400GBASE-ER8 Application Overview


400GBASE-ER8: 400 Gb/s wavelength‑division multiplexed (WDM) PAM4 serial transmission over 2 single‑mode optical fibers, with reach up to at least 40 km

400GBASE-ER8 supports eight long wavelength WDM 4‑level pulse amplitude modulated (PAM4) serial transmission over duplex (2‑fiber) single‑mode optical fiber cabling. The application’s equivalent symbol rate is 425 GBd per lane (PAM4 maps pairs of bits into a single symbol) lane and the supported distance varies according to the type of single‑mode cable used. Network equipment interface connections include a duplex optical fiber connector and a standard socket into which physical (PHY) layer transceiver modules may be plugged.

  • Connector type: LC
  • Transceiver module: QSFP-DD
  • Defined in clause 122 of the IEEE 802.3 Standard for Ethernet
  • Initially published as IEEE Std 802.3cn™: Physical Layers and Management Parameters for 50 Gb/s, 200 Gb/s, and 400 Gb/s Operation over Single‑Mode Fiber in 2019

Optical Fiber Cabling (Channel) Characteristics:

Parameter OS1a Indoor/Outdoor OS2
Operating wavelengths: 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
Specification wavelength: 1310 nm
Insertion loss (min)1: 10.0 dB
Insertion loss (max): 18.0 dB
Cabled fiber attenuation (max): 1.0 dB/km 0.5 dB/km 0.4 dB/km
Operating range2: 2 m to 15 km3 2 m to 30 km3 2 m to 40 km4
1 Minimum channel insertion loss may be achieved by use of an optical attenuator.
2 Maximum operating ranges are calculated using a 2.0 dB connection and splice loss allocation.
3 Operating range for cabled fibers having other than 0.4 dB/km attenuation is not specified by IEEE 802.3. These calculations are provided for information only.
4 Links longer than 30 km for the same link power budget are considered engineered links and must not exceed specified insertion loss.

Key Application Capabilities:

  • Defines a 400 Gb/s PHY using eight WDM lanes for operation over at least 40 km of SMF
  • 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

Related Applications:

The IEEE P802.3cn Task Force also specified the following PAM4, 53.125 GBd symbol rate Ethernet applications:

Application    Operating    Wavelength(s) Media Operating Range1
50GBASE-ER 1310 nm Single-mode up to 40 km3
200GBASE-ER4 four WDM2 Single-mode up to 40 km3
1 Supported distance varies according to the type of optical fiber cable used.
2 1295.56 nm, 1300.05 nm, 1304.58 nm, and 1309.14 nm
3 Links longer than 30 km for the same link power budget are considered engineered links and must not exceed specified insertion loss.

Back to TIA FOTC IEEE 802.3 Single-mode Optical Fiber Ethernet Standards Explorer