Low-loss polarization-independent electrooptical switches at λ = 1.3µm

Polarization-independent single-mode optical cross points with low loss have been fabricated for
\lambda = 1.3-\mu
m wavelength. Waveguide design, coupling strength equalization for the two polarizations, fabrication tolerances, and the performance of several Ti:LiNbO
3
directional-coupler switches are presented. Two 2 × 2 switches have been made with fiber pigtails. The switches have an insertion loss of ∼3- and
\sim-14
-dB crosstalk isolation with a 70-V operating voltage. A 4 × 3 switch had similar performance but higher insertion loss.