Tag Archives: QSFP-40G-LR4

The Basics of 40GBASE-LR4 QSFP+ Transceiver

40GBASE QSFP+ (quad small form factor pluggable) portfolio offers customers a wide variety of high-density and low-power 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, etc. And each kind of 40GBASE QSFP+ transceiver has its special applications. 40GBASE-LR4 QSFP+ transceiver is a common 40 Gigabit Ethernet connectivity option. Here is some basic information about 40GBASE-LR4 QSFP+ transceiver.


40GBASE-LR4 QSFP+ module supports link lengths of up to 10 kilometers over a standard pair of G.652 single-mode fiber with duplex LC connectors. The 40 Gigabit Ethernet signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed within the device. The letter “L” stands for long, the “R” denotes the type of interface with 64B/66B encoding and the numeral 4 indicates numeral 4 indicates that the transmission is carried out over a ribbon fiber with four singlemode fibers in every direction. Each lane has a 10 Gbit/s data rate. 40GBASE-LR4 QSFP+ transceiver modules are compliant with the QSFP+ MSA and IEEE 802.3ba 40GBASE-LR4. The picture below shows a Mellanox MC2210511-LR4 compatible 40GBASE-LR4 QSFP+ transceiver.

Mellanox MC2210511-LR4 Compatible 40GBASE-LR4 QSFP+ Transceiver

Two Types of 40GBASE-LR4 QSFP+ Transceiver

There are mainly two of 40GBASE-LR4 QSFP+ transceivers, 40GBASE-LR4 CWDM (coarse wavelength division multiplexing) QSFP+ transceiver and 40GBASE-LR4 PSM (parallel single-mode fiber) QSFP+ transceiver. This part mainly talks about these two 40GBASE-LR4 QSFP+ transceiver types.

40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, contains a duplex LC connector for the optical interface. It can support transmission distance of up to 10km. A 40GBASE-LR4 CWDM QSFP+ transceiver converts 4 inputs channels of 10G electrical data to 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array, and multiplexes them into a single channel for 40G optical transmission. Then the receiver module accepts the 40G CWDM optical signals input, and demultiplexes it into 4 individual 10G channels with different wavelengths.

40GBASE-LR4 PSM QSFP+ transceiver is a parallel single-mode optical transceiver with an MTP/MPO fiber ribbon connector. It also offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G. The transmitter module accepts electrical input signals compatible with common mode logic (CML) levels. All input data signals are differential and internally terminated. The receiver module converts parallel optical input signals via a photo detector array into parallel electrical output signals. The receiver module outputs electrical signals are also voltage compatible with CML levels.


QSFP-40GE-LR4 supports 40GBASE Ethernet rate only, whereas the QSFP-40G-LR4 supports OTU3 data rate in addition to 40GBASE Ethernet rate. 40GBASE-LR4 QSFP+ transceivers are most commonly deployed between data-center or IXP sites with single mode fiber.

Fiberstore offers customers a wide variety of 40GBASE-LR4 QSFP+ transceivers for your high-density and low-power 40 Gigabit Ethernet connectivity options, including 40GBASE-LR4 CWDM QSFP+ transceiver and 40GBASE-LR4 PSM QSFP+ transceiver, like Cisco QSFP-40GE-LR4 40GBASE-LR4 QSFP+ transceiver. Fiberstore also provides wide brand compatible 40G QSFP+ transceivers, such as Brocade QSFP+, Dell QSFP+, Juniper QSFP+, Mellanox QSFP+, and HP QSFP+. Each fiber optic transceiver provided by Fiberstore has been tested to ensure its compatibility and interoperability. Please rest assured to buy.

Transceiver Choices for 40 Gigabit Ethernet

40GbE (Gigabit Ethernet) is Ethernet standard developed by the IEEE 802.3ba, enabling the transfer of Ethernet frames at speeds of up to 40 gigabits per second (Gbps). Now 40 Gigabit Ethernet is becoming more and more popular, suitable for high-speed, high-demand, and computing applications. For a 40GbE network, transceiver modules are one of the most basic components for transmission, used to plugged into either network servers or various of components such as interface cards and switches. 40GbE transceivers are being developed along several standard form factors. Some basic knowledge of 40GbE transceivers will be provided in the following text.

CFP Transceiver

The CFP (C form-factor pluggable) transceiver features twelve transmit and twelve receive 10Gbps lanes to support one 100GbE port, or up to three 40GbE ports. Its larger size is suitable for the needs of single-mode optics and can easily serve multimode optics or copper as well. The following picture shows a CFP transceiver. 40GBASE CFP transceiver modules are hot-swappable input/output devices that plug into a 40 Gigabit Ethernet CFP port of a switch or router. CFP modules offer customers versatile 40 Gigabit Ethernet connectivity options in core and distribution layers of data center, enterprise, and service provider networks. Main features of 40GBASE CFP modules include:

  • Support for 40GBASE Ethernet and OTU3 standards
  • Support for “pay-as-you-populate” model
  • Support for digital optical monitoring (DOM)
  • Variety of interface choices for 40 Gigabit Ethernet connectivity
  • Interoperability with respective industry IEEE- and/or OTU3-compliant interfaces
  • Support for the Cisco quality identification (ID) feature, which enables a Cisco switch or router to identify whether the module is certified and tested by Cisco
CFP 1310nm 10km Transceiver for SMF
CXP Transceiver

The CXP transceiver form factor also provides twelve lanes in each direction but is much smaller than the CFP and serves the needs of multimode optics and copper. The Roman number X means that each channel has a transmission rate of 10 Gbps. CXP is a kind of hot-pluggable transceiver with data rate up to 12×10 Gbps. It provides twelve 10 Gbit/s links suitable for single 100 Gigabit Ethernet, three 40 Gigabit Ethernet channels, or twelve 10 Gigabit Ethernet channels or a single Infiniband 12× QDR link. The C is the Roman numeral for 100 as a memory aid.

QSFP/QSFP+ Transceiver

The QSFP/QSFP+ (quad small-form-factor pluggable) is similar in size to the CXP and provides four transmit and four receive lanes to support 40GbE applications for multimode and single-mode fiber and copper today. It is the most popular interface of 40G transceivers now. Two main types of QSFP+ transceivers used in the data center are QSFP-40G-SR4 and QSFP-40GE-LR4. The following picture shows an Arista QSFP-40G-SR4 QSFP+ transceiver and a Cisco QSFP-40GE-LR4 QSFP+ transceiver. QSFP-40G-SR4 is used in 4x10G mode along with ribbon to duplex fiber breakout cables for connectivity to four 10GBASE-SR optical interfaces. 40GBASE-LR4 QSFP+ module supports link lengths of up to 10km over a standard pair of G.652 single-mode fibres with duplex LC connectors. In addition, there are other types of QSFP+ modules, such as QSFP-40G-ER4, 40GBASE-PLRL4, etc. Main features of 40GBase QSFP+ modules include:

  • Support for 40GBASE Ethernet
  • Flexibility of interface choice
  • Hot-swappable input/output device that plugs into a 40-Gigabit Ethernet QSFP+ switch port
  • Interoperable with other IEEE-compliant 40GBASE interfaces available in various form factors
  • Support for “pay-as-you-populate” model

Fiberstore offers customers a wide variety of high-density 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, and service provider transport applications. If you have any demand for the 40GbE components or product solutions, please contact Fiberstore team over sales@fs.com or have a livechat on www.fs.com.