Title :
A broad-band waveguide grating coupler with a subwavelength grating mirror
Author :
Cheben, P. ; Janz, S. ; Xu, D.-X. ; Lamontagne, B. ; Delage, A. ; Tanev, S.
Author_Institution :
Inst. for Microstruct. Sci., Nat. Res. Council of Canada, Ottawa, Ont., Canada
Abstract :
A new diffractive device for light coupling between a planar optical waveguide and free space is proposed. The device utilizes a second-order waveguide grating to diffract the fundamental waveguide mode into two free propagating beams and a subwavelength grating (SWG) mirror to combine the two free propagating beams into a single beam. The finite-difference time-domain (FDTD) simulations show that the SWG mirror improves the coupling efficiency of the waveguide fundamental mode into the single out-coupled beam from about 30% to 92%. A high efficiency (>90%) is predicted for a broad wavelength range of 1520-1580nm. The proposed device is compact (/spl sim/80 μm in length) and it eliminates the need for blazing the waveguide grating.
Keywords :
diffraction gratings; finite difference time-domain analysis; light diffraction; mirrors; optical couplers; optical planar waveguides; 1520 to 1580 nm; 80 mum; broad-band grating coupler; diffractive device; finite-difference time-domain simulations; free propagating beams; free space; fundamental waveguide mode; light coupling; light diffraction; planar optical waveguide; second-order waveguide grating; single out-coupled beam; subwavelength grating mirror; waveguide grating coupler; Diffraction gratings; Finite difference methods; Mirrors; Optical coupling; Optical devices; Optical diffraction; Optical propagation; Optical waveguides; Reluctance generators; Time domain analysis; Finite-difference time-domain; silicon-on-insulator (SOI) waveguides; subwavelength grating; waveguide grating coupler;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2005.860037
