Beam modulation as an intensity force sensor based on plastic optical fiber

The use of plastic optical fibers as sensors represents advantages due to the malleability of the material and the number of modulations it allows, in addition, it's a flexibility and low-cost material. Currently, optical couplers have also been developed in plastic fiber optics, due to their main use in telecommunications, and prices are increasingly affordable. In addition, the use of technologies in optics and photonics are more accepted in areas such as medicine, industry, beauty, sensors, and more. (1) In this work, a force sensor is achieved, based on beam modulation, made of a 2x2 (50:50) coupler of 1mm diameter Plastic Optical Fiber (POF), with a 10 cm POF joined to the output to generate a loop. This section was polished in D, V and cylindrical shapes, at 30% and 50% polished depth, using a visible spectrum, in 632.8 nm of an He-Ne laser source. The spectral response is obtained in a force range of 0-500 N which is gradually applied to the fiber polished section. A linear sensitivity of force-beam modulation is obtained.