Abstract. In this paper, we consider the real modified Korteweg-de Vries (mKdV) equation and construct a special kind of breather solution, which can be obtained by taking the limit λ j → λ 1 of the Lax pair eigenvalues used in the n-fold Darboux transformation that generates the order-n periodic solution from a constant seed solution. Further, this special kind of breather solution of order n can be used to generate the order-n rational solution by taking the limit λ 1 → λ 0 , where λ 0 is a special eigenvalue associated to the eigenfunction φ of the Lax pair of the mKdV equation. This eigenvalue λ 0 , for which φ(λ 0 ) = 0, corresponds to the limit of infinite period of the periodic solution. Our analytical and numerical results show the effective mechanism of generation of higher-order rational solutions of the mKdV equation from the double eigenvalue degeneration process of multi-periodic solutions. During the last 50 years, the concept of solitons has been widely studied in different branches of Nonlinear Science and experimentally observed in diverse areas like hydrodynamics, fiber optics, quantum gases, Bose-Einstein condensation etc. Several effective mathematical tools and softwares have been developed to construct soliton solutions of a plethora of nonlinear partial differential equations. During these interesting developments, in addition to soliton solutions, several other explicit solutions like dromions, positons, breathers, similaritons, rogue waves etc. have also been reported for many nonlinear partial differential equations. In particular, the generation of higher-order rogue waves from breather-type periodic solutions has attracted a lot of attention in recent years. To the best of our knowledge, the concept of breather-positon is not well investigated. In this paper, we report breather-positon solutions to the real modified Korteweg-de Vries (mKdV) equation and construct these exact solutions from the n-fold Darboux transformation that generates the order-n periodic solution from a constant seed solution. We also generate the order-n rational solutions by taking a suitable limit in terms of the eigenvalue of the associated Lax pair of the mKdV equation. To visualize our above ideas, we consider an optical fiber setting and demonstrate that the second limit of double eigenvalue degeneration process might be realized approximately by injecting an initial ideal pulse, which is created by a comb system and a programmable optical filter according to the profile of the analytical form of the breather-positon at a certain spatial position. Through this work, we propose a protocol to observe the higher-order rational solutions in Kerr-type nonlinear optical media, namely, to measure the wave patterns at the central region of the higher order breather-positon generated by ideal initial pulses with suitable limiting condition.