Single-mode optical modules are used for long-range transmission, typically 10 km, 40 km, and 80 km. Unlike general optical modules with two ports (Tx and Rx), BiDi optical modules have only one optical port and use wavelength division multiplexing (WDM) technology to transmit and receive optical signals of different center wavelengths over the same fiber. A frequent source of confusion comes from real-world deployment experiences shared across engineering communities. This article explores the ETU-LINK 100G BIDI (Bidirectional) 80KM Optical Module, focusing on its product overview. This is where 100G QSFP28 80km BiDi optical modules start to make sense. These modules are designed to transmit 100G Ethernet signals across single-mode fiber over distances up to roughly 80 kilometers.
