Optical Sensor Chips Monitored via Extrinsic Optical Fiber Schemes

The peculiar features of optical fibers (OFs) allowed their use in the monitoring of optical sensor probes through extrinsic schemes. In this type of platform, OFs serve solely as waveguides, directing input light to the sensing region and collecting it. This feature enables remote sensing, allowing the signal to be collected at a considerable distance from the sensing area. OFs have been extensively used to obtain highly sensitive extrinsic schemes by combining optical transducers with different kinds of receptors (e.g. aptamers, antibodies, molecularly imprinted polymers, etc.) to detect specific analytes in the required range of detection. Additionally, physical quantities measurements have been also performed through extrinsic schemes. This review summarizes the OF-based extrinsic schemes adopted in different application fields, by comparing the production processes, the performances, the advantages and disadvantages of each configuration.