Mach–Zehnder Interferometer-Type Photonic Switches Based on Epitaxially Grown Lanthanum-Modified Lead Zirconate Titanate Films

We present a simple 2×2 port Mach-Zehnder (MZ) interferometer-type photonic switch with multimode interference (MMI) 3-dB couplers using epitaxially grown lanthanum-modified lead zirconate titanate (PLZT) films. The MZ-type MMI PLZT photonic switch with 8-μm-gap coplanar electrodes exhibits a low half-wave voltage of 4.8 V with an extinction ratio of 28 dB for a 2 mm active-region length. An optical insertion loss for the presented switch is measured as 2-3 dB that excluded the coupling losses in lensed fibers for a 6.5-mm-long device.