As the requirement of higher transfer speeds increases continuously, more and more users tend to adopt optical solutions. As two prevailing solutions, 40G QSFP+ optical transceivers and 40G DAC/AOC cables are favored by users when deploying 40GbE. This article will focus on 40G optical transceivers of FS, including 40G QSFP+ transceivers and 40G DAC/AOC cables, and will also eliminate some of the customers' confusion in the closing part.
FS 40GBASE transceivers cover complete modules for Generic equipment, major brands' routers, and switches, and non-major brands' devices. A full range of third-party QSFP+ transceivers, DAC and AOC cables are compatible with major brands, such as Cisco, Juniper, Arista, Brocade, HPE, etc. For FS Generic 40G QSFP+ transceivers, they are made to support various 40GBASE protocols, like 40GBASE-SR4, 40GBASE-BiDi, 40GBASE-LR4, 40GBASE-UNIV, 40GBASE-ER4, etc. A detailed datasheet will be presented in the first part of introduction. Compared with QSFP+ transceivers, the direct attach cables (DAC) provide a cost-effective solution alternative for high-speed interconnections. 40G DAC and AOC cables with a great variety are also available to choose from FS.
The datasheet below presents some detailed specifications of our QSFP+/CFP optical modules. If you want to get more information, please visit 40G Transceiver Module: QSFP+ Module and CFP Module:
|FS P/N||Type||Cable Type||Wavelength||MAX. Distance||Connector Interface||DOM Support|
|QSFP-40G-SR4||40GBASE-SR4||MMF||850 nm||150 m||MTP/MPO||Yes|
|QSFP-40G-SR-BD||40GBASE-SR-BiDi||MMF||832 nm - 918 nm||150 m||LC duplex||No|
|QSFP-40G-CSR4||40GBASE-CSR4||MMF||850 nm||400 m||MTP/MPO||Yes|
150 m over MMF;
2 km over SMF
|QSFP-40G-PLRL4||40GBASE-PLRL4||SMF||1310 nm||1.4 km||MTP/MPO||Yes|
|QSFP-40G-PLR4||40GBASE-PLR4||SMF||1310 nm||10 km||MTP/MPO||Yes|
|WSP-Q40GLR4L||WSP-Q40GLR4L||SMF||1310 nm||2 km||LC duplex||Yes|
|QSFP-40G-LR4||40GBASE-LR4||SMF||1310 nm||10 km||LC duplex||Yes|
|QSFP-40G-ER4||40GBASE-ER4||SMF||1310 nm||40 km||LC duplex||Yes|
|CFP-40G-LR4||40GBASE-LR4||SMF||1310 nm||10 km||SC duplex||Yes|
|CVR-QSFP-SFP10G||QSFP+ to SFP+||N/A||N/A||N/A||N/A||Yes (10G module)|
FS QSFP+ 40G optical transceiver is a low profile, hot-pluggable transceiver used to connect switches, computers, and servers. Compared to CFP (C form-factor pluggable) modules, the QSFP+ module is more compact and more suitable for port-density applications. Considering the major factor affecting customers' purchase, the QSFP+ modules can be divided into two sections by virtue of different transmission distances.
For short transmission distances (＜1 km): transceivers that can only reach less than 1 km are designed for short-range transmission, and they are normally accompanied with multimode fibers. QSFP-40G-SR4 is one of the most competitive products that can reach 150 m over OM4 terminated with MTP connectors, suitable for many customers' needs. 40GBASE-SR-BiDi also supports 150 m transmission distance but has the unique capability to transmit full-duplex 40G traffic over one duplex MMF cable with LC connectors. As an enhanced version of the SR4 module, the QSFP-40G-CSR4 module can support longer data transmission—up to 400 m over OM4. It is noted that the QSFP-40G-UNIV module can only reach 150 m over MMF but its link lengths can reach from 500 m to 2 km (vary from different vendors) over SMF.
For long transmission distances (≥1 km): the data transmissions of the undermentioned transceivers range from 1.4 km to 10 km over single mode fiber cables. QSFP-40G-PLRL4 and QSFP-40G-PLR4 terminated with MTP/MPO connectors are both designed for parallel transmission. The former can support 1 km or 1.4 km transmission distance, while the latter's link length can reach up to 10 km. WSP-Q40GLR4L, QSFP-40G-LR4, and QSFP-40G-ER4 are all sharing the same working principle: multiplexing the four sending lanes onto one fiber strand and the four receiving lanes onto another single fiber strand instead of using one single fiber strand for each lane. Among them, the ER4 module can handle the longest transmission distance of data up to 40 km over SMF with duplex LC connectors. CFP-40G-LR4 is FS's main product of CFP modules, which is applied for 10 km transmission via SMF with SC duplex connectors.
Besides all the mentioned products, we also offer customized services to meet different demands by requiring compatible brands and device number.
FS 40G QSFP+ DAC Basics
40G QSFP+ DAC, short for 40G QSFP+ direct attach copper cable, is a high-speed twinax cable with QSFP+ connector on either end of the cable. The most fundamental use of DAC cables is for interconnections, usually involving switches, routers, and servers. The maximum transmission distance of QSFP DAC cables is 15 meters, which can meet the needs of emerging data centers and high-performance computing applications for short distances. Therefore, 40G QSFP+ DAC cables have been widely used in data centers and they're becoming more broadly used in network industries.
40G DAC cables can be classified into different types based on different standards. According to the internal structure, the division of 40G QSFP+ direct attach copper cables is twofold: QSFP+ passive DAC and QSFP+ active DAC. The prominent difference between them is whether it contains electronics for signal conditioning. QSFP+ passive DACs without electronics do not need power for internal electronics and do not consume any power or produce any heat, whereas QSFP+ active DACs within electronics require power to make the internal circuits work and can bridge longer distances. Besides, 40G QSFP+ direct attach copper cables can be mainly divided into two types—QSFP+ to QSFP+ DAC and QSFP+ to 4 SFP+ breakout DAC in view of the connector types on both ends.
FS 40G QSFP+ AOC Basics
Invented for data centers and high-performance computing applications, AOC assemblies are replacing copper technology to some degree on account of its stability and flexibility. Active optical cable (AOC) can be defined as a fiber patch cord terminated with optical transceivers on both ends. It uses electrical-to-optical conversion on the cable ends to improve the speed and distance performance of the cable without sacrificing compatibility with standard electrical interfaces.
At present, a variety of QSFP+ AOC cables have been launched for 40G applications in the market, such as 40G QSFP+ to QSFP+ AOC, 40G QSFP+ to 4 SFP+ breakout AOC and 40G QSFP+ to 8 LC breakout AOC. They are commonly used for short-range multi-lane data communication and interconnect applications between two devices, such as rack-to-rack, shelf-to-shelf interconnect, storage, hubs, switches, routers, servers, etc.
ALL in all, FS 40G QSFP+ cable has five types: QSFP+ to QSFP+ DAC cable, QSFP+ to QSFP+ AOC cable, QSFP+ to 4 SFP+ breakout DAC cables, QSFP+ to 4 SFP+ breakout AOC cables, and 40G QSFP+ to 8 LC breakout AOC cables. The table below has analyzed and summarized some factors that may help you to distinguish DAC, AOC and 2 transceivers with structured cabling.
|Parameter||DAC||AOC||2 Transceivers + Structured Cabling|
|Cable type||Twinax copper||Fiber optic||Fiber optic|
Depending on structured
|Power consumption||＜1 w (Passive DAC: ＜0.15 w)||1-2 w||1-2 w|
|Reach||＜10 m||100 m||Per TIA/IEEE Standard|
ToR (Top of Rack)
Middle of Row
End of Row
Middle of Row
End of Row
FS has available QSFP+ optical modules with a wide variety of types in stock and provides various DAC and AOC cables at the same time. Quality will always be FS's highest priority. We have precise and strict examinations of the transceivers before delivery, which includes incoming inspection, parameter testing, and connection to original-brand switches for distance and compatibility test. FS test center is equipped with a broad range of original switches from mainstream vendors like Cisco, Arista, HPE, Juniper, Brocade, etc. QSFP+ optical modules' performance, compatibility, and durability are tested rigorously to ensure product reliability. View more about our Test Assured Program.
Which QSFP 40G optical transceiver can be used for 4×10G?
40GBASE-SR4, 40GBASE-CSR4, 40GBASE-PLR4, and 40GBASE-PLRL4 are all using parallel technology with 4 lanes in each direction. These 40G transceivers can be split into 4x10G.
What cable type is needed for the PLRL4 and PLR4 transceivers?
PLR4 and PLRL4 modules use single-mode MTP-12 cables with MTP-12 APC (Angle polished connector) connectors.
What are the advantages and disadvantages of DAC and AOC cables?
There are some advantages of using a QSFP+ DAC cable: lower cost and power consumption, higher data transmission rate, strong interchangeability and “plug and play.” QSFP+ DAC cables also have their shortfalls: heavier weight and larger volume, limited distance, and difficult to manage. Here are some of the pros behind AOC cables: lighter weight, greater bandwidth, and EMI immunity. The relatively higher price, however, may obstruct some customers' choices.
QSFP+ DAC vs. QSFP+ AOC vs. QSFP+ transceiver, which way to go?
The most effective way to decide is to take transmission distance into consideration. When the transmission distance is under 15 m, using reliable QSFP+ passive copper cable is the most cost-effective solution. When 40G link distance is between 15 m and 100 m, 40G QSFP+ AOC with longer maximum transmission is recommended. If the link distance is longer than 100 m, you can choose 40GBASE-SR4 transceiver working with OM3 over 100 m or OM4 over 150 m, or 40GBASE-LR4 transceiver along with SMF for longer distances of data transmission.
What compatible brands of QSFP 40G transceivers are available from FS?
FS offers cost-effective generic QSFP+ and QSFP+ transceivers compatible with major brands like Cisco, HP, Juniper, Brocade, Dell, Extreme, H3C, Arista, Huawei, Intel, IBM, Netgear, Ciena, D-Link, Avago, F5 Networks, Avaya, Alcatel-Lucent, Aruba Networks, Allied Telesis, SMC Networks, TRENDnet, etc.
Can FS QSFP+ modules and patch cables be shipped directly from North America or Europe?
Yes. FS founded warehouses in North America, Europe, Australia, and Asia. Till now, we have prepared lots of transceiver modules and patch cables in stock. As long as the products you order are all in stock, we will ship them out the same day you place your order from the nearest warehouse.
Can I get a customized 40G optical transceiver according to my needs?
Sure. FS offers regular custom choices such as compatibility, interface type, transmission distance, operating temperature, label pattern, etc. We welcome any inquiry for customized products and solutions for specific requirements.