Towards a fully packaged high-performance RF sensor featuring slotted photonic crystal waveguides

A low loss and high sensitivity X-band RF sensor based on electro-optic (EO) polymer filled silicon slot photonic crystal waveguides (PCW) and bowtie antenna is proposed. By taking advantage of the slow light enhancementt in the PCW(>20X), large EO coefficient of the EO polymer(r33>200pm/V), as well as significant electric field enhancement of bowtie antenna on silicon dioxide substrate(>10000X), we can realize a large in-device EO coefficient over 1000pm/V so as to realize a high performance RF wave sensor. In addition, on-chip Mach-Zender interferometer (MZI) layout working under push-pull configuration is adopted to further increase the sensitivity of the sensor. Furthermore, inverse taper couplers and slotted photonic crystal waveguides are carefully designed and discussed in this paper to reduce the insertion loss of the device so as to increase the device signal-to-noise ratio. The minimum detectable electromagnetic power density is pushed down to 2.05 mW/m2, corresponding to a minimum sensing electric field of 0.61 V/m. This photonic RF sensor has several important advantages over conventional electronics RF sensors based on electrical scheme including high data throughput, compact in size, and great immunity to electromagnetic interference (EMI).