Monolithically integrated ultra-wideband photonic receiver on thin film lithium niobate.

As the demand for data capacity in wireless networks and mobile communications continues to grow, they are moving toward higher carrier frequencies and wider modulation bandwidths. Unfortunately, electronic device performance degrades in association with increased frequency and modulation bandwidths, which inhibits the application of conventional microwave architectures, particularly in the millimeter wave and terahertz regimes. Alternatively, microwave photonic systems address these challenges by offering device and system performance with exceptionally higher operational bandwidths. The challenge, however, is the ability to monolithically integrate both electronic and photonic devices into functional components that provide ultra-wideband performance up into the millimeter wave and terahertz regions. In particular, such integration remains a major technical challenge due to the high dielectric permittivity of commonly used material platforms for photonic integrated circuits, such as silicon, indium phosphide, and lithium niobate. In this paper, we present a photonic receiver consisting of a broadband antenna and a low-drive-voltage modulator monolithically integrated on thin-film lithium niobate with a quartz handle. A free-space data link is demonstrated, achieving data rates up to 2.7 Gbps using quadrature amplitude modulation, with error vector magnitude as low as 3%. This work demonstrates the potential of thin-film lithium niobate for high-frequency, monolithically integrated radiofrequency and photonic devices to enable ultra-wideband millimeter wave-to-terahertz communication systems.