400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0

400G-BD4.2 Multimode Fiber 8x50Gbps
Technical Specifications
As Defined by the “400G BiDi MSA”

Revision 1.0 September 1, 2018
Chair – Mark Nowell, Cisco
Co-Chair –John Petrilla, FIT
Editor - Randy Clark, FIT

The following companies were members of the 400G BiDi MSA at the release of this specification:

Company
Alibaba
Broadcom
Cisco
Corning Incorporated
Foxconn Interconnect Technology
InnoLight Technology
Inphi Corporation
Sumitomo ElectricReleases:
Revision
Date
1.009/01/18

Description
First publication

Page 1 of 10400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
CONTENTSCONTENTS ...................................................................................................................... 2TABLES ............................................................................................................................ 3
FIGURES ......................................................................................................................... 312GENERAL .................................................................................................................

4

1.1 SCOPE .........................................................................................................
1.2 400G-BD4.2 MODULE BLOCK DIAGRAM ...................................................
1.3 FUNCTIONAL DESCRIPTION ......................................................................
1.4 MODULE HARDWARE SIGNALING PINS ...................................................
1.5 MODULE MANAGEMENT AND LOW SPEED ELECTRICAL INTERFACE ..
1.6 HOST FEC REQUIREMENTS .......................................................................
1.7 MODULE HIGH SPEED ELECTRICAL CHARACTERISTICS .......................
1.8 MODULE MECHANICAL DIMENSIONS AND REQUIREMENTS .................

44455555400G-BD4.2 OPTICAL SPECIFICATIONS................................................................. 52.1 OPTICAL SPECIFICATIONS.......................................................................... 52.1.1
2.1.2
2.1.33DEFINITION OF OPTICAL PARAMETERS AND MEASUREMENT METHODS ...... 93.1
3.2
3.34400G-BD4.2 Transmit Optical Specifications................................ 6400G-BD4.2 Receive Optical Specifications................................. 7400G-BD4.2 Illustrative Link power Budget................................... 8400G-BD4.2 Optical Parameter and Measurement Methods ...... 9400G-BD4.2 Optical Lane Assignments ....................................... 9400G-BD4.2 MDI (Medium Dependent Interface) Requirements .. 9400G-BD4.2 MODULE COLOR CODING.................................................................... 10Page 2 of 10

400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0TABLES
Table 2-1: 400G-BD4.2 Required Optical Link Distance Operating Range ...................... 6
Table 2-2: 400G-BD4.2 Transmit Characteristics ............................................................. 6
Table 2-3: 400G-BD4.2 Receive Characteristics .............................................................. 7
Table 2-4: 400G-BD4.2 Illustrative Power Budget............................................................. 8Table 3-1: 400G-BD4.2 Electrical to Optical Lane Mapping for MPO Connector
8Table 4-1: 400G-BD4.2 Module Color Coding .................................................................. 10FIGURES
Figure 1-1: Block Diagram for 400G-BD4.2 Transmit and Receive Paths ....................... 4Figure 3-1: Optical Lane Assignments for 400G-BD4.2 .................................................. 9Page 3 of 10

400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
1 GENERAL
1.1 SCOPE
This Specification defines the 400G-BD4.2 8x50 Gbps MMF optical interface for Ethernet
applications. Using the 400G-BD4.2 specification, two transceivers communicate overmultimode optical fibers (MMF) of lengths from 0.5 meters to 70 meters (OM3), 100m (OM4)
and 150m (OM5). The transceiver electrical interface is not defined in this specification, but istypically deployed using eight lanes in each direction with a PAM4 encoded, nominal signaling
rate of 26.5625 GBd (53.125 Gbps) in each direction (400GAUI-8 C2M per IEEE Std 802.3TM2018 Annex 120E). Forward error correction (FEC) is required to be implemented by the host inorder to ensure reliable system operation and is accommodated in the nominal signaling rate.
A variety of form factors for 400G-BD4.2 transceivers are possible (such as QSFP-DD andOSFP) and none are precluded by this MSA.

1.2 400G-BD4.2 MODULE BLOCK DIAGRAMNOTE – Specification of the CDR function is beyond the scope of this specification.
NOTE: See Table 3-1 and Figure 3-1 for Electrical to Optical Lane Mapping for MPO Receptacle

Figure 1-1: Block Diagram for 400G-BD4.2 Transmit and Receive Paths

1.3 FUNCTIONAL DESCRIPTION400G-BD4.2 modules comply with the requirements of this document and have the following
common features: eight optical transmitters and eight optical receivers in a bi-directional opticalconfiguration (four of the transmitters using a wavelength range of 844nm to 863nm, λ1, and fourof the transmitters using a wavelength range of 900nm to 918nm, λ2), a signal detect for each
optical receiver and a twelve channel MPO fiber optic connector (only eight fibers total arerequired) using multimode optical fiber.

Page 4 of 10

400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
1.4 MODULE HARDWARE SIGNALING PINS
Hardware signals and associated contact assignments are specified in the respective form
factor specifications (such as QSFP-DD or OSFP).

1.5 MODULE MANAGEMENT AND LOW SPEED ELECTRICAL INTERFACE
The module management and low speed electrical interface is specified in the respective form
factor specifications (such as QSFP-DD or OSFP).

1.6 HOST FEC REQUIREMENTS
The host system is required to enable FEC for the module electrical interface in accordance withIEEE Std 802.3TM-2018 Clause 122.1.1 and IEEE Std 802.3TM-2018 Annex 120E (400GAUI-8).
The option to disable the host FEC correction function is not addressed in this specification.
Use of supplemental FEC capability within the optical module is not addressed in thisspecification.

1.7 MODULE HIGH SPEED ELECTRICAL CHARACTERISTICS
The detailed high speed electrical characteristics are not defined in this specification. The
module electrical interface is intended to be in accordance with IEEE Std 802.3TM-2018 Annex
120E (400GAUI-8).

1.8 MODULE MECHANICAL DIMENSIONS AND REQUIREMENTS
Module mechanical dimensions and requirements are specified in the respective form factorspecifications (such as QSFP-DD or OSFP).

2 400G-BD4.2 OPTICAL SPECIFICATIONS
2.1 OPTICAL SPECIFICATIONS
The optical link distance operating range for the 400G-BD4.2 is defined in Table 2-1. A
compliant PMD operates on multimode fibers according to the specifications in Table 2-4. A
PMD that exceeds the required link distance operating range while meeting all opticalspecifications is considered compliant.
Table 2-1: 400G-BD4.2 Required Optical Link Distance Operating Range
PMD Type

OM3 Operating Range

OM4 Operating Range

OM5 Operating Range

400G-BD4.2

0.5 m to 70 m

0.5 m to 100 m

0.5 m to 150 m

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400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
For the 400G-BD4.2 PMD, the bit error ratio (BER) when processed by the PMA (IEEE Std802.3TM-2018 Clause 120) shall be less than 2.4 × 10–4 provided that the error statistics aresufficiently random that this results in a frame loss ratio of less than 1.7 × 10–12 for 64-octet
frames with minimum inter-packet gap when additionally processed by the PCS (IEEE Std802.3TM-2018 Clause 119). For a complete Physical Layer, the frame loss ratio may be
degraded to 6.2 × 10–11 for 64-octet frames with minimum inter-packet gap due to additional
errors from the electrical interfaces. If the error statistics are not sufficiently random to meet thisrequirement, then the BER shall be less than that required to give a frame loss ratio of less than
1.7 × 10–12 for 64-octet frames with minimum inter-packet gap.

2.1.1 400G-BD4.2 Transmit Optical Specifications
Each lane of a 400G-BD4.2 transmitter shall meet the specifications in Table 2-2.
eTable 2-2: 400G-BD4.2 Transmit Characteristics (TP2 )Parameter

400G-BD4.2 Value

Unit

Signaling Rate, each lane (range)

26.5625 ± 100 ppm

GBd

λ1 Center Wavelength [Tx1, Tx3, Tx5, Tx7], each lane (range)

844 to 863

nm

λ2 Center Wavelength [Tx2, Tx4, Tx6, Tx8], each lane (range)

900 to 918

nm

Modulation Format

PAM4

RMS Spectral Width, each lane a (max)

0.6

nm

Average Launch Power, each lane (max)

4dBm

Average Launch Power, each lane (min)- 6.5dBm

Outer Optical Modulation Amplitude (OMAouter), each lane (max)

3dBm

Outer Optical Modulation Amplitude (OMAouter), each lane b (min)

- 4.5

dBm

OMAouter - TDECQ, each lane (min)

- 5.9

dBm

Transmitter and Dispersion Eye Closure for PAM4 (TDECQ), each lane max

4.5dB

TDECQ – 10log10(Ceq), each lane (max) c

4.5

dB

Average Launch Power of OFF Transmitter, each lane (max)

-30

dBm

Extinction Ratio, each lane (min)3dB

Transmitter Transition Time, each lane (max)34

ps

RIN12OMA, each lane (max)

-128

dB/Hz

Optical Return Loss Tolerance, each lane (max)

12dB≥ 86% at 19um≤ 30% at 4.5um

Encircled Flux, each lane dTest methodology is assumed to be based on IEEE P802.3cdTM/D3.4 Clause 138.8.
aRMS spectral width is the standard deviation of the spectrum.
bEven if the TDECQ < 1.4 dB, the OMAouter (min) must exceed this value.
cCeq is a coefficient defined in IEEE Std 802.3TM-2018 Clause 121.8.5.8 which accounts for the reference equalizer
noise enhancement.
dIf measured into type A1a.2, or type A1a.3, or type A1a.4, 50 um fiber in accordance with IEC 61280-1-4:2009.
e
TP2 as defined in IEEE P802.3cdTM/D3.4 Figure 138-2.

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400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
2.1.2 400G-BD4.2 Receive Optical Specifications
Each lane of a 400G-BD4.2 receiver shall meet the specifications in Table 2-3.
gTable 2-3: 400G-BD4.2 Receive Characteristics (TP3 )Parameter

400G-BD4.2 Value

Unit

Signaling Rate, each lane (range)

26.5625 ± 100 ppm

GBd

λ1 Center Wavelength [Rx1, Rx3, Rx5, Rx7], each lane (range)

844 to 863

nm

λ2 Center Wavelength [Rx2, Rx4, Rx6, Rx8], each lane (range)

900 to 918

nm

Modulation Format

PAM4

Damage Threshold, each lane a (min)5dBm

Average Receive Power, each lane (max)

4dBm

Average Receive Power, each lane b (min)

- 8.5

dBm

Receive Power (OMAouter), each lane (max)

3dBm

Receiver Reflectance, each lane (max)

-12

dB

Stressed Receiver Sensitivity (OMAouter), each lane c (max)

-3.5

dBm

max (-6.6, SECQ - 8)

dBm

Stressed Eye Closure (SECQ), lane under test

4.5

dB

SECQ – 10log10(Ceq), lane under test (max) f

4.5dB

OMAouter of each aggressor lane

3dBm

Receiver Sensitivity (OMAouter), each lane d (max)Conditions of Stressed Receiver Sensitivity Test: eTest methodology is assumed to be based on IEEE P802.3cdTM/D3.4 Clause 138.8.
aThe receiver shall be able to tolerate, without damage, continuous exposure to an optical input signal having thisaverage power level on one lane. The receiver does not have to operate correctly at this input power.
bAverage receive power, each lane (min) is informative and not the principal indicator of signal strength. A received
power below this value cannot be compliant; however, a value above this does not ensure compliance.
c
Measured with a conformance test signal at TP3 (see IEEE P802.3cdTM/D3.4 Clause 138.8.8) for the BER specified in
section 2.1.
dReceiver sensitivity is informative and is defined for a transmitter with a value of SECQ up to 4.5dB.
e
These test conditions are for measuring stressed receiver sensitivity. They are not characteristics of the receiver.
fCeq is a coefficient defined in IEEE Std 802.3TM-2018 Clause 121.8.5.8 which accounts for the reference equalizer
noise enhancement.
gTP3 as defined in IEEE P802.3cdTM/D3.4 Figure 138-2.

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400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
2.1.3 400G-BD4.2 Illustrative Power Budget
An illustrative power budget and penalties for 400G-BD4.2 are shown in Table 2-4.
Table 2-4: 400G-BD4.2 Illustrative Power Budget
Parameter

OM3 Value

OM4 Value

OM5 Value

Unit

Effective Modal Bandwidth at 850nm a200047004700

MHz kmEffective Modal Bandwidth at 918nm

1210 b1850 b2890 aMHz kmPower Budget (for max TDECQ)

6.6dB

Operating Distance

70100150mChannel Insertion Loss c

1.8

1.9

2.0dB

Allocation for Penalties d (for max TDECQ)
Additional Insertion Loss Allowed

4.6
0.2

a0.1dB0dB

Per IEC 60793-2-10.
Per draft IEC 60793-2-10 (subject to confirmation by TIA and IEC).
c
The channel insertion loss is calculated using the maximum distance specified and the cabled optical fiber attenuationof 3.5 dB/km at 850 nm, plus an allocation of 1.5 dB for connection and splice loss (as given in IEEE P802.3cdTM/D3.4
Clause 138.10.2.2.1).
dLink penalties are used for link budget calculations. They are not requirements and are not meant to be tested.
bPage 8 of 10

400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
3 DEFINITION OF OPTICAL PARAMETERS AND
MEASUREMENT METHODS
3.1 400G-BD4.2 Optical Parameter and Measurement Methods
All 400G-BD4.2 optical measurements shall be made using the Optical Parameter andMeasurement Methods specified in IEEE P802.3cdTM/D3.4 Clause 138.8, using Table 2-2 of thistechnical specification for the center wavelength and RMS spectral width.

3.2 400G-BD4.2 Optical Lane Assignments
Lane assignments for optical connectors are documented in relevant transceiver specifications(e.g. QSFP-DD and OSFP).
MPO (8 fiber) lane ordering is shown below for reference. Optical lane Tx1 is the output opticalsignal of transceiver electrical input signals Tx1p and Tx1n; likewise for Tx2 – Tx8. Optical lane
Rx1 is the input optical signal for transceiver electrical output signals Rx1p and Rx1n; likewisefor Rx2 – Rx8. Optical wavelengths are defined in Table 2-2 and Table 2-3.
Table 3-1: 400G-BD4.2 Electrical to Optical Lane Mapping for MPO Connector

FerruleSignals

ModuleElectrical Tx
Signals

TR1TR2
TR3
TR4

Tx1, Rx2
Tx3, Rx4
Tx5, Rx6
Tx7, Rx8

Tx1p/nTx3p/nTx5p/nTx7p/nRx2p/nRx4p/nRx6p/nRx8p/n

RT4
RT3
RT2
RT1

Tx8, Rx7
Tx6, Rx5
Tx4, Rx3
Tx2, Rx1

Tx8p/nTx6p/nTx4p/nTx2p/nRx7p/nRx5p/nRx3p/nRx1p/nModule Optical I/O

ModuleElectrical RxSignals

Figure 3-1: 400G-BD4.2 Lane Ordering for MPO Optical Connector

3.3 400G-BD4.2 MDI (Medium Dependent Interface) Requirements
The 400G-BD4.2 MDI shall meet the requirements of IEEE P802.3cdTM/D3.4 Clause 138.10.3.3.

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400G BiDi MSA 400G-BD4.2 Technical Specification Rev 1.0
4 400G-BD4.2 MODULE COLOR CODING
Transceiver modules compliant to these 400G-BD4.2 specifications shall use a color code toindicate the application. This color code can be on a module latch, pull tab, or other visible
feature of the module when installed in a system. The color code scheme is specified in Table
4-1.
Table 4-1: 400G-BD4.2 Module Color Coding
Color CodeApplication

Beige

400G-BD4.2

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