Comparison Between Singlemode QSFP28 and Multimode QSFP28

Fiber optic transceiver, as an important optical component, is widely used for transmitting and receiving optical signals to facilitate communication. To meet the increasing demand for higher speed and bandwidth, fiber optic transceiver has continued to evolve, from SFP, 10G SFP+, 40G QSFP+ to 100G CFP and QSFP28. Among them, 100G QSFP28 transceiver is now very popular on the market. We know that fiber optic transceiver can be divided into singlemode transceiver and multimode transceiver, so this article will make a comparison between singlemode QSFP28 and multimode QSFP28.

Singlemode QSFP28

Singlemode QSFP28 is usually used with singlemode fiber. We know that the core of singlemode fiber is smaller and the laser wavelength is narrower. Therefore, singlemode fiber permits the transmission of signals at higher bandwidth thus facilitating the data transmission at a longer distance. Singlemode QSFP28 mainly works at 1310nm wavelength and is commonly used for long distance data transmission. There are different types of singlemode QSFP28 which can achieve different data transmission distance, such as 100GBASE-PSM4 QSFP28 can support 500 meters, 100GBASE-CWDM4 QSFP28 can support 2 kilometers and 100GBASE-LR4 QSFP28 can support 10 kilometers. And there are some other differences among them. The 100GBASE-PSM4 QSFP28 is designed with 12-fiber MTP connector interface, so it is used with MTP cable; while 100GBASE-CWDM4 QSFP28 and 100GBASE-LR4 QSFP28 are structured with duplex LC connector interface, so they are used with duplex LC patch cable.

singlemode QSFP28 and singlemode fiber

Multimode QSFP28

Multimode QSFP28 is usually used with multimode fiber. The core of multimode fiber is much bigger and multimode fiber usually uses a wider wavelength of light. In addition, it permits the use of inexpensive LED light sources and alignment of the connectors with a coupling that is less critical than that of singlemode fiber. As a result, fiber optics used over multimode fiber have a higher capability to gather light from the laser and are cheaper. Multimode QSFP28 mostly works at 850nm wavelength and is used for short optical link length, like 70 meters over OM3 and 100 meters over OM4. There is only one type of multimode QSFP28—100GBASE-SR4 QSFP28. It has 12-fiber MTP connector interface, so it has to be used with MTP cable.

100GBASE-SR4 QSFP28

Comparison Between Singlemode QSFP28 and Multimode QSFP28

From the above, we can clearly see some differences between singlemode QSFP28 and multimode QSFP28. This part will make a summary from several aspects.

Transmission media: Singlemode QSFP28 works with singlemode fiber while multimode QSFP28 works with multimode fiber. It is noted that 100GBASE-PSM4 QSFP28 is used with singleomde MTP cable and 100GBASE-SR4 QSFP28 is used with multimode MTP cable; while 100GBASE-CWDM4 QSFP28 and 100GBASE-LR4 QSFP28 are used with singlemode duplex LC patch cable.

Transmission distance: Singlemode QSFP28 can reach 500 meters, 2 kilometers and 10 kilometers while multimode QSFP28 is able to support 100 meters optical link.

Power consumption: Multimode QSFP28 consumes less power than singlemode QSFP28, which is an important consideration especially when assessing the cost of powering and cooling a data center.

Cost: Singlemode QSFP28 are nearly two or three times higher in price when compared to multimode QSFP28. Because singlemode fiber requires more expensive laser sources and costs more to make as it is more “fragile”.

Compatibility issue: When it comes to issues dealing with compatibility, the two types of QSFP28 transceivers are not compatible due to the differences in fiber core size and wavelengths.

Conclusion

This article makes a comparison between singlemode QSFP28 and multimode QSFP28. Both of them have their own advantages in data center applications. As for which one to choose, it all depends on your specific requirement of deployment. FS.COM, as a professional optical products supplier, offers various QSFP28 optics to meet customers’ diverse needs. If you have any need, please visit www.fs.com for more detailed information.

Cabling Solutions for 100G CFP/120G CXP

The step for higher capacity and throughput in data centers has never stopped and the 100G/120G Ethernet network has been widely applied. However, it is not an easy job to upgrade existing 10G/40G equipment to meet the requirement of 100G/120G Ethernet network. Is there any cabling solution for smooth migration from 10G/40G to 100G/120G? Of course, there is. This article will take multimode 100G CFP/120G CXP transceiver for example and introduce some cabling solutions to you.

100G/120G to 100G/120G

We know that 100G CFP/120G CXP transceiver is designed with 24 fiber MTP/MPO connector interface (10 Tx and 10 Rx with each lane providing 10Gbps, leaving 4 channels unused). Therefore, it is usually used with 24 fiber MTP/MPO cable. The following figure shows that two 100G CFP/120G CXP transceivers are separately plugged into 100G port on two 100G switches. And then the two 100G CFP/120G CXP transceivers can be directly connected by a 24 fiber MTP/MPO trunk cable. This the simplest cabling solution for 100G/120G to 100G/120G connectivity.

100G 120G to 100G 120G

100G/120G to 10G

By using the 24 fiber MPO to 12 LC duplex harness cable, the 100G/120G to 10G connection can be achieved. However, for the optical link completed by 100G CFP transceiver and ten SFP+ transceivers, there are two LC duplex legs are not used; for 120G to 10G connection, one 120G CXP transceiver and twelve 10G SFP+ transceivers are connected which realize 100% fiber utilization. In this cabling solution, three 10G switch may be needed to satisfied the requirement of at least twelve 10G SFP+ ports. As the following figures shows, 100G CFP/120G CXP transceiver is plugged into 100G port on 100G switch on one side, while ten or twelve 10G SFP+ transceivers are plugged into 10G ports on 10G switches on the other side. Then the 100G CFP/120G CXP transceiver and ten or twelve 10G SFP+ transceivers can be connected by the 24 fiber MPO to 12 LC duplex harness cable. This is also the simplest cabling solution for 100G/120G to 10G connectivity.

100G 120G to 10G

With the use of MTP/MPO fiber optic patch panel, 100G to 10G connection can also be reachable. From the figure below we can see that one end of 24 fiber MTP/MPO trunk cable is plugged into 100G CFP transceiver on the 100G switch, while the other end is plugged into MTP ports on the rear of the MTP/MPO fiber optic patch panel. Then the one end of ten LC duplex patch cables are plugged into the LC ports on the front of the MTP/MPO fiber optic patch panel and the other end of cables are connected with ten 10G SFP+ transceivers which are plugged into 10G ports on 10G switches. This cabling solution offers ultimate flexibility in allowing connectivity to any row, rack or shelf. In addition, the MTP/MPO fiber optic patch panel can support up to eight groups of this 100G to 10x10G transmission.

100G to 10G

There is a hybrid link for 120G CXP transceiver, 40G QSFP+ transceiver and 10G SFP+ transceiver. We can use the 1×3 MTP/MPO conversion harness cable to connect 120G CXP transceiver on 100G switch and three 40G QSFP+ transceivers on 40G switches. Then another three 40G QSFP+ transceivers on the 40G switches can be connected with the twelve 10G SFP+ transceivers on 10G switches by three 12fiber MTP-LC fanout cables.

120G to 40G to 10G

Conclusion

As 100G/120G Ethernet network has becomes more and more popular, various types of 100G CFP/120G CXP transceivers are available on the market. This article has illustrated some cabling solutions for migration from 10G/40G to 100G/120G and it is not difficult to find that MTP components are commonly used in these cabling solutions. I hope after reading this article, you can learn something useful.

A Closer Look at 40G QSFP+ SR4 Transceiver

As 40G network has been widely applied in today’s data center cabling system, 40G QSFP+ transceivers gain great popularity among data center managers. And for short data transmission distance, 40G QSFP+ SR4 transceiver is preferred. This article is going to focus on 40G QSFP+ SR4 transceiver and share several cabling solutions for 40G QSFP+ SR4 with you.

Overview of 40G QSFP+ SR4 Transceiver

40G QSFP+ SR4 transceiver is a parallel fiber optic transceiver which means it uses four fibers for transmitting and four fibers for receiving at the same time. Designed with MTP/MPO interface, 40G QSFP+ SR4 transceiver is used together with multimode fiber, such as OM3 and OM4. Working on wavelength of 850 nm, 40G QSFP+ SR4 transceiver can support 40G fiber optic transmission with the link length up to 100 meters over OM3 fiber and 150 meters over OM4 fiber. For application, 40G QSFP+ SR4 transceiver can be used for 10G to 40G and 40G to 40G connections. Here is a figure of 40G QSFP+ SR4 transceiver for you.

40G QSFP+ SR4 transceiver

10G to 40G Connection

Since 40G QSFP+ SR4 transceiver uses four independent full-duplex transmit and receiver channels, the 40G optical signal can be split into four 10G optic signals. Therefore, we can increase the fiber count at the 10G distribution end to realize 10G to 40G connection. As the following figure shows, we can use 12f MPO trunk cable and fiber enclosure. Four 10G SFP+ SR transceivers are inserted into 10G ports on one side, while one 40G QSFP+ SR4 transceiver is inserted into 40G port on the other side. Then the four 10G SFP+ SR transceivers are connected with four duplex LC patch cables which are plugged into LC ports on the front side of MPO fiber cassette inside the fiber enclosure, and the 40G QSFP+ SR4 transceiver is connected with 12f MPO trunk cable which is plugged into MTP/MPO port on the rear of MPO fiber cassette. Finally, the whole optical link is completed.

40G QSFP+ SR4 transceiver for 10G to 40G connectionA

We can also use MPO to LC fanout and MTP fiber patch enclosure which includes MTP fiber adapter panels. This cabling solution is similar to the previous one, but the difference is that the four 10G SFP+ SR transceivers are connected with MPO to LC fanout which is plugged into MTP/MPO port on the MTP fiber patch enclosure. The scenario is shown in the following figure.

40G QSFP+ SR4 transceiver for 10G to 40G connectionB

40G to 40G Connection

The following figure shows the simplest scenario for 40G to 40G connection. Two 40G QSFP+ SR4 transceivers are separately inserted into two 40G switches. Then the two 40G QSFP+ SR4 transceivers are connected by 12f MPO trunk cable.

40G QSFP+ SR4 transceiver for 40G to 40G connectionA

We can also use MTP fiber patch enclosure to achieve better cable management and higher density cabling. The scenario is shown in the following figure. With the use of MTP fiber enclosure, cable management for 40G to 40G connection could be easier. A 48-port 1U rack mount MTP fiber patch enclosure includes up to four 12-port MTP fiber adapter panels with MPO MTP fiber optical adapters on it, here is a figure for you.

40G QSFP+ SR4 transceiver for 40G to 40G connectionB

Conclusion

Designed with parallel transmission mode, 40G QSFP+ SR4 transceiver has a wide range of cabling applications with great flexibility. The cabling solutions mentioned above are just several commonly used ones. As for detailed cabling solutions for 40QSFP+ SR4 transceiver, it is suggested to depend on the practical applications and cabling environments. I hope after reading this article, you can learn more about 40G QSFP+ SR4 transceiver.

Overview of 100G Transceivers

There was a time when 10G to 40G migration was a hot spot, and as the only available 40G transceiver, 40G QSFP+ has occupied the major position in the market. However, the pace of development has never stopped and the demand for higher speed data transmission keeps growing. And now, many data center managers set their sight on 100G Ethernet. As an important component in 100G optical links, 100G transceivers gradually gain great popularity among data center managers. But unlike 40G transceiver, 100G transceiver has several types, such as CFP/CFP2/CFP4, CXP and QSFP28. How much do you know about them? This article is going to give an overview of 100G transceivers.

CFP/CFP2/CFP4

The letter “C” in CFP/CFP2/CFP4 stands for 100. The CFP transceiver is specified by MSA between competing manufacturers and it can support 100Gbps over both single-mode and multimode fiber. The electrical connection of a CFP uses 10 x 10G lanes in each direction (RX, TX) while the optical connection can support both 10 x 10G and 4 x 25G variants of 100G interconnects. With improvement in higher performance and higher density, CFP2 and CFP4 appeared. While electrical similar, they specify a form factor of 1/2 and 1/4 respectively in size of CFP. CFP, CFP2 and CFP4 modules are not interchangeable, but would be inter-operable at the optical interface with appropriate connectors.

CFP-CFP2-CFP4

Here is a table for you which shows five typical transceiver types. We can get that CFP-SR10-100G is structured with 24-fiber MTP connector interface, so it can be used with multimode MTP 24 to MTP 24 100g trunk cable to support 100G optical links over short distance; designed with LC duplex interface, CFP-LR4-100G, CFP-ER4-100G, CFP2-LR4-100G and CFP4-LR4-100G are used with LC duplex patch cable to support 100Gbps data rate over long distance.

CFP CFP2 CFP4 transceiver information

CXP

The CXP was created to satisfy the high-density requirements of the data center, targeting parallel interconnections for 12x QDR InfiniBand (120G), 100G, and proprietary links between systems collocated in the same facility. The CXP is 45 mm in length and 27 mm in width, making it slightly larger than an XFP. It includes 12 transmit and 12 receive channels in its compact package. This is achieved via a connector configuration similar to that of the CFP.

QSFP28

Similar to 40G QSFP+, 100G QSFP28 also offers four independent transmit and receiver channels, but each channel is capable of 25Gbps data rate for an aggregate data rate for 100Gbps. With an upgraded electrical interface to support signaling up to 25Gbps signals, the 100G QSFP28 makes it as easy to deploy 100G network as 10G networks. When compared to any of the other alternatives, the 100G QSFP28 increases density and decreases power and price per bit, but It has to noted that 100G QSFP28 has the same physical size as 40G QSFP+. Just like 40G QSFP+, 100G QSFP28 can be both deployed for short data transmission distance over multimode fiber and long data transmission distance over single mode fiber. For example, 100GBASE-PSM4 QSFP28 can be used with MTP single mode cable to support 100G data rate with link length up to 500 meters.

100G QSFP28 transceiveres

Conclusion

Now is the time of 100G Ethernet and 100G transceivers are indispensable to complete the 100G optical links. As there are various types of 100G transceivers available on the market, it is necessary to choose the best suitable one for your network deployment. As a professional manufacturer and supplier in optical communication industry, FS.COM provides a complete range of 100G transceivers to meet the potential requirements. The prices of all our 100G transceivers are much more affordable than the similar products in the market. Furthermore, with the mature coding technology, they can be compatible with many major brands. For more details, please visit our site.

Difference Between 40G QSFP+ Transceiver with LC Interface and MTP/MPO Interface

Data transmission with higher density and bandwidth has become the trend under present networking environment. With 40 Gigabit Ethernet commonly deployed in most data centers, various network devices designed for 40 Gigabit Ethernet (GbE) link are available on the market. Among them, 40G QSFP+ transceivers play an important role in driving the bandwidth to a mounting point. There are mainly two interfaces adopted by 40G QSFP+ transceivers—MTP/MPO and LC. What is the difference between these two interface types? This article will have an analysis of the 40G QSFP+ transceivers with LC interface and 40G QSFP+ transceivers with MTP/MPO interface.

40G QSFP+ transceiver with MTP and LC interface

40G QSFP+ Transceivers With LC Interface

From the figure below, we can easily understand the working principle of 40G QSFP+ transceivers with LC interface. In the transmit side, 4 channels of 10G serial data streams at different wavelengths are passed to laser drivers. The laser drivers control directly modulated lasers (DML) with wavelengths. Then the output of the four DMLs are optically multiplexed to a SMF through an industry-standard LC connector, combining as 40G optical signal. In the receive side, the 40G optical signal is demultiplexed into four individual 10G optical data streams at different wavelength. And each wavelength light is collected by a discrete photo diode and amplified by a TIA, and then outputted as electric data. In this process, a 4-wavelength CWDM multiplexer and demultiplexer is used over a pair of single-mode fibers. For transmission distance of this type of 40G QSFP+ transceiver, take 40G LR4 QSFP+ transceiver as an example, it can support an optical link length up to 10 kilometers over the single mode fiber.

40G QSFP+ transceiver LC interface working principle

40G QSFP+ Transceivers With MTP/MPO Interface

We can easily understand the working principle of 40G QSFP+ transceiver with MTP/MPO interface from the figure below. In the transmit side, the transmitter converts parallel electrical input signals into parallel optical signals through the use of a laser array. Then the parallel optical signals are transmitted parallelly through the multimode fiber ribbon terminated with MPO/MTP fiber optic connector. In the receive side, the receiver converts parallel optical input signals via a photo detector array into parallel electrical output signals. Generally, 40G QSFP+ transceivers with MTP/MPO interface are utilized for short distance transmission over multimode fiber (MMF), like 40G SR4 QSFP+ transceiver, it can support a link length up to 100 meters on OM3 cable and 150 meters on OM4 cable.

40G QSFP+ transceiver with MTP MPO interface working principle

Note: there are also some 40G QSFP+ transceivers with MTP/MPO interface supporting long distance transmission over SMF. For example, 40G LR4 PSM QSFP+ transceiver, a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector, it offers four independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G over SMF. That is to say, eight single-mode fibers are used to achieve parallel transmission, with transmission distance up to 10 kilometers. From the perspective of cost, this kind of 40G QSFP+ transceivers cost more than 40G QSFP+ transceivers with LC interface. Besides, in the data center fiber infrastructure, MTP patch panel has to be used to accommodate MTP cables, which would cost more than LC connectors and regular SMF cables.

4x10G Connectivity

For the 40G QSFP+ transceivers with LC interface, they cannot be split into 4x10G as they use 4 wavelengths on a pair of single-mode fibers and do not lend themselves to “splitting” into 4 pairs without substantial complexity to split out the wavelengths. For the 40G QSFP+ transceivers with MTP/MPO interface, they can be used in 4x10G connectivity via an external 12-fiber parallel to 2-fiber duplex breakout cable, which connects the 40G module to four 10G optical interfaces.

Conclusion

Generally speaking, the 40G QSFP+ transceivers with LC interface are used for long distance transmission over single-mode fiber (SMF), and 40G QSFP+ transceivers with MTP/MPO interface are utilized for short distance transmission over multimode fiber (MMF). However, for some 40G QSFP+ transceivers with MTP/MPO interface, such as 40GBASE-LR4 PSM QSFP+ transceiver, it can support long distance transmission over SMF. Besides the examples discussed above, there are some other types of 40G QSFP+ transceivers provided by FS.COM, such as 40GBASE-CSR4 QSFP+, 40GBASE-PLR4 QSFP+, 40GBASE-ER4 QSFP+ and so on. If you want to know more details, please visit our site.