Modular Optic Force Sensor for a Surgical Device Using a Fabry–Perot Interferometer

The ability to sense force in surgery is in high demand in many applications such as force feedback in surgical robots and remote palpation (e.g., tumor detection in endoscopic surgery). In addition, recording and analyzing surgical data is of substantial value in terms of evidence-based medicine. However, force sensing in surgery remains challenging because of the specific requirements of surgical instruments, namely, they must be small, bio-compatible, sterilizable, and tolerant to noise. In this study, we propose a modular optic force sensor using a Fabry–Perot interferometer that can be used on surgical devices. The the proposed sensor can be implemented like a strain gauge, which is widely used in industrial applications but not compatible with surgery. The proposed sensor includes two key elements, a fiber-optic pressure sensor using a Fabry–Perot interferometer that was previously developed by one of the authors and a structure that includes a carbide pin that contacts the pressure sensor along the long axis. These two elements are fixed in a guide channel fabricated in a 3 × 2 × 0.5 mm sensor housing. The experimental results are promising, revealing a linear relationship between the output and the applied load while showing a linear temperature characteristic that suggests temperature compensation will be needed in use.