40GBASE-SR4 Application Overview
40GBASE‑SR4: 40‑Gb/s parallel transmission at 850‑nm over 8 multimode optical fibers, with reach up to at least 150 m
40GBASE‑SR4 supports short wavelength parallel transmission over four lanes (8-fibers) of multimode optical fiber cabling. The application’s nominal symbol rate is 10.3125 GBd per lane and the supported distance varies according to the type of multimode cable used. Network equipment interface connections include a multi-fiber push on (MPO) connector and standard sockets into which a physical (PHY) layer transceiver module may be plugged.
- Connector type: MPO/MTP
- Transceiver module: CFP, QSFP+
- Defined in clause 86 of the IEEE 802.3 Standard for Ethernet
- Initially published as IEEE Std 802.3ba™: Media Access Control Parameters, Physical Layers, and Management Parameters for 40 Gb/s and 100 Gb/s Operation in 2010
Optical Fiber Cabling (Channel) Characteristics:
| 40GBASE-SR4 | ||||
| Parameter | OM3 | OM4 | OM5 | Unit |
| Operating wavelength: | 850 | nm | ||
| Modal bandwidth (min): | 2,000 | 4,700 | MHz∙km | |
| Operating range: | 0.5 to 100 | 0.5 to 150 | m | |
| Insertion loss (max): | 1.9 | 1.5 | dB | |
| Cabling skew (max): | 79 | ns | ||
| Cabling skew variation: | 2.4 | ns | ||
Key Application Capabilities:
- Defines a four-lane 40 Gb/s PHY for operation over at least 100 m of MMF
- Supports full-duplex operation only
- Preserves the Ethernet frame format utilizing the Ethernet MAC
- Preserves minimum and maximum FrameSize of current 802.3 Standard for Ethernet
- Provides appropriate support for optical transport networks (OTNs)
- Supports a BER of better than or equal to 10-12 at the MAC/PLS service interface (or the frame loss ratio equivalent)
Related Applications:
The IEEE P802.3ba Task Force also specified the following 40 Gb/s and 100 Gb/s Ethernet applications::
| Application | Operating Wavelength(s) | Media | Operating Range1 |
| 40GBASE-CR4 | – | Copper Twinax | up to 7 m |
| 40GBASE-KR4 | – | Backplane | – |
| 40GBASE-LR4 | four WDM2 | Single-mode | up to 10 km |
| 100GBASE-CR10 | – | Copper Twinax | up to 7 m |
| 100GBASE-ER4 | four WDM3 | Single-mode | up to 40 km4 |
| 100GBASE-KR10 | – | Backplane | – |
| 100GBASE-LR4 | four WDM3 | Single-mode | up to 10 km |
| 100GBASE-SR10 | 850 nm | Multimode | up to 150 m |
| 1 Supported distance varies according to the type of optical fiber cable used. 2 1271 nm, 1291 nm, 1311 nm, and 1331 nm 3 1295.56 nm, 1300.05 nm, 1304.58 nm, and 1309.14 nm 4 Links longer than 30 km for the same link power budget are considered engineered links and must not exceed specified insertion loss. |
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Back to TIA FOTC IEEE 802.3 Multimode Optical Fiber Ethernet Standards Explorer