Complete Guide to 40G QSFP+ Optical Transceivers and Cables
QSFP stands for Quad Small Form-factor Pluggable. 40G QSFP+ connectivity is an evolution of the 10G SFP+ connectivity. Indeed, the “Quad” of QSFP+ takes its meaning from the fact that 40GBase QSFP+ provides four channels of 10G.
Four different technologies can be found among the 40GBase QSFP+ family: Multi-mode Transceivers, Single-mode Transceivers, Direct Attached Cables and Active Optical Cables. Of course, each technology has its advantages and inconveniences. In this article, we are going to introduce each technology to help you select the most suitable 40G QSFP+ connectivity for your network.
Multi-mode transceivers are the low cost transceivers. QSFP+ SR4/eSR4 use more expensive non-standard MPO connectors which cancel out some of the cost savings of the transceiver. This approach is similar to using AOC cables, but here it is possible to use structured cabling.
40G QSFP+ SR4
The 40GBase QSFP+ SR4 transceiver supports connections of up to 100 meters over multi-mode fiber and uses MPO connectors. The wavelength is 850nm.
40G QSFP+ eSR4
The 40GBase QSFP+ eSR4 is similar to QSFP+ SR4 transceiver, it also uses MPO connectors and 850nm wavelength but it supports connections of up to 300 meters over multi mode fiber.
40G QSFP+ LX4
The 40GBase QSFP+ LX4 transceiver can be used over multi-mode and single-mode. Over multi-mode it can reach up to 150 meters with OM3 cable. The differences with the SR4 and eSRA are the 1310nm wavelength and the standard LC connectors.
40G QSFP+ Bidi
The 40GBase QSFP+ Bidi has two 20G channels that supports connections up to 100 meters on OM3 and up to 150 meters on OM4. It uses LC Duplex connector and the wavelength is 850nm.
Single-Mode transceivers are more expensive than multi-mode transceivers but they allow to reach longer distance and most of them are using standard LC connectors.
40G QSFP+ LX4
The 40GBase QSFP+ LX4 transceiver can be used over multi-mode and single-mode. Over single-mode it can reach up to 2km. It uses 1310nm wavelength and LC connectors.
40G QSFP+ LR4
The 40GBase QSFP+ LR4 transceiver supports connections up to 10 km over single-mode fiber and uses standard LC connectors. The wavelength is 1310nm.
40G QSFP+ PSM4
The 40GBase QSFP+ PSM4 transceiver supports connections up to 10 km over single-mode fiber and uses non-standard MPO connectors. The wavelength is 1310nm.
40G QSFP+ ER4
The 40GBase QSFP+ ER4 transceiver supports connections up to 40 km over single-mode fiber and uses standard LC connectors. The wavelength is 1310nm.
Direct Attached Cables are a very common method for very short-range distance because of the their low-cost. Indeed, they are the cheapest solution for connecting 40G equipment. In addition, it is a one part product instead of the usually three part solution ( two transceivers and a cable), which reduces the problems associated with dirty connectors. DAC also consume less power compared to Active Optical Cables (AOC).
There are two types of DAC, the passive copper cable for distance from 0 to 5 meters and active copper cable for distance from 5 to 15 meters.
QSFP+ to QSFP+DAC
QSFP+ to 4 x 10G SFP+ fanout DAC
Active Optical Cables are comparable to using transceivers and separated cables. They can reach longer distance than DAC, up to 100 meters. They also are lighter and smaller than DAC.
QSFP+ to QSFP+AOC
QSFP+ to 4 x 10G SFP+ fanout AOC
|Technology||Standard||Optech Part Number||Features|
|Multi-Mode Transceivers||40G QSFP+ SR4||OPCS-MX1-85-CB||850nm, 100 meters, MPO|
|40G QSFP+ eSR4||OPCS-MX3-85-CB||850nm, 300 meters, MPO|
|40G QSFP+ LX4||OPCS-X02-13-CB||1310nm, 150 meters, LC|
|40G QSFP+ Bidi||OPCS-X02-13-CB||850nm, 100/150m, LC|
|Single-Mode Transceivers||40G QSFP+ LX4||OPCS-X02-13-CB||1310nm, 2km, LC|
|40G QSFP+ LR4||OPCS-S10-13-CB||1310nm, 10km, LC|
|40G QSFP+ PSM4||OPCS-S10-13-CBS||1310nm, 10km, MPO|
|40G QSFP+ ER4||OPCS-S40-13-CB||1310nm, 40km, LC|
|Direct Attached Cables||40G QSFP+ to QSFP+ DAC||OPQSFP-T-xx-P||xx= 0,5 to 7 meters|
|40G QSFP+ to 4 SFP+ DAC||OPQSFP-T-xx-P/SFPP/4||xx= 0,5 to 7 meters|
|Active Optical Cables||40G QSFP+ to QSFP+ AOC||OPQSFP-F-xx-AKA||xx= 1 to 100 meters|
|40G QSFP+ to 4 SFP+ AOC||OPQSFP-F-xx-A/SFPP/4||xx= 1 to 100 meters|
Optech products are compatible with all major switches and servers brands. You can check all the compatible lists here.
Optech is a leading company in developing and manufacturing Optical Transceivers and Cables solutions for Data Center and Telecom market. Since 2001, Optech has been offering accurate lead time and high quality products to customers.
Optech offers a broad range of networking and communication solutions in following categories: Optical Transceivers, SFP, 10G SFP+, 25G SFP28, 40G QSFP+, 100G QSFP28 , Direct Attach Cables (DAC), Active Optical Cables (AOC), Ethernet Media Converter, Fiber Optical Patchcord, BWDM, CWDM, DWDM Mux/Demux and Repeater products.
For more information you can visit www.optech.com.tw or contact us at firstname.lastname@example.org.