Developments in thin-film lithium niobate modulators for low Vπ, small profile and integrated antennas (Conference Presentation)

This paper presents an overview of the state-of-the-art in high-performance electro-optic modulators (EOM) based on thin-film lithium niobate on insulator (TFLNOI) material platform. By leveraging the advantage of capacitive loaded traveling wave electrodes (CL-TWEs) on a quartz handle, it is possible to engineer a modulator with low radio frequency (RF) loss and broadband index matching, expanding significantly the 3-dB limits of device. Herein we present the design, fabrication, and experimental demonstration of a Dual Output Mach-Zehnder Modulator (DO-MZM) with a 1V drive voltage (V_<i>&pi;</i>), 3-dB bandwidth around 125GHz, and over 40dB extinction ratio. The dual output architecture, when used with a balanced photodetector (PD), can reject common mode noise resulting from Relative Intensity Noise (RIN) in a microwave photonic link (MPL) to the point where it can become shot noise limited. Along with this development, we also experimentally demonstrate a compact sub-1 V<i>_&pi;</i> phase modulator using folded CL-TWEs. Furthermore, based on the high modulation efficiency and high bandwidth modulator design, we have designed, fabricated, and characterized a monolithic ultra-wideband antenna coupled photonic receiver, device that performs direct free space RF signal-to-optical conversion without the support of electronic components.