Theoretical Study of Optical Fiber-based SPR Sensors Application for Colorectal Cancer Diagnosis Through Histological Analysis

An optical fiber-based surface plasmon resonance sensor for colorectal cancer diagnosis is presented here. A theoretical analysis is performed, where parameters such as length of the sensing region, full width at half maximum, figure of merit, and signal-to-noise ratio are investigated for three different biochip configurations. Regarding the coating, we analyzed silver, gold and copper thin films. A multimode plastic optical fiber has been used as an optical substrate, where the sensing region (i) is localized at the center of the optical fiber, (ii) is polished as a D-shaped format, or (iii) is localized at one of the fiber tips. Among the thin metal films, silver provides the higher sensitivity of 5,742 nm/RIU for a 40 nm-thick thin film. The simulated results show that values of 59.81 nm, 195.99 RIU
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, and 0.33 a.u. for the full witdh at half maximum, figure of merit, and signal to noise ratio, respectively, can be achieved for the conventional biochip.