EL RÉGIMEN PARXIAL DE LA ÓPTICA ONDULATORIA ESCALAR TIENE LA MISMA ESTRUCTURA QUE LA MECÁNICA CUÁNTICA NO RELATIVISTA, DONDE LA LONGITUD DE ONDA JUEGA EL PAPEL DE LA CONSTANTE DE PLANCK. LA FUNCIÓN DE WIGNER ES UNA HERRAMIENTA CENTRAL PARA EXPLORAR EL ESPACIO FASE DE UN SUSTEMA; ADEMÁS, EN ÓPTICA, SE PUEDE PRODUCIR CON MEDIOS EXCLUSIVAMENTE ÓPTICOS. EN ESTA PRIMERA PARTE, PRESENTAMOS UN FORMALISMO MATRICIAL PARA EL ESTUDIO DE LOS SISTEMAS ÓPTICOS PARXIALES Y LO APLICAMOS EN LA DESCRIPCIÓN DE UN ARREGLO, QUE COMO VEREMOS EN LA SEGUNDA PARTE, PRODUCE LA FUNCIÓN DE WIGNER.AbstractTHE PARAXIAL REGIME OF SCALAR WAVE OPTICS HAS THE SAME STRUCTURE AS NON-RELATIVISTIC QUANTUM MECHANICS, WITH WAVELENGTH TAKING THE PLACE OF THE PLANCK CONSTANT. THE WIGNER FUNCTION IS A CENTRAL TOOL TO EXPLORE THE PHASE SPACE OF A SYSTEM; IN OPTICS, MOREOVER, IT CAN BE PRODUCED BY PURELY OPTICAL MEANS. IN THIS FIRST PART, WE PRESENT A MATRIX-BASED FORMALISM FOR THE STUDY OF PARAXIAL OPTICAL SYSTEMS, AND APPLY IT TO THE DESCRIPTION OF A SETUP THAT, AS WILL BE SEEN IN THE SECOND PART, PRODUCES THE WIGNER FUNCTION.THE PARAXIAL REGIME OF SCALAR WAVE OPTICS HAS THE SAME STRUCTURE AS NON-RELATIVISTIC QUANTUM MECHANICS, WITH WAVELENGTH TAKING THE PLACE OF THE PLANCK CONSTANT. THE WIGNER FUNCTION IS A CENTRAL TOOL TO EXPLORE THE PHASE SPACE OF A SYSTEM; IN OPTICS, MOREOVER, IT CAN BE PRODUCED BY PURELY OPTICAL MEANS. IN THIS FIRST PART, WE PRESENT A MATRIX-BASED FORMALISM FOR THE STUDY OF PARAXIAL OPTICAL SYSTEMS, AND APPLY IT TO THE DESCRIPTION OF A SETUP THAT, AS WILL BE SEEN IN THE SECOND PART, PRODUCES THE WIGNER FUNCTION.