Understanding 10GbE, 40GbE, and 100GbE Short Range Optical Transceivers

Demands for higher speeds in both telecom and datacom network are rapidly increasing due to the needs for high-bandwidth consumption. Currently the 10GbE system is still the dominant deployment in the optical transceiver market. But the 40GbE and 100GbE have come from behind since last year. Short range optical transceiver is the most commonly used type in data center or other indoor applications. This post is going to illustrate the short range optical transceivers for 10GbE, 40GbE and 100GbE.

10GBASE-SR Optical Transceiver

10GBASE-SR (Short Range) is a port type for multimode fiber and uses 850nm lasers. Its 64b/66b PCS (Physical Coding Sublayer) is defined in IEEE 802.3 Clause 49 and its PMD (Physical Medium Dependent) in Clause 52. It delivers serialized data at a line rate of 10.3125 Gbps. The range depends on the type of multimode used, e.g. OM1 for 33 meters. The 10GBASE-SR transceiver uses SFP+ form factor with duplex LC connector. It generally supports a link length of 26 meters on standard Fiber Distributed Data Interface (FDDI)-grade multimode fiber and can also support link length up to 400 meters while using OM4 multimode fiber.


40GBASE-SR4 Optical Transceiver

40GBASE-SR4 (Short Range) is a port type for multimode fiber and uses 850 nm lasers. Its 64b/66b PCS is defined in IEEE 802.3 Clause 82 and its PMD in Clause 86. It uses four lanes of multimode fiber delivering serialized data at a rate of 10.3125 Gbps per lane. 40GBASE-SR4 optical transceiver is QSFP+ form factor, primarily enabling high-bandwidth 40GbE optical links over 12-fiber parallel fiber terminated with MPO/MTP multifiber female connectors. In general, it can support link lengths of 100 and 150 meters, respectively on OM3 and OM4 multimode fibers. In addition, there is a longer range variant called 40GBASE-CSR4 QSFP+, which can support up to 400 meters over OM4 fiber. In addition, using 12-fiber MPO/MTP to 6 duplex LC or 8-fiber MPO/MTP to 4 duplex LC breakout cable, the 40GBASE-SR4 interface can be divided into four 10GBASE-SR interfaces.


100GBASE-SR10 Optical Transceiver

The IEEE P802.3ba Task Force developed a single architecture capable of supporting both 40bE and 100GbE. 100GBASE‐SR10, which is defined as 10 wavelengths across 10 parallel fiber paths at 10Gbps on multimode fiber. CFP is the typical representative form factor of 100GBASE-SR10. The 10GBASE-SR10 CFP uses 24-fiber MPO/MTP optical interface, enabling high-bandwidth 100GbE links over 24-fiber ribbon cables terminated with MPO/MTP-24 connectors. Alternatively, 2x 12-fiber MPO connector interface can be used where one connector is used for Receive while the other for Transmit. The 100GBASE-SR10 CFP can supports link lengths of 100 meters and 150 meters respectively on laser-optimized OM3 and OM4 multifiber cables. Additionally, it can be used in 10x 10GbE mode along with ribbon to duplex fiber breakout cables for connectivity to ten 10GBASE-SR optical interfaces.


Note: Currently, the 100G QSFP28 SR4 transceiver is available, which is designed for use in 100GbE links over multimode fiber but is implemented with four 25-Gbps lanes. As it is based on 25GbE, we would not explain it in details here.

After learning the above contents, do you have a better understanding on the 10GbE, 40GbE and 100GbE short range optical transceivers? For more knowledge about fiber optic transceivers, please continue to pay attention to the blog updates or visit this page.

Resource: QSFP28 SR4 Optical Transceiver Module Overview

                   SFP-10G-SR Fiber Transceiver Choosing Tips

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