Title :
A very short planar silica spot-size converter using a nonperiodic segmented waveguide
Author :
Spuhler, Michael M. ; Offrein, Bert J. ; Bona, Gian-Luca ; Germann, Roland ; Massarek, Ilana ; Erni, Daniel
Author_Institution :
Lab. for Electromagn. Fields & Microwave Electron., Eidgenossische Tech. Hochschule, Zurich, Switzerland
fDate :
9/1/1998 12:00:00 AM
Abstract :
To reduce the coupling loss of a fiber-to-ridge waveguide connection, a planar silica spot-size converter for a wavelength of 1.55 μm is implemented in the form of a nonperiodic segmented waveguide structure with irregular tapering. A simple single-step lithography process is sufficient for the fabrication of the planar structures. An evolutionary algorithm has been successfully applied for the optimization. The simulated results obtained with a three-dimensional (3-D) finite difference beam propagation method (FD-BPM) program are compared with measurements of implemented couplers, showing very good agreement. A waveguide-to-fiber coupling efficiency improvement exceeding 2 dB per converter is shown. Structures obtained with this approach are very short (~140 μm) and simple to integrate on the same wafer with other planar structures such as phased arrays or ring resonator structures
Keywords :
finite difference methods; optical communication equipment; optical couplers; optical fibre couplers; optical planar waveguides; optical waveguide theory; optimisation; photolithography; ridge waveguides; silicon compounds; 1.55 mum; 3D finite difference beam propagation method; SiO2; coupling loss; evolutionary algorithm; fiber-to-ridge waveguide connection; irregular tapering; nonperiodic segmented waveguide; nonperiodic segmented waveguide structure; optimization; phased arrays; planar silica spot-size converter; planar structures; ring resonator structures; single-step lithography process; very short planar silica spot-size converter; waveguide-to-fiber coupling efficiency; Couplers; Evolutionary computation; Fabrication; Finite difference methods; Lithography; Optical ring resonators; Phased arrays; Planar waveguides; Silicon compounds; Wavelength converters;
Journal_Title :
Lightwave Technology, Journal of
