Two-dimensional photonic crystal logic equivalence gate based on auto-collimation interference effect

Abstract

Provided is a two-dimensional photonic crystal logic equivalence gate based on an auto-collimation interference effect. The two-dimensional photonic crystal logic equivalence gate comprises a tetragonal lattice photonic crystal which has the auto-collimation interference effect; three line defects serving as three beam splitters S1, S2 and S3 are made inside the photonic crystal and arranged in the auto-collimation beam propagation direction; the distance between the beam splitter S1 and the beam splitter S2 is delta l1=12a, and the distance between the beam splitter S2 and the beam splitter S3 is delta l2=25a, wherein a is a lattice constant of the photonic crystal; the photonic crystal is internally provided with three incident ports and one output port, and the three incident ports are two input beam ports and one reference light port. The phase difference between two input beams is adjusted by adjusting the defect column radius and the light path difference between the two input beams, and the two input beams achieve the logical function through destructive interference or destructive interference. The logic equivalence gate is not limited by physical boundaries in traditional waveguide and has better adaptability.

Description

technical field [0001] The invention relates to a two-dimensional photonic crystal logical XOR gate based on self-collimation interference effect, and belongs to the technical field of physical optics photonic crystals. Background technique [0002] Photonic crystals are made of dielectric materials with different dielectric constants to form a periodic structure in space. When light propagates in it, it is modulated to form a photonic band structure. Under the condition of a suitable lattice constant and dielectric constant ratio, a photonic band appears. Light with a frequency that falls within the photonic band gap cannot propagate. Photonic crystals limit the transmission direction of light through the band gap so as to artificially control the transmission direction of light for light guide. There are anomalous dispersion effects in photonic crystals, including negative refraction, self-collimation and superprism effects. In the self-collimation effect, photonic cryst...

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Problems solved by technology

[0005] Aiming at the problem that the traditional optical switch is limited by the physical boundary in the waveguide, the present invention proposes a two-dimensional photonic crystal logic based on the self-collimation interference effect that can avoid being limited by the physical boundary in the waveguide and make the incident beam transmit along a specific direction NOR gate

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