microwave region.…”

“…9 , the electric field distribution is displayed, showing that the structure operates as a perfect 3D circulator. We point out that the height of the slab can also be optimized to obtain still better performance [2] .…”

Numerical simulation of polarization beam splitter with triangular lattice of multi-walled carbon nanotube arrays

“…With the designed polarization beam splitter [29], two orthogonal polarization states of the signal can be divided into absolutely disparate directions. An appropriate choice of parameters makes it possible to guide the TE polarization in a waveguide [30] and transmit the TM polarization in the crystal for a wavelength range covering several important optical windows (1310 nm and 1550 nm) for optical communications. Furthermore, the splitter can be used in integrated optical field due to its nanoscale dimension.…”

Integrated optical refractometer based on bend waveguide with air trench structure

“…To overcome this problem, several methods have been proposed such as high-index contrast waveguides, photonic-crystal waveguides, corner mirrors waveguides, and metal-insulator-metal (MIM) waveguides. [5][6][7][8] Among these waveguides, the high-index contrast waveguide can have its optical loss controlled using the characteristics of enhanced light confinement because the refractive index contrast between the core and clad layer can control optical characteristics such as light confinement. 8,9 The optical refractometer device depends on the variations of the refractive index.…”