Resumen Los fen omenos f sicos de nuestro entorno han llevado al ser humano a crear desarrollos tecnol ogicos basados en investigaciones cient cas para medir las variables f sicas. En mec anica de materiales, el an alisis, determinaci on de esfuerzos y deformaciones, es de gran importancia para la comprensi on del comportamiento de la resistencia un material o de una estructura al aplicarle una fuerza externa. Este trabajo de investigaci on se enfoca al estudio y comprobaci on de la t ecnica de bras opticas con estructura Singlemode- Multimode- Singlemode (SMS); se demuestra que es adecuada como elemento sensitivo aplicable en la medici on de deformaci on longitudinal en un elemento mec anico sometido carga axial (tensi on-compresi on) y el an alisis experimental del estado esfuerzos uniaxial. Adem as, se realiza una comparaci on con una t ecnica ampliamente desarrollada y madura como lo es la extensometr a cl asica. Se instrumentaron ambas t ecnicas, una galga extensom etrica y una bra SMS, en la misma super cie realizando ensayos de exi on de vigas en voladizo aplicando una carga controlada.Abstract The physical phenomena in our environment have led humans to create technological developments based on scienti c research to measure physical variables. In materials mechanics, the analysis, determination of stresses and deformations, is of great importance for understanding the behavior of the resistance of a material or a structure when applying an external force. This research work is focused on the study and validation of the technique of optical bers with a Singlemode-Multimode-Singlemode (SMS) structure; It is shown that it is suitable as a sensitive element applicable in the measurement of longitudinal deformation in a mechanical element subjected to axial load (tension-compression) and the experimental analysis of the uniaxial stress state.In addition, a comparison of a widely developed technique as is classical extensometry are presented. Both techniques, a strain gage and an SMS ber, on the same surface making cantilever beam bending tests applying a controlled load were instrumented. The main contribution is the spatial adaptability for lossless electrical measurements. The feasibility of using SMS ber is demonstrated in a linear iii range of up to 800 " , this characteristic makes it possible to highlight that this is an alternative method for the measurement and experimental analysis of the state of deformations.