This　study　investigates　the　thermal　design　of　2-D　vertical-cavity　surface-emitting　laser　(VCSEL)　arrays　for　optical　output　power　improvement.　Considering　the　temperature　dependencies　of　bias　current,　internal　quantum　efficiency,　internal　optical　loss,　and　thermal　resistance　of　each　array　cell,　a　compact　electro-opto-thermal　model　of　2-D　VCSEL　arrays　with　linear　power　dissipation　and　quadratic　power　dissipation　in　each　array　cell　is　established　to　study　the　effects　of　array　cell　spacing　and　layout　on　the　device　performance.　At　the　same　time,　the　power　dissipation　mechanisms　contributing　to　thermal　rollover　are　also　studied.　It　is　found　that　the　array　cell　spacing　has　a　strong　influence　on　the　linear　power　dissipation,　and　the　layout　(such　as　hexagonal　design)　influences　quadratic　power　dissipation　obviously.　With　the　careful　design　of　array　cell　spacing　and　layout,　both　the　temperature　profile　and　the　thermal　resistance　matrix　of　VCSEL　arrays　are　improved,　which　is　helpful　to　delay　the　onset　of　thermal　rollover　and　hence　enhance　the　optical　output　power.　The　simulation　results　are　consistent　with　experimental　results.