10 Gbps optical add-drop transponder, which can accommodate VSR (very short reach) to LR (long reach) subnetworks, is designed and implemented. The transponder consists of an OCA (optical transport network connection assembly), a SCA (sub-network connection assembly), and a FECA (forward error correction assembly). The transponder consists of an OCA (optical transport network connection assembly), a SCA (sub-network) connection assembly, and a FECA (forward error correction assembly).