FWLF-1631-41 is a DWDM SFP transceiver designed for metropolitan access and core networks requiring dense wavelength-division multiplexing capabilities. The module operates at a center wavelength of 1544.53 nm (194.1 THz) with support for data rates up to 2.7 Gb/s in bi-directional configuration, featuring a temperature-stabilized DFB laser transmitter and extended link budget with APD receiver technology. It provides 120 km reach performance with low dispersion characteristics and wavelength control within ±0.1 nm over life and temperature, compliant with SONET OC-48 LR-2 and Gigabit Ethernet standards. The transceiver operates over an extended case temperature range of -5°C to 70°C and is housed in a hot-pluggable SFP footprint compatible with the DWDM SFP Multi-Sourcing Agreement. Applications include amplified DWDM and SONET networks, bandwidth aggregation, and ring topologies with fixed and reconfigurable optical add-drop multiplexers (OADMs).