Title :
ARROW-type vertical coupler filter: design and fabrication
Author :
Chu, S.T. ; Pan, W. ; Sato, S. ; Little, Brent E. ; Kaneko, T. ; Kokubun, Y.
Author_Institution :
3D Microphotonics Project, Kanagawa Acad. of Sci. & Technol., Kawasaki, Japan
fDate :
4/1/1999 12:00:00 AM
Abstract :
Vertical coupler filters (VCF) exhibiting narrow bandwidth and low sidelobe levels have been designed and demonstrated. Narrow bandwidth filter response is achieved due to the strong asymmetry between the waveguides of the filter and the nondispersive characteristics of the anitresonant reflecting optical waveguide (ARROW) structure. An ARROW-type VCF with a conventional parallel coupled directional coupler configuration with a full width at half-maximum (FWHM) of 1.36 nm and a maximum sidelobe level of -8.5 dB was fabricated using a compound glass consisting of SiO2 and SiO2-Ta2O5 . The filter sidelobe levels were then further suppressed by using an X-crossing arrangement to provide coupling strength apodization along the device. The sidelobe levels of this modified X-crossing filter were suppressed to below -23 dB and the measured FWHM was 3.9 nm. The central wavelength of the reported filters are in the 1.55 μm region. The measured results are in good agreement with theoretical results from an analysis procedure that combines the coupled mode theory with the finite difference complex mode solver
Keywords :
coupled mode analysis; optical design techniques; optical directional couplers; optical fabrication; optical images; optical waveguide filters; optical waveguide theory; symmetry; 1.55 mum; ARROW; ARROW-type vertical coupler optical filter design; ARROW-type vertical coupler optical filter fabrication; SiO2; SiO2-Ta2O5; anitresonant reflecting optical waveguide; compound glass; conventional parallel coupled directional coupler configuration; coupled mode theory; coupling strength apodization; finite difference complex mode solver; low sidelobe levels; maximum sidelobe level; modified X-crossing filter; narrow bandwidth; narrow bandwidth filter response; nondispersive characteristics; sidelobe levels; strong asymmetry; Bandwidth; Directional couplers; Fabrication; Laboratories; Optical filters; Optical waveguides; Planar waveguides; Semiconductor waveguides; Wavelength division multiplexing; Wavelength measurement;
Journal_Title :
Lightwave Technology, Journal of
