Fabrication of a micro-cantilever sensor on a single mode fibre by picoseconds laser

Micro-cantilevers are one of the most popular Micro-Electronics-Mechanical-Sensor (MEMS). They've demonstrated in a number of application areas such as chemical and bio-sensing. However, these devices usually need the alignment of the cantilever with the read-out system, which can be challenging. Furthermore, it involves a bulky free-space optical detection system. In this paper, we propose techniques to design and fabricate micro-cantilevers onto the end of standard single mode fibres using a picoseconds (ps) laser machining technique. In this way the cantilever can be aligned with the core of the fibre therefore offering stable and accurate means of optically addressing the cantilever. Low-cost optical sources and fibre coupled spectrometers are employed to interrogate the final cavity with a resolution around 15nm. Experiment show this optical fibre cantilever can be used as a displacement sensor with a dynamic range up to 7 mu m. Proof-of-concept experiments demonstrate that the cantilever could also be used as a temperature sensor in the range of 24-320 degrees C with a temperature sensitivity of 0.5 degrees C.