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

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.