CONCLUSION
In this paper, an all-optical fiber RI sensor based on multimode
interference has been proposed and experimentally demonstrated. SCS
configuration comprises of CLF section which represent the sensing area
spliced between two small pieces of SMF. A various diameters of CLF of
100 and 50 μm with three different tune lengths 20, 25 and 30 mm have
been employed as a sensing area to substitute the traditional MMF. The
effect of CLF diameter variation on the sensor performance has been
examined. Chemical etching process was used to tune the CLF diameter
from 100 to 50 μm. The experimental results of the SCS configuration
encompassed of the etched CLF at 50 μm diameter with a CLF length of 25
mm exhibited the greatest sensitivity of about 1012 nm/RIU. The SCS
structure has attractive benefits such as low cost, high measurement
sensitivity, simple structure, and fast response.