Cisco / QSFP-40G-SR4 / 40GBASE-SR4 4 lanes 850 nm MMF

The Cisco / QSFP-40G-SR4 / 40GBASE-SR4 4 Lanes 850 nm MMF is a genuine Cisco QSFP+ optical transceiver module engineered for high-bandwidth 40 Gigabit Ethernet deployments in data centres, high-performance computing environments, campus networks, and enterprise backbone infrastructure. The Cisco QSFP-40G-SR4 supports link lengths of 100 metres on laser-optimised OM3 and 150 metres on OM4/OM5 multimode fibre, enabling high-bandwidth 40G optical links over 12-fibre parallel cables terminated with MPO/MTP multi-fibre female connectors. Optcore Furthermore, the four independent 850 nm VCSEL laser lanes each carry 10 Gbps for a total aggregate throughput of 40 Gbps — making this module the standard choice for 40G switch-to-switch, switch-to-server, and inter-rack connections.

4x10G Breakout Mode — Maximise Infrastructure Value

The QSFP-40G-SR4 also operates in a 4x10G breakout mode for interoperability with 10GBASE-SR interfaces, achieved using an external 12-fibre parallel to 2-fibre duplex breakout cable connecting the module to four 10GBASE-SR optical interfaces. Optcore Consequently, a single 40G port on a Cisco Nexus or Catalyst switch connects to four independent 10G server or switch ports — maximising port utilisation and protecting existing 10G infrastructure investments during 40G migration. Additionally, Cisco optimises the QSFP-40G-SR4’s transmit and receive optical characteristics to prevent receiver overload when operating in 4x10G mode, guaranteeing worry-free interoperability with all standard 10GBASE-SR interfaces. Optcore

Digital Diagnostics & Platform Compatibility

Moreover, digital diagnostics functions are available via the I2C interface, including Tx and Rx power monitoring Cisco — giving network administrators real-time visibility into module health and optical link performance. The module operates on a single 3.3V power supply and complies fully with the QSFP+ MSA (SFF-8436) and IEEE 802.3ba 40GBASE-SR4 standard. Maximum outer dimensions for the QSFP connector module are 13.5 x 18.4 x 72.4 mm Zorinstechnologies, fitting cleanly into any QSFP+ port. Whether you are deploying a 40G data centre fabric, migrating from 10G to 40G infrastructure, or connecting high-performance servers to core switches, the Cisco / QSFP-40G-SR4 / 40GBASE-SR4 4 Lanes 850 nm MMF delivers the speed, flexibility, and Cisco platform reliability your network demands. To check availability, check our stock. For full official specifications, visit the Cisco 40GBASE QSFP Modules official datasheet page.

Key Features:

• 40 Gbps — 4 x 10G Parallel Lanes at 850 nm — Four independent 850 nm VCSEL laser channels each deliver 10 Gbps for a total 40 Gbps aggregate throughput over 12-fibre MPO/MTP multimode fibre cables
• 100 m OM3 / 150 m OM4 MMF Reach — Supports 100 m on laser-optimised OM3 and 150 m on OM4/OM5 multimode fibre, covering all standard data centre and campus inter-rack distances
• 4x10G Breakout Mode — Full 10GBASE-SR Interoperability — Splits a single 40G QSFP+ port into four independent 10G SFP+ connections via MPO-to-LC duplex breakout cable, protecting 10G infrastructure investment
• Digital Optical Monitoring (DOM/DDM) — Real-time Tx/Rx power monitoring via I2C interface for proactive optical link diagnostics and fault prevention
• IEEE 802.3ba & QSFP+ MSA Compliant — Genuine Cisco — Fully compliant with 40GBASE-SR4 standard and QSFP+ MSA SFF-8436, validated for seamless integration into Cisco Nexus, Catalyst, and ASR platforms