Greatly enhanced electro-optic modulation efficiency in titanium in-diffusion PIN–PMN–PT waveguide

Abstract

Electro-optic modulators, which convert electrical signals onto the transmission light, are key devices in electro-optic modulating systems. Modulation efficiency is one of the most important parameters of an electro-optic modulator, which directly determines the footprint and power consumption of the device. Generally, modulation efficiency strongly depends on the electro-optic response of the crystal. The Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) single crystal with giant electro-optic coefficient (γc) and high transparency indicates the potential to achieve greatly enhanced modulation efficiency. In this study, a prototype PIN–PMN–PT phase modulator was fabricated based on a titanium (Ti) in-diffusion waveguide, which is reported for the first time. The influences of titanium in-diffusion on the composition and domain structure of the PIN–PMN–PT single crystal were studied by transmission electron microscopy (TEM) and piezoelectric force microscopy (PFM), respectively. Finally, a half-wave voltage (Vπ) of 2.3 V was obtained using a device with 6-mm-long (L) electrodes. Furthermore, the electro-optic modulation efficiency (VπL) was calculated as 1.38 V·cm, which was approximately one order of magnitude lower than that of commercial lithium niobate (LiNbO3, LN) phase modulators. Such enhanced modulation efficiency indicates more compact device and lower power consumption, which is of great significance for electro-optic modulation systems used in micro-fiber gyroscope, integrated photonic devices, etc.

Keywords

• pb(in1/2nb1/2)o3–pb(mg1/3nb2/3)o3–pbtio3 (pin–pmn–pt) single crystal
• titanium (ti) in-diffusion
• waveguide
• electro-optic modulator