An optical fiber (100) utilized as a sensor for measuring a parameter of interest 122 such as temperature, strain, photonic energy intensity, electric field intensity and magnetic field intensity is provided. A first optical cladding layer (104) is disposed on an optically transmissive core (102) that includes one or more optical gratings (114-1). The optical grating(s) (114-1) modifies a propagation path of selected wavelengths of light propagating through the core (102). The optical grating(s) (114-1) also varies the index of refraction of the first optical cladding layer (104). The selected wavelengths of light are determined in part by the index of refraction of the core material 105 as dependent upon a parameter of interest 122 applied to the core material 105 and as varied by the optical grating(s) (114-1). One or more detectors (410, 430, 450, 455) are used for determining the properties of the reflected and/or transmitted light. Knowing the properties of the reflected and/or transmitted light, a parameter of interest 122 can be determined.