In this study, we investigate the photoelectric detection phase characteristics of FOHs based on the 3 × 3 coupler demodulation technique. Detection in Narrow Locations The small sensing section and flexible Fiber Unit cable enable a Fiber Sensor to. Fiber optic sensors are devices that transform the state of an object being measured into a detectable optical signal. Our model. Photoelectric sensors and fiber optic sensors are very similar in a lot of ways, but which one is superior in function and durability, and under what conditions might one be preferred? Detecting the presence of materials or parts is an essential process of automation. It's a device that converts light rays into electronic signals.