Opto-mechanical lab-on-fiber accelerometers

In this paper, we investigated the realization of Lab on fiber accelerometers based on micro-opto-mechanical cavities on the optical fiber tip. Two alternative approaches have been pursued. In the former one, the opto-mechanical cavity includes a simple cantilever suspended on the optical fiber end facet. In the latter, the opto-mechanical structure consists of a membrane sustained by four cantilevers. The mechanical response of the sensors has been predicted by numerical simulations based on the finite element method. Cantilever based accelerometers have been realized by using a ferrule top approach, whilst membrane based accelerometers have been realized through a photolithographic process followed by a transferring step for the final integration on the optical fiber tip. Different accelerometers have been fabricated with different geometrical features and characterized by using a shaking table. Either cantilever and membrane based Lab on fiber accelerometers exhibited a sensitivity of about 0.1nm/(m/s2) on a 3dB-bandwidth of 5kHz with a resolution down to 100µg/(Hz)1/2. Overall, the performance comparison with the actual state of the art confirms the potentiality and the versatility underlying the integration of micro-opto-mechanical (MOM) structures with the optical fibers towards a novel class of opto-mechanical lab on fiber accelerometers.