Abstract

Silica-based strictly nonblocking 8×8 matrix switches have thus far been successfully fabricated by integrating 64 thermo-optic (TO) Mach-Zehnder (MZ) switching units on a single Si substrate as shown in Fig. 1.^1,2 The major problem with this type of MZ unit is that the constituent 3-dB couplers must be precisely set at 50% coupling in the waveguide fabrication process. This paper proposes improved MZ geometries for constructing low- crosstalk matrix switches with extremely large fabrication tolerances.

© 1993 Optical Society of America