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QSFP Optical Module Wiki
Knowledge Base + 2024.01.16

QSFP, full name Quad Small Form-factor Pluggable, four-channel small form-factor pluggable optical module with four independent full-duplex transceiver channels. It was originally designed to replace single-channel SFPs with high-density optical modules, and the QSFP is only 30% larger than a standard SFP module. This device supports rates from 100Mbps to 10Gbps, and like the SFP, it has digital diagnostic capabilities to monitor link performance.The QSFP was developed for high-density applications. The original system design is limited by the number of fibers due to the limited area of the equipment frame panel, and the number of channels that can be accommodated using standard SFP or 10Gbps XFP connectors is mainly limited by physical space.

QSFP was developed in this context to centralize more transponders and receivers in a smaller space. It was Cisco that initially pioneered the development of the QSFP for use in SONET/SDH because typical SONET systems are designed with backplanes based on bandwidth first, and then configured with the appropriate boards. For example, a SONET system with a 10Gbps backplane could be designed with four OC-48 ports, or a board that supports 16 OC-12 ports. Theoretically, this system could support 64-port OC-3 boards. But this is where the problem comes in, the system designer can't make a 64-port line card because there just aren't that many transponders to fit on the front panel.

So the idea of developing this QSFP high-density compact interface for OC-3 ports was born. Since then, several companies have entered into Multi-Source Agreements (MSAs) for the manufacture of QSFPs, and the devices have been gradually upgraded. qSFPs have also moved out of the purely single-mode fiber SONET applications into other multi-mode fiber applications such as Gigabit Ethernet, Fibre Channel, InfiniBand, etc. The MSAs have been in place for many years, and are now available in a number of countries. Many MSA members supply VCSEL chips or parallel VCSEL chips, driving the use of QSFP technology in multimode applications.

QSFP's 4-channel pluggable interface achieves transmission rates of up to 40 Gbps. many of the key technologies matured in XFP are applied to this design. It serves as a fiber optic solution and outperforms the 4-channel CX4 interface in both speed and density. The QSFP can be up to four times as dense as XFP products and three times as dense as SFP+ products because it can support four channels of data transfer at 10Gbps per channel in the same port size as XFP. The QSFP interface with four channels and higher density than CX4 has been adopted by the InfiniBand standard.


Product Features

  • Four-channel bi-directional active fiber optic cable

  • 3.3V power supply

  • Transmission rate: 1Mbps~11.5Gbps

  • Compliant with QSFP MSA standard

  • Utilizes high reliability lasers

  • Transmission distances of 20, 30, 50, 100, 300 meters or longer up to 80KM are available for customization.

  • Hot-swappable

  • Built-in digital diagnostics

  • Low power consumption: less than 0.9 watts per terminal

  • Easy to maintain with electrical interface only

Product Applications

  • 1-10Gbps InfiniBand DDR 4-channel interconnects

  • High performance computers

  • High-end routers and switches

  • Data storage centers


Product DescriptionData Rate (Gbit/s)ReachTXRXPower ConsumptionTemperature (deg C)
QSFP-40G-SR440G100m850nm VCSELPIN<1.5w0~70°C/-40~85°C
QSFP-40G-eSR440G300m850nm VCSELPIN<1.5w0~70°C/-40~85°C
QSFP-40G-IR440G2kmDFB CWDMPIN<3.5w0~70°C/-40~85°C
QSFP-40G-LR440G10kmDFB CWDMPIN<3.5w0~70°C/-40~85°C
QSFP-40G-ER440G30kmDFB CWDMAPD<3.5w0~70°C/-40~85°C
QSFP-40GPSM-IR440G1.4km1310nm FPPIN<3.5w0~70°C/-40~85°C
QSFP-40GPSM-LR440G10km1310nm DFBPIN<3.5w0~70°C/-40~85°C
QSFP-40GAOC-X40G0~300m850nm VCSELPIN<1.5w0~70°C/-40~85°C
QSFP-40G-LX440G150m/2kmDFB CWDMPIN<3.5w0~70°C/-40~85°C全系列

5G Series

QSFP-56G-SR456G100m850nm VCSELPIN<1.5w0~70°C/-40~85°C
QSFP-56G-eSR456G300m850nm VCSELPIN<1.5w0~70°C/-40~85°C
QSFP-56GAOC-X56G0~300m850nm VCSELPIN<1.5w0~70°C/-40~85°C

The QSFP+, or Quad Small Form-factor Pluggable Plus, is based on the QSFP and is a solution designed for high-density applications. The whole system includes 38PIN connectors, EMI shielding components, optical transceivers, heat sinks, copper cable assemblies, MTP fiber optic cable assemblies, optical loopbacks, and so on.

The block diagram is shown below:



 The product family is designed to meet the 40 Gb/s per port bandwidth requirements of the IEEE 802.3ba specification, Infiniband QDR and Fibre Channel requirements. System functionality is defined by the SFF-8436 specification, a protocol that defines the electrical, optical, and mechanical characteristics of the QSFP+, as well as the I2C bus management interface. The hot-swappable transceiver integrates four transmit channels and four receive channels. the QSFP+ transceiver can replace four standard SFP+ transceivers.

The greater port density and overall system cost savings exceed that of traditional SFP+ products. the QSFP+ cable assemblies are designed to be configured for extremely high density requirements. The system will support 10G Ethernet, Fibre Channel, InfiniBand, SAS and SONET/SDH standards using different data rate options. These include InfiniBand Single Data Rate (SDR), Double Data Rate (DDR) and Quad Data Rate (QDR), Ethernet (10~40 gbps), Fibre Channel (8, 10 gbps), and SAS (12 gbps).

The main applications are: switches, routers, host adapter buses; enterprise storage; high-density, high-speed I/O; multi-channel interconnect. The solution is particularly suited to high-traffic processing systems, which are most typically used in data centers, network connectivity, and high-performance computing.

Independently developed by Walsun, the fiber-optic pluggable QSFP+ optical module features high bandwidth, high speed, small form factor, and low power consumption. It integrates four transceiver channels and can replace up to four standard SFP+ transceivers. It offers higher port density and total system cost savings than traditional SFP+ products, and is more flexible, easier to manage and maintain than traditional AOCs. Especially important is the unique COB (Chip-On-Board) design inside the product, which has the advantages of simple structure and low cost, and will show strong competitiveness in the related product field.