SIDELOBE SUPPRESSION OF VERTICAL COUPLER FILTER WITH AN X-CROSSING CONFIGURATION

An antiresonant reflecting optical waveguide (ARROW) type vertical cou pler filter exhibiting low sidelobe charateristics is demonstrated. Th e sidelobe level of the filter has been suppressed by using an X-cross ing arrangement to provide strength apodization along the device. The main sidelobe of the fabricated filter is measured to be less than -17 dB with the central wavelength in the 1.55 mu m region. An analysis p rocedure which combines the coupled mode theory with the finite differ ence mode solver is also presented to efficiently calculate the vertic al coupler filter response.