Title :
A Novel Optical Coupler Design With Graded-Index Photonic Crystals
Author :
Kurt, Hamza ; Citrin, D.S.
Author_Institution :
Inst. d´´Optique, Palaiseau
Abstract :
We explore an efficient method to couple light from a dielectric medium into a two-dimensional photonic-crystal waveguide (PCW). This is achieved by inserting a graded-index photonic crystal (PC) between a dielectric waveguide and a conventional PCW obtained by removing one row of air holes along the TK direction in a triangular-lattice PC. Effective mode transformation is achieved with a spot-size conversion ratio of 12:1. The low transmission efficiency (30%) that occurs in a direct coupling from dielectric waveguide into the PCW is raised to ~80% (0.98 dB) over a broad frequency range. Further improvements for nearly perfect transmission appear to be feasible.
Keywords :
gradient index optics; light transmission; optical couplers; optical design techniques; optical waveguides; photonic crystals; dielectric medium; dielectric waveguide; graded-index photonic crystal; optical coupler; spot-size conversion ratio; transmission efficiency; triangular-lattice photonic-crystal; two-dimensional photonic-crystal waveguide; Coupling circuits; Dielectric losses; Lattices; Optical beams; Optical coupling; Optical design; Optical losses; Optical waveguides; Personal communication networks; Photonic crystals; Coupling losses; graded-index photonic crystals (GRIN PCs); photonic integrated circuits;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2007.903859
