Loss reduction of silica-based 8 * 8 optical matrix switch by optimizing waveguide crossings using WFM method

Abstract

We designed waveguide crossings using the wavefront matching method to reduce the excess loss of a silica-based optical 8 × 8 matrix switch. We fabricated the switches using silica-based planar lightwave circuit (PLC) technology and confirmed that the excess loss of our designed waveguide crossings was lower than that of conventional crossings by 0.3dB. The average insertion loss of the fabricated switch including fiber-coupling loss was 1.7dB, which is the lowest value yet reported for a PLC-based switch. The designed waveguide crossings are practically useful for improving the performance of PLC switches with a large number of crossings.