Silicon microring modulator array controlled all optically

Silicon photonics involving microring modulators is a promising platform for radio-over-fiber (RoF) applications. Here, we assume that microring modulators are driven by integrated RF antennas and their resonance are tuned by optical heaters pumped by control light. This configuration eliminates the need for electrical connections and simplifies the operation of local RoF devices located far from base stations. In this paper, we demonstrate optical heater control of four microring modulators. By designing optical heaters and appropriately setting the control-light power, the modulators are sequentially selected, and the input signal light is modulated by RF signals applied to the selected modulator. This concept can be applied to a two-dimensional modulator array using wavelength-division multiplexing.