Hollow-Core Coaxial Fiber Sensor for Biophotonic Detection

In this paper, a photonic biosensor based on a hollow-core coaxial fiber is presented and discussed. The sensor is aimed to detect the presence of specific biomarkers in a complex human compound, e.g., serum, urine, saliva, cell lysate. The target detection occurs through a biological binding that alters the mode confinement of the Bragg structure. A generic (suboptimal) structure is designed by using the transfer matrix method. The sensor performances are shown in terms of confinement losses. For spherical protein of 5 nm, the confinement loss is increased of 1.213 dB/m. Furthermore, a parametric analysis is performed, which drives toward the possible optimization of the fiber. From a practical point of view, the joint application of selective molecular functionalization of fiber interfaces, and multilayer fiber “rolling” technique are believed to enable for the realization of the sensor.