In line Fabry-Perot cavities manufactured by electric arc fusion of NIR-laser microdrilled optical fiber flat tips

The manufacturing of inline Fabry-Perot cavities in standard single mode telecommunication optical fiber is presented. The procedure consists in splicing two optical fiber pigtails, one of them with a micro-drilled hole in its tip, creating an air bubble inside the structure. The initial hole is obtained using near infrared radiation from a Q-switch Nd:YAG laser to open 5-10 micrometers deep cavities by laser ablation and plasma formation processes, and a standard splicing machine is used to fuse the two fibers. The length of the obtained cavities lies around 80-110 micrometers. Preliminary tests as a strain sensor are presented.