Biopolar-voltage-controlled optical switch fabricated on Z-cut Ti. LiNbO₃ intersecting waveguides

A new optical switch is proposed in which attention is paid to the behavior of the guided wave at the crossing of an intersecting waveguide. Design and fabrication of an optimal configuration were carried out at a wavelength of 1.3 μm. For the analysis of the operating mechanism and the optimum design, a waveguide analysis method based on the Fourier transform has been used. By means of the electrodes formed via a buffer layer on a Z-cut Ti:LiNbO₃, a bipolar optical switch was fabricated in which switching is possible in both the positive and negative polarities. This switch has a low loss and low crosstalk if the intersection length is short. If the device length is increased for reduction of the operating voltage, other characteristics are degraded.