The traditional distributed Bragg reflector (DBR), which is constructed with multiperiod films with alternating low and high refractive indices, has a low full width at half maximum (FWHM), but both the ripple number and ripple intensity increase outside the reflectance band. In this study, Ta2O5 and SiO2 films with refractive indices of 2.10 and 1.45 were used as the low- and high-refractive-index films, respectively, to design a traditional red-light DBR with a central wavelength of 7000 nm. First, we used COMSOL Multiphysics as a tool to simulate the designed DBR. Although the designed reflector had a low FWHM value, it had high ripple intensities outside the reflectance band. Therefore, we designed a modified DBR with a structure of 15 layers and with different thicknesses of the upper and bottom layers. The modified DBR had a smaller FWHM, a higher reflectance, and smaller ripple intensities outside the reflectance band. Although the ripple intensities were lower than those of the traditional DBR, they were still higher than 20%. Next, we also used the optimization function of COMSOL Multiphysics to suppress the ripple intensities, and we showed that the ripple intensities were indeed suppressed.