This study presents an approach that achieves single transverse mode lasing in 760 nm vertical cavity surface emitting lasers by depositing a high-index SiO₂/Ti₃O₅ dielectric film on the p-type distributed Bragg reflector (P-DBR) to form a composite cavity with the N-DBR and P-DBR. Simulations show enhanced optical path and field confinement, which reduce mode competition. At 20 °C, the device achieves a 0.7 mA threshold, 2 mW output at 5.5 mA, and 20.09 MHz linewidth at 4 mA. At 80 °C, the side-mode suppression ratio reaches 43.3 dB at 1.5 mA and remains >35 dB, indicating good thermal stability.