Light guides, fiber-optic chemical sensors

A variety of transducer configurations that has been employed in photometric sensor devices fall into two sensor types extrinsic sensors and intrinsic sensors. While in the former sensor type the optical fiber merely acts as a light guide, conveying the optical information between the optical source and the chemical transducer and between the chemical transducer and the detector, in the latter sensor type the optical fiber, probably in some modified form, would become a part of the transducer. 

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