The QSFP-100G-ER4L-S is a 100 Gigabit Ethernet (100GbE) Quad Small Form-Factor Pluggable (QSFP28) transceiver designed for long-reach single-mode fiber (SMF) communication. “ER4L” indicates an Extended Reach 4-lane Lite variant. It typically supports distances up to 40 kilometers. This module uses wavelength-division multiplexing (Western DigitalM) to transmit four 25Gbps wavelengths over a single pair of fibers. It’s commonly used in data center interconnects (DCIs) and telecommunications networks where extended reach is required. The “S” usually signifies a standard commercial temperature range.
