Abstract: The present invention discloses a TMOS based on slab PhCs with a high DOP and a large EXR, which comprises an upper slab PhC and a lower slab PhC; the upper slab PhC is called as a first square-lattice slab PhC with a TE bandgap, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single first flat dielectric pillar and a background dielectric, the first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or a high-refractive-index flat film, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, wherein the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single second flat dielectric pillar and a background dielectric, and a normalized operating frequency of the TMOS with high DOP and large extinction ratio is 0.252 to 0.267.

Abstract: The present invention discloses a PIOS with a high extinction ratio based on slab PhCs which comprises an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating square pillar, a single first flat dielectric pillar and a background dielectric; the first flat dielectric pillar includes a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or a high-refractive-index flat films, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of said second square-lattice slab PhC includes a high-refractive-index rotating square pillar, a single second flat dielectric pillar and a background dielectric is a low-refractive-index dielectric; and an normalized frequency of the optical switch is 0.41 to 0.4167.