The COB (Chip-on-Board) packaged optical module market is experiencing rapid expansion driven by the escalating demand for high-speed data transmission and burgeoning data center infrastructure globally. In the typical approach, pads on the die are wire-bonded to board traces, then protected with an encapsulant—often the black “glob top. ” Some builds add underfill for stress relief. COB, BOX, and TO-CAN packaging each offer unique advantages tailored to specific applications.