Title :
Fabrication of sidelobe-suppressed InP-InGaAsP vertical coupler optical filter using pair grating structure
Author :
Kim, Dug-Bong ; Park, Chan-Yong ; O, Beom-Hoan ; Kim, Hong-Man ; Yoon, Tae-Hoon
Author_Institution :
Optoelectron. Sect., ETRI, Taejon, South Korea
Abstract :
In this letter, we report -19-dB suppression of sidelobes in a grating-assisted codirectional coupler (GACC) optical filter, which is the lowest to the best of our knowledge. Pair grating structures has been employed to control the coupling strength with a raised cosine functional form. A unit pair grating is composed of two unit conventional gratings and the fundamental period of pair gratings is fixed at 2/spl Lambda/, where /spl Lambda/ is the grating period of conventional GACC filter. The distance between the two gratings inside a pair grating is linearly shifted to control the coupling strength. This structure provides a spatially weighted coupling strength without any change of averaged effective optical index or propagation constant.
Keywords :
III-V semiconductors; diffraction gratings; gallium arsenide; gallium compounds; indium compounds; integrated optics; optical communication equipment; optical directional couplers; optical fabrication; optical waveguide filters; InP-InGaAsP; averaged effective optical index; coupling strength; grating period; grating-assisted codirectional coupler optical filter; linearly shifted; pair grating structure; pair grating structures; propagation constant; raised cosine functional form; sidelobe-suppressed InP-InGaAsP vertical coupler optical filter; spatially weighted coupling strength; unit pair grating; Gratings; Optical coupling; Optical crosstalk; Optical device fabrication; Optical filters; Optical polarization; Optical waveguides; Propagation constant; Refractive index; Wavelength division multiplexing;
Journal_Title :
Photonics Technology Letters, IEEE
