40GBASE-LR4 Application Overview


40GBASE-LR4: 40 Gb/s wavelength-division multiplexed (WDM) serial transmission over 2 single‑mode optical fibers, with reach up to at least 10 km

40GBASE-LR4 supports four long wavelength WDM serial transmission over duplex (2‑fiber) single‑mode optical fiber cabling. The application’s equivalent symbol rate is 41.25 GBd per 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 standard sockets into which physical (PHY) layer transceiver modules may be plugged.

  • Connector type: LC
  • Transceiver module: CFP, QSFP+
  • Defined in clause 87 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:

Parameter OS1a Indoor/Outdoor OS2  
Operating wavelengths: 1271 nm, 1291 nm, 1311 nm, and 1331 nm  
Specifcation wavelength: 1310 nm  
Insertion loss (max): 6.7 dB  
Cabled fiber attenuation (max): 1.0 dB/km 0.5 dB/km 0.4 dB/km  
Operating range2: 2 m to 4 km1 2 m to 8 km1 2 m to 10 km  
1 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.
2 Maximum operating ranges are calculated using a 2.0 dB connection and splice loss allocation.

Key Application Capabilities:

  • Defines a 40 Gb/s PHY using four WDM lanes for operation over at least 10 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 10-12 at the MAC/PLS service interface

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-SR4 850 nm Multimode up to 150 m
100GBASE-CR10 Copper Twinax up to 7 m
100GBASE-ER4 four WDM2 Single-mode up to 40 km3
100GBASE-KR10 Backplane
100GBASE-LR4 four WDM2 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 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