We introduce a simple and effective heat sink structure for thin-film vertical cavity surface emitting lasers (VCSELs) in fully embedded board level guided-wave interconnects. A 50% quantum efficiency increase is experimentally confirmed for the 10-μm thin-film VCSELs. The thermal resistance of a 1 × 12 embedded thin-film VCSEL array in printed circuit board (PCB) is further analyzed. The experimental results show an excellent match with the simulated results. The 10-μm-thick VCSEL had the lowest thermal resistance and the highest differential efficiency compared to 250-, 200-, 150-, and 100-μm-thick VCSELs. A substrate removed VCSEL can be used in fully embedded board level optical interconnects without special cooling techniques.