High-brightness laser lighting faces grave challenges in the development of laser-driven color converters that simultaneously possess excellent optical performance and superior heat dissipation. Herein, a reflective sandwich color converter of phosphor-in-glass film with sapphire and alumina (sapphire@PiGF@alumina, abbreviated as S@PiGF@A) is designed and prepared via a thermocompression bonding method. Owing to the high thermal conductivity and double-sided heat dissipation channels of alumina and sapphire, the S@PiGF@A color converter can withstand high laser power density and produce ultrahigh luminescence. Consequently, the optimized S@PiGF@A converter yields white light with an ultrahigh luminous flux of 6749 lm at a laser power density saturation threshold of 47.70 W/mm², which is 2.44 times that of traditional PiGF@alumina color converter (2522 lm@19.53 W/mm²). These findings provide valuable guidelines to design high-quality PiGF color converter for high-brightness laser-driven white lighting.