Silicon Photonics Based On-Chip Cantilever Vibration Measurement

In this paper, we demonstrate a compact Silicon photonics based vibrometer using an on-chip photonic grating-based sensor. The grating sensor works on the principle of interference where the motion of the cantilever is captured at the output as an intensity variation. The advantage of the grating sensor over conventional Laser Doppler vibrometer is increased tolerance to alignment errors as both the grating and the cantilever can be integrated on a single chip. The grating parameters are optimized using 2D-FDTD to achieve a maximum sensitivity to the displacement of a cantilever. Experimentally, we demonstrate dynamic measurements of a cantilever resonant mode.