In this work, we investigate a new type of fluoride glasses modified by Al(PO3)3 with various Tm3+/Ho3+ doping concentrations. The introduced PO3 plays an effective role in improving the glass-forming ability and thermal stability. Besides, 1.47, 1.8, and 2.0 μm emissions originating from Tm3+ and Ho3+, respectively, are observed. The spectroscopic properties and energy transfer mechanisms between Tm3+ and Ho3+ are analyzed as well. It is noted that the higher predicted spontaneous transition probability (118.74s 1) along with the larger product of measured decay lifetime and the emission cross section (σemi×τ) give evidence of intense 2.0 μm fluorescence.