Broadband Y-branch electro-optic GaAs waveguide interferometer for 1.3 μm

Abstract
Electro‐optic Mach–Zehnder rib waveguide interferometers with low loss Y branches and Schottky barrier electrodes have been fabricated in n/n+‐GaAs by reactive ion etching. With antireflection coating and optimized Y branches device losses of the interferometers at 1.3 μm were as low as 4 dB. In a push‐pull configuration drive voltages of only 13 V suffice to attain a modulation depth of 12.7 dB. The optical signal bandwidth of these interferometers was measured to exceed 4.5 GHz.