Fiber-Optic Temperature and Pressure Sensors Applied to Radiofrequency Thermal Ablation in Liver Phantom: Methodology and Experimental Measurements

Figure 7

Setup for interrogation and decoding of the LCFBG. Interrogation is based on a white-light scheme, with a 1550 nm spectrometer for detection. The simplified decoding algorithm, as in [17], is initialized by dividing the measured LCFBG spectrum by the reference spectrum, acquired in reference condition (uniform temperature). The obtained spectral function is an almost flat curve, which depends on the whole temperature pattern, while the fluctuations at the two sides (the uppermost red and blue parts of the LCFBG spectrum) identify the temperature values at the two sides of the grating, that is, the “left” and “right” temperatures. The inner part of the spectrum is integrated and normalized for a calibration function acquired in reference condition, to estimate the thermal slope. Finally, each contribution is combined to obtain the temperature distribution through the whole LCFBG active length.