A simple technique for detecting the broad range of organic/inorganic materials

Abstract

A simple single-fiber (SF) Mach-Zehnder interferometer (MZI) based technique for identifying any known/unknown organic/inorganic substance, has been proposed. The suggested process involves the quantification of the contribution of tapered and un-tapered sections of SF-MZI in its optical interference length by modifying the existing expression of its free spectral range (FSR). Each chemical/biological material/entity, possesses specific properties and the proposed method aims to enumerate the characteristic features of the material with a particular identification number. A dual tapered fiber based SF-MZI is employed for sensing four types of chemical compounds by submerging the tapered fibers with varied concentrations of the compounds. The effect of systematic alteration in refractive index (RI) of surrounding of the tapered fibers results in blue shift in the spectrum recorded on optical spectrum analyzer (OSA). The experimental spectral shift is correlated, within the unveiled theoretical framework, with variation in RI for determining the sensitivity, optical interference length of tapered and un-tapered region, and the unique identification parameter for each compound. The presented framework shall be useful in developing an integrated method for sensing various chemical and biological entities.