Gold film effect on temperature compensation of a POF sensor with different structures

In this paper, temperature compensation of plastic optical fiber (POF) is studied and gold absorbability is utilized. Gold film is modified on the surface of POF by magnetron sputtering. The temperature output characteristics of different structures such as ordinary (POF-N), side-polished (POF-SP), U-shaped (POF-U), and narrow groove structure (POF-NGS) are tested, and the effects of gold film thickness, polishing area, and sputtering sequence on the temperature output characteristics are also investigated. The power change of the sensor at different temperatures is recorded. The experimental results show that when the temperature is between 25°C and 50°C and the sputtering gold film thickness is 50 nm, the temperature stabilities of POF-N, POF-U, POF-SP, and POF-NGS are 1.02 µW/°C, 0.77 µW/°C, 0.18 µW/°C, and 0.35 µW/°C, respectively. The compensation effect is enhanced as the gold film thickness increases. When the thickness is 100 nm, the temperature stability of POF-NGS is 0.06 µW/°C. The proposed temperature compensation method is competitive and straightforward.