100G optical module normal optical receiving power
100G optical modules have defined transmit and receive power ranges depending on the standard, fiber type, and distance, ensuring reliable 100Gbps data transmission.Overview of 100G Optical Modules100G optical modules, such as QSFP28, CFP4, and CFP2, support 100GbE transmission using multiple lanes, typically 4 lanes of 25Gbps each, or 2 lanes of 50Gbps in bidirectional designs . Modules are categorized by distance and fiber type:Short-reach (SR4, SR10, SWDM4, BiDi SR): Multimode fiber, distances up to 100–150 meters .Medium-reach (CWDM4, PSM4, FR): Single-mode fiber, distances 500 meters to 2 km .Long-reach (LR4, ER4, ZR): Single-mode fiber, distances 10 km and beyond .Transmit Power StandardsTransmit power is the optical power emitted by the module's laser. Typical ranges vary by standard:100GBASE-SR4 (multimode): Transmit power per lane ~ -4.3 dBm to 2.4 dBm .100GBASE-LR4 (single-mode, 10 km): Transmit power per lane ~ -8.4 dBm to 2.4 dBm .100GBASE-FR4 (single-mode, 2 km): Transmit power per lane ~ -8.4 dBm to 2.4 dBm .100G CWDM4 (single-mode, 2 km): Transmit power per lane ~ -7.5 dBm to 2.5 dBm . Modules using PAM4 modulation may have slightly higher transmit power requirements due to signal encoding.Receive Power StandardsReceive power is the minimum and maximum optical power the module can reliably detect:100GBASE-SR4: Receive sensitivity per lane ~ -9.5 dBm to 2.4 dBm .100GBASE-LR4: Receive sensitivity per lane ~ -11.1 dBm to 2.4 dBm .100GBASE-FR4: Receive sensitivity per lane ~ -11.1 dBm to 2.4 dBm .100G CWDM4: Receive sensitivity per lane ~ -11.1 dBm to 2.5 dBm . The power budget (difference between transmit and receive power) ensures reliable operation over the specified fiber distance, accounting for fiber loss, connector loss, and dispersion.Key ConsiderationsFiber Type: Multimode fibers (OM3/OM4/OM5) have higher attenuation; single-mode fibers support longer distances.Lane Architecture: Modules with multiple lanes (SR4, LR4) split the 100G signal into parallel channels, affecting per-lane power requirements.FEC (Forward Error Correction): Required for FR4 and LR4 modules to maintain signal integrity over longer distances .Connector Type: LC duplex, MPO/MTP, or vendor-specific connectors influence insertion loss and power budget.SummarySelecting a 100G optical module requires matching transmit and receive power ranges to the fiber type, distance, and application scenario. Short-reach multimode modules have higher transmit power and shorter distances, while long-reach single-mode modules require lower transmit power but higher sensitivity to maintain signal integrity over kilometers. Compliance with IEEE 802.3 and MSA standards ensures interoperability and reliable 100Gbps performance .