Electro-optic integration of embedded electrodes and waveguides in LiNbO₃ using a femtosecond laser

We describe the fabrication of a Mach-Zehnder optical modulator in LiNbO₃ by femtosecond laser micro-machining, which is composed of optical waveguides inscripted by a femtosecond laser and embedded microelectrodes subsequently fabricated using femtosecond laser ablation and selective electroless plating. A half-wave voltage close to 19 V is achieved at a wavelength of 632.8 nm with an interaction length of 2.6 mm. This simple and cost-effective technique opens up new opportunities for fabricating integrated electro-optic devices.