Photonic crystal waveguide inlet structure

#This patent application claims the benefit of priority under 35 U.S.C. §119 from Korean Patent Application No. 10-2008-0122359 filed on Dec. 4, 2008, the contents of which are incorporated herein by reference.

#1. Field of the Invention

#The present disclosure relates to a photonic crystal waveguide inlet structure for improving coupling efficiency of a strip waveguide and a photonic crystal waveguide.

#The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

#FIG. 1 is a schematic view illustrating structure of a photonic crystal waveguide and a strip waveguide in the related art;

#FIG. 2 is a view illustrating a simulation result with regard to structure of a photonic crystal waveguide and a strip waveguide in the related art;

#Features and advantages of the present invention will be more clearly understood by the following detailed description of the present preferred embodiments by reference to the accompanying drawings. It is first noted that terms or words used herein should be construed as meanings or concepts corresponding with the technical sprit of the present invention, based on the principle that the inventor can appropriately define the concepts of the terms to best describe his own invention. Like reference numerals refer to like elements throughout. Also, it should be understood that detailed descriptions of well-known functions and structures related to the present invention will be omitted so as not to unnecessarily obscure the important point of the present invention.

#Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

#A photonic crystal waveguide according to the present invention includes photonic crystals and a waveguide. In the photonic crystals, air holes are arranged in a triangle lattice shape in a dielectric. The waveguide is formed by removing a line of the air holes arranged in the photonic crystals. A mode in which light travels at a strip waveguide is different from a mode in which light travels at the photonic crystal waveguide, and mismatch of modes occurs in a region where the two waveguides contact each other. This mismatch of the modes causes coupling loss. According to the present invention, the structure of the region where the two waveguides contact each other is modified to provide a hybrid shape region between the strip waveguide and the photonic crystal waveguide, thereby providing a structure minimizing the coupling loss.