Monolithically integrated electro-optic modulator fabricated on lithium niobate on insulator by photolithography assisted chemo-mechanical etching

Abstract

Integrated electro-optic (EO) modulators are one of the building blocks of photonic integrated circuits. Here, we design and fabricate an EO Mach–Zehnder waveguide modulator on lithium niobate on insulator using photolithography assisted chemo-mechanical etching technology. We optimize the performance of multi-mode interferometer which serves as the 3 dB splitter as well as that of the inverse taper to achieve efficient fiber-waveguide coupling, resulting in a fiber-to-fiber insert loss of 7.6 dB for the fabricated device, with a half wave voltage (HWV) (Vπ ) of 0.84 V and a HWV-length product (Vπ × L) of 3.4 V cm. The all-optical-lithography fabrication approach holds the promising potential for mass production of EO modulators of cost-effectiveness and low Vπ .