Palm oil is one of common consumed raw food and found adulterated with another materials such as lard. Palm oil adulteration can cause some problems in norms and health. Some methods have been developed in detect lard mixing in foods such as spectroscopy based methods, including infrared spectroscopy and some methods which is complex, expensive, and need of experts. In other side, plastic optical fiber with u-shaped configuration has been developed as biosensors. Through utilization of evanescent field and effect of the change in refractive index to the transmitted power, it has been design a sensor based on plastic optical fiber to detect lard adulteration in palm oil. Experiments show that the most optimal sensor design based on plastic optical fiber with u-shaped configuration is sensor with Infrared LED as light source, 50 mm curvature radius of bend, dan 2 cm length of peeled cladding. From the experiments, sensitivity of the sensor is 0.15630352 μW / % lard concentration.
In this paper, a load effect on a singlemode-multimode-singlemode (SMS) fiber structure embedded in a high-density
polyethylene (HDPE) was investigated numerically and experimentally. It was modelled that the applied load induces a
longitudinal strain on the HDPE and accordingly affects the SMS fiber structure’s parameters. It was calculated the
output power of the SMS fiber structure using a graded index multimode fiber (MMF) due to the applied strain from 0 to
4000 N. The experimental result shows that for the MMF length of 105 mm, the output power has monotonically
increasing for an applied load range from 1700 to 4000 N with a sensitivity of 1.18 x 10-3 dBm/N. This configuration of
SMS fiber structure embedded in the HDPE is potential for a load sensor.