On-chip microwave photonic sensor featuring silicon-polymer hybrid subwavelength grating waveguide and bowtie antenna (Conference Presentation)

Abstract

A photonic microwave sensor based on electro-optic (EO) polymer infiltrated silicon subwavelength grating (SWG) waveguide and bowtie antenna is designed and experimentally demonstrated. The microwave sensor receives wireless microwave signals via the bowtie antenna. The electrical field between the extension bars of the bowtie antenna modulates the light guided in the SWG based Mach–Zehnder interferometer (MZI). Thus, microwave signals can be detected by measuring the intensity variation of light from the MZI output. The EO polymer infiltrated SWG does not require ion implantation and has low optical propagation loss. Furthermore, compared to slotted silicon waveguides, the EO polymer poling efficiency on SWG structure can be greatly increased due to wider poling separations and thus the increased breakdown voltage. In order to achieve strong microwave field enhancement, the impedance of the bowtie antennas is tailored. The optimized bowtie antennas operate at 15 GHz and provide >1000X field enhancement while only occupy an area of 7.6 mm X 0.3 mm. Leveraging the folded SWG waveguide, high EO coefficient polymer, and large field enhancement from bowtie antenna, an ultra-sensitive and compact microwave photonic sensor has been demonstrated.