Application Note
Fiber Optic Link Budget in the CommScope Era™ System
Key factors that should be considered when designing the fiber links for the
CommScope Era system.
DCCS, 10/2019
Application Note
Contents
1.
Overview
3
2.
Minimum Optical Path Loss
3
3.
Maximum Optical Path Loss
3
4.
Optical Link Loss
3
5.
Minimum Performance Levels
4
6.
CommScope SFP+ Module Specifications
4
7.
Additional Information
6
Fiber Optic Link Budget in the CommScope Era™ System
2
Application Note
1.
Overview
When designing the fiber links for the CommScope Era system, is important to consider all the factors that can affect link
performance. These include TX optical power, RX sensitivity, the fiber length, the wavelength, the number of splices, and
the number of connectors. This application note briefly describes the key factors that should be considered.
2.
Minimum Optical Path Loss
The optical power applied to the RX input of the SFP+ module must be less than the Receiver Overload threshold. In some
cases, the Receiver Overload is less than or equal to the maximum TX Optical Power, which allows a very short fiber jumper
to be used to connect a TX to RX power; however, in other cases the TX Power exceeds the Receiver Overload threshold, so
a minimum amount of optical attenuation must be applied between the TX output and RX input to prevent overdriving the
RX input. See Table 2: for the specifications for the various SPF+ modules that are qualified for use with the Era system.
Optical Fiber Path Loss >= TX Optical Power Max - Receiver Overload
If the path loss is below the amount of attenuation needed to prevent exceeding the Receiver Overload threshold, then
additional attenuation must be added in the link to prevent overdrive. This can be done by adding additional fiber or using
an inline optical attenuator.
3.
Maximum Optical Path Loss
The optical power received at the RX input must be greater than the RX Sensitivity. The RX power is equal to the minimum
TX power reduced by any optical attenuation in the TX-RX path. It is good design practice to provide additional link margin
when designing the fiber links.
Maximum Optical Path Loss<= TX Optical Power Min - RX Sensitivity - Link Margin
4.
Optical Link Loss
Optical loss is calculated by adding the attenuation due to the length of the fiber optic cable, the number of connectors in
the link, and the number of splices. If there are other optical devices in the link, then their attenuation needs to be included
as well (mux, demux, add/drop, etc.).
Optical Link Loss = fiber length(km) * optical attenuation/km
+ Splice Loss * Number of splices
+ Connector Loss * Number of Connectors
Fiber Optic Link Budget in the CommScope Era™ System
3
Application Note
5.
Minimum Performance Levels
The values below are the minimum performance specifications for fiber optic components noted in ANSI/TIA/EIA-568-C.3
Optical Fiber Cabling Components, with key performance specifications shown in Table 1: Minimum Performance of Optical
Components.
Table 1: Minimum Performance of Optical Components
Parameter
Mated connector pair
Splice
50/125 um Multimode OM3
Single-mode, Indoor-Outdoor
Single-mode, Inside Plant
Single-mode, Inside Plant
1
6.
Minimum Performance1
0.75 dB
0.3 dB
3.5dB/km @850nm
0.5dB/km @1310nm, 1550 nm
1.0dB/km @1310nm, 1550 nm
0.5dB/km @1310nm, 1550 nm
Actual performance of may be better than the minimum performance values noted.
CommScope SFP+ Module Specifications
The following SFP+ modules are available from CommScope. These SFP+ modules have been tested by CommScope to
ensure that they meet the requirements of an Era and ION-E system. This list was current at the time that this application
note was published but is subject to change.
Table 2: CommScope SFP+ Module Specifications
TX Optical
Power Min
TX Optical
Power
Max
RX
Sensitivity
@10.3Gb/s
Receiver
Sensitivity
(OMA) @
10.3Gb/s
Receiver
Overload
CommScope
Part Number
Description
7660511
SFP+, 10GBase-SR, (MM)
-7.3 dBm
-1 dBm
-9.9 dBm
-11.1 dBm
-1 dBm
0 dBm
7680813
SPF+, LR
-8.2 dBm
+0.5 dBm
-14.4dBm
-12.6dBm
0.5 dBm
0 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
-1 dBm
4 dBm
-15.8 dBm
-12.6 dBm
-1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
7801330
7801340
7801342
7801344
7801360
7801363
7801365
7801367
7803247
7803249
7803291
7803293
7803295
(SM)
SFP+ CWDM 1471 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1491 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1511 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1531 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1551 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1571 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1591 nm,
10G-BASE-ER/EW, 10GbE
SFP+ CWDM 1611 nm,
10G-BASE-ER/EW, 10GbE
IC SFP+ APSPC27B33CDL40
Transceiver
IC SFP+ APSPC29B33CDL40
Transceiver
IC SFP+ APSPC31B33CDL40
Transceiver
IC SFP+ APSPC33B33CDL40
Transceiver
IC SFP+ APSPC35B33CDL40
Transceiver
Fiber Optic Link Budget in the CommScope Era™ System
Minimum
Path Loss
4
Application Note
CommScope
Part Number
7803298
7803900
7803902
7803904
7803906
7832204
7832206
Description
IC SFP+ APSPC37B33CDL40
Transceiver
IC SFP+ APSPC39B33CDL40
Transceiver
IC SFP+ APSPC41B33CDL40
Transceiver
IC SFP+ APSPC43B33CDL40
Transceiver
IC SFP+ APSPC45B33CDL40
Transceiver
10G BIDI SFP+ TX1270/RX1330
40km I-temp
10G BIDI SFP+ TX1330/RX1270
40km I-temp
TX Optical
Power Min
TX Optical
Power
Max
RX
Sensitivity
@10.3Gb/s
Receiver
Sensitivity
(OMA) @
10.3Gb/s
Receiver
Overload
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-14.4 dBm
-12.6 dBm
+1 dBm
5 dBm
+1 dBm
+6 dBm
-13 dBm
-
+0.5 dBm
5.5 dBm
+1 dBm
+6 dBm
-13 dBm
-
+0.5 dBm
5.5 dBm
Fiber Optic Link Budget in the CommScope Era™ System
Minimum
Path Loss
5
Application Note
7.
Additional Information
For more information, please contact CMS Technical Support.
http://www.commscope.com/wisupport
commscope.com
Visit our website or contact your local CommScope representative for more information.
© 2019 CommScope, Inc. All rights reserved.
All trademarks identified by ® or ™ are registered trademarks or trademarks, respectively, of CommScope, Inc. This document is for planning purposes only and is not intended to modify or
supplement any specifications or warranties relating to CommScope products or services. CommScope is committed to the highest standards of business integrity and environmental
sustainability with a number of CommScope’s facilities across the globe certified in accordance with international standards, including ISO 9001, TL 9000, and ISO 14001. Further information
regarding CommScope’s commitment can be found at www.commscope.com/About-Us/Corporate-Responsibility-and-Sustainability.
AN-113833-EN (10/19)