Micro-Machined Optical Fiber Side-Cantilevers for Acceleration Measurement

We propose an accelerometer based on a micro-cantilever fabricated onto the side of a single mode optical fiber using a combination of ps-laser machining and focused ion beam (FIB) processing. FIB machining is also used to fabricate a 45° mirror onto the end of the fiber that is accurately aligned with optical fiber core. This provides a reliable means to optically address components attached to the side of the fiber, such as the cantilever. Using interferometry to accurately monitor the deflection of the side cantilever results in a device that is capable of measuring two-axis acceleration. Acceleration up to 6 g is measured with a resolution of ~0.01 g and a frequency range from dc to 500 Hz has been demonstrated. The cross-axis sensitivity is below -32 dB.