We demonstrate a novel architecture of mounting parallel-optical modules (POMs) onto an optical printed circuit board (PCB) through Sn-Ag-Cu-solder reflow process where precisely positioned stud-pins on optical PCB and guide holes formed on POMs were mated to maintain good optical coupling. We confirmed that fabricated 14-Gb/s × 12-channel POMs achieved a good transmission performance on a test environment using evaluation boards. Then, the POM was mounted onto the optical PCB through Sn-Ag-Cu-solder reflow process actually. We report coupling loss characteristics and signal qualities at 14-Gb/s PRBS 231-1 for the optical link using POM-mounted optical PCBs.