Conventional chromatic methodology for optical fibre sensing utilises a broadband spectral source and three photodetectors with nonorthogonal wavelength responsivities. Because of the reciprocal nature of chromatic processing the chromatic functionality of the light source and the photodetectors can be interchanged where by a number of photodetectors can be replaced by a number of light sources and a broadband light source can be substituted with a broadband photodetector. This approach allows more versatility in the design and usages of chromatic based optical fibre sensor systems and moreover ease practical implementation particularly for realising higher order stimulus system (ie. N > 3 where N is the number of chromatic processors). In this thesis the principle has been demonstrated practically via three applications. These include 1.) A defective battery identifying system, 2.) Thermochromic liquid crystals based optical temperature sensor system, and 3.) Blood and oxygen level analysis of the skin blood spectrum.