Manipulating Microbending Losses in Single Mode Optical Fiber for Pressure Sensing

This paper reports the effect of microbending losses in single mode optical fiber for pressure sensing system application. Several types of periodical corrugated plates were fabricated, namely cylindrical-structured surface (Plate A) and rectangular-structured surface (Plate B) with thicknesses of corrugated parts were varied at 0.1 cm, 0.2 cm and 0.3 cm. Laser sources with excitation wavelengths of 1= 1310 nm and 2= 1550 nm were launched at the first end of the fiber. The values of losses were recorded by using an optical power meter. It was clearly seen that the microbending losses were polynomially increased with the increment of applied pressure and the thicknesses of corrugated parts of Plate A and Plate B. The maximum microbending losses of 1.5185 dBm/kPa was resulted as SMF was coupled with corrugated plates B with thicknesses of 0.3cm by using excitation wavelength of 1550nm. These values reduced to 0.7628 dBm/kPa and 0.4014 dBm/kPa as the thicknesses were decreased to 0.2cm and 0.1cm respectively. In comparison with a plain plate which acted as a reference indicator, the maximum percentage of microbending losses was obtained as 74.29 % for Plate A and 95.02 % for Plate B. In conclusions, we successfully proved the ability of SMF as a pressure sensor by manipulating the microbending losses experienced by the fiber. The employment of 1550nm of laser wavelength results better sensitivity sensor where the system able to detect large losses as the pressure applied on the corrugated surfaces.