"A semi-automatic and reconfigurable mechatronic stage was designed and implemented to precisely control the fiber cleaving in the process of manufacturing Fabry-Perot (FP) microcavities. FP interferometers with a cavity length as small as 5 μm, were achieved with this system. The theoretical reflectance of the fiber cavities was studied by the interference phenomenon simulation. Then, a comparison technique between the experimental and simulated spectra was performed to calculate the length of this FP cavities fabricated. The FP cavities presented can be used to develop sensor in many fields; ranging from the industrial to sensing applications."