Application of two-output port fiber coupler as gasoline level sensor

Detection of gasoline level can be done in a safe and simple way using two output port multimode fiber coupler with a structure of 2 × 2 as a sensor. Two output ports (sensing port) are connected with two reflector displacement device (RDD) and functioned as two probes. These probes are placed on the wall of gasoline tank in a storied and work interchangeably or together depending on setting of these probes. Detection mechanism of the system is based on changes in intensity of reflected light from the reflector RDD that shifts due to changes in level of gasoline (hydrostatic pressure principle). Changes in intensity of light coming into the sensing port are then forwarded to the optical detector. Experiments performed by varying the location of the second probe as 45 cm, 50 cm, and 55 cm above the first probe to detect the level of gasoline in the process of filling and emptying the tank. Experimental results show the process of filling and emptying the tank have small differences of 6% with the dynamic range, the linear region, and resolution are 100 cm, 70 cm, and 0.4 cm respectively. Sensor sensitivity in filling and emptying process of the tank are 2.7 mV/cm and 2.8 mV/cm respectively. These results were the best performance of the sensor, which occurs when the level of the second probe was 55 cm above the first probe.