400GBASE-SR16 Application Overview


400GBASE-SR16: 400 Gb/s PAM4 parallel transmission at 850 nm over 32 multimode optical fibers, with reach up to at least 100 m

400GBASE-SR16 supports short wavelength parallel transmission over sixteen lanes (32‑fibers) of multimode optical fiber cabling. The application’s nominal symbol rate is 25.78125 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 a standard socket into which a physical (PHY) layer transceiver module may be plugged.

  • Connector type: MPO/MTP
  • Transceiver module: CFP8
  • Defined in clause 123 of the IEEE 802.3 Standard for Ethernet
  • Initially published as IEEE Std 802.3bs: Media Access Control Parameters, Physical Layers, and Management Parameters for 200 Gb/s and 400 Gb/s Operation in 2017

Optical Fiber Cabling (Channel) Characteristics:

Parameter OM3 OM4 OM5 Unit
Operating wavelength: 850 nm
Modal bandwidth (min): 2,000 4,700 MHz∙km
Operating range: 0.5 to 70 0.5 to 100 m
Insertion loss (max):: 1.8 1.9 dB
Cabling skew (max): 134 ns
Cabling skew variation: 3.4 ns

Key Application Capabilities:

  • Defines a sixteen-lane 400 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 10-13 at the MAC/PLS service interface (or the frame loss ratio equivalent)
  • Supports optional Energy-Efficient Ethernet operation

Related Applications:

The IEEE P802.3bs Task Force also specified the following 200 Gb/s and 400 Gb/s Ethernet applications:

Application    Operating    Wavelength(s) Media Operating Range1
200GBASE-DR4 1310 nm Single-mode up to 500 m
200GBASE-FR4 four WDM2 Single-mode up to 2 km
200GBASE-LR4 four WDM3 Single-mode up to 10 km
400GBASE-DR4 1310 nm Single-mode up to 500 m
400GBASE-FR8 eight WDM4 Single-mode up to 2 km
400GBASE-LR8 eight WDM4 Single-mode up to 10 km
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 1273.54 nm, 1277.89 nm, 1282.26 nm, 1286.66 nm, 1295.56 nm, 1300.05 nm, 1304.58 nm, and 1309.14 nm

Back to TIA FOTC IEEE 802.3 Multimode Optical Fiber Ethernet Standards Explorer