Low-cost optical fiber temperature-sensing system employing optical transceivers for Ethernet and long-period fiber grating.

Optical fiber sensors have numerous advantages over electrical sensors. However, in some cases, sensing systems based on optical fiber sensors are inferior to electrical sensors in terms of cost because expensive instruments are required. Therefore, cost-effective options must be developed. Here, inexpensive optical transceivers (OTRs) for Ethernet were used instead of a broadband light source and optical spectrum analyzer, and a CO laser-induced long-period fiber grating (LPFG) was used as a temperature sensor. The sensing system was implemented introducing OTRs and LPFG in an experimental internet protocol (IP) over Ethernet. The results showed that a low-cost sensing system can estimate the ambient temperature of the LPFG based on the no-reply rate for the internet control message protocol echo request. Regarding the sensing performance, the measurable range was ∼100°C with ±4.5°C errors.