The contactless real-time temperature sensing technique with high temporal and spatial resolution is in high demand for the countless applications. Here, the Yb ³⁺/Er ³⁺⁻codoped GeO ₂–PbO–PbF ₂ glass ceramics synthesized via the melt-quenching technique has been presented as an optical thermometer. The thermal sensing was designed based on the temperature dependent fluorescence intensity ratios of thermally ( ²H _11/2 and ⁴S _3/2) and non-thermally ( ²H _11/2 and ⁴F _9/2) coupled Er ³⁺ levels. The ratiometric techniques provide the thermal sensing within the temperature range of 300–466 K. The absolute and relative thermal sensitivities as well as the temperature resolution were calculated and compared with other Yb ³⁺/Er ³⁺-doped materials. The temperature of the microelectronic component on the printed circuit board was defined using the optical thermometry as a proof of concept revealing Yb ³⁺/Er ³⁺⁻codoped GeO ₂–PbO–PbF ₂ phosphor to be a promising candidate for precise non-contact thermal sensor.