Chip-scale wavelength-division multiplexed integrated sensor arrays

We demonstrate a wavelength-division multiplexing (WDM) technique for interrogating multiple sensors on a single chip. While wavelength- and frequency-division multiplexing (FDM) has previously been demonstrated in micro-electro mechanical (MEMS) sensors, numerous off-chip components were required thereby increasing the system size and limiting the number of sensors. In contrast, our approach enables all components to be developed on-chip. The high Q-factor afforded by optical microcavities enables a large number of sensor elements to be interrogated using WDM. First, we demonstrate wavelength-enabled addressing of individual sensors. Next, we show how two sensors can be individually interrogated in a sensor network. Finally, we illustrate how such "sensor-networks on a chip" are fabricated. The ability to develop large-scale arrays, where each sensor has been functionalized to respond to a different analyte, enables increased selectivity for MEMS resonant chemical sensors.