As laser diodes (LDs) replace LEDs in the remote phosphor setup, a new class of lighting solutions emerges, giving rise to laser-excited remote phosphor (LERP) systems. While already in use in some commercial applications such as automotive lighting, these systems have not yet matured. The optical behavior of phosphors is temperature dependent, specifically the absorption coefficient, the conversion efficiency reflected in the quantum efficiency (QE) coefficient, and, to a lesser extent, the emission spectrum. For this reason, opto-thermal analysis is critical for further investigating and optimizing these systems. A steady-state opto-thermal simulation scheme that combines ray tracing in OpticStudio software with heat transfer calculations using the finite element method (F.E.M.) in ANSYS is presented and experimentally validated here. Furthermore, the temperature-dependent models established for phosphor properties are used to optimize the phosphor sample.