Demonstration of microcantilever array with simultaneous readout using an in-plane photonic transduction method

We demonstrate a microcantilever array with an in-plane photonic transduction method for simultaneous readout of each microcantilever. The array is fabricated on a silicon-on-insulator substrate. Rib waveguides in conjunction with a compact waveguide splitter network comprised of trench-based splitters and trench-based bends route light from a single optical input to each microcantilever on the chip. Light propagates down a rib waveguide integrated into the microcantilever and, at the free end of the microcantilever, crosses a small gap. Light is captured in static asymmetric multimode waveguides that terminate in Y-branches, the outputs of which are imaged onto an InGaAs line scan camera. A differential signal for each microcantilever is simultaneously formed from the two outputs of the corresponding Y-branch. We demonstrate that reasonable signal uniformity is obtained with a scaled differential signal for seven out of nine surviving microcantilevers in an array.