What Are the Types of 100G QSFP28 Cables?

High-speed data transmission is crucial in today’s data-driven world. As the demand for efficient and fast networking solutions grows, 100G QSFP28 cables have become increasingly popular. These cables come in various types, including Direct Attach Copper (DAC) cables and Active Optical Cables (AOC), offering different benefits and applications. In this blog post, we will discuss the different types of 100G QSFP28 cables, their applications, and why you should consider purchasing optical modules at QSFPTEK.COM.

QSFP28 Cables Introduction

QSFP28 cables are designed to support high-speed data transmission at 100Gbps. They are commonly used in data centers, enterprise networks, and high-performance computing environments. QSFP28 cables are designed to support high-speed data transmission at 100Gbps, ensuring fast and efficient data transfer for various applications. They are commonly used in data centers, enterprise networks, and high-performance computing environments to provide a robust and reliable solution to meet the growing demands of today’s data-driven world.

qsfp28 cable types

There are three main types of 100G QSFP28 cables, each with unique features and benefits, catering to different connectivity requirements:

  1. 100G QSFP28 DAC (Direct Attach Copper) cables: These cables utilize copper as the transmission medium, providing a cost-effective solution for short-range, high-speed connections. DAC cables offer low power consumption, low latency, and are suitable for distances of up to 7 meters. They are ideal for data center interconnects, short-range connections within enterprise networks, and high-performance computing clusters.
  2. 100G QSFP28 AOC (Active Optical Cables): AOC cables employ optical fiber for data transmission, allowing for longer transmission distances compared to DAC cables. They support data rates of up to 100Gbps and can reach distances of up to 100 meters. Active Optical Cables use electrical-to-optical and optical-to-electrical converters, enabling higher flexibility, lower power consumption, and improved signal integrity over longer distances. They are ideal for medium-range connections in data centers, enterprise networks, and other high-speed networking applications where copper cables may not be suitable.
  3. MTP-12 Fiber cables with 100GBASE-SR4: These cables use MTP-12 connectors and multi-mode fiber to support high-speed data transmission over distances of up to 100 meters. The 100GBASE-SR4 standard utilizes parallel optics technology, transmitting data over 4 separate lanes, with each lane supporting 25Gbps. MTP-12 fiber cables with 100GBASE-SR4 are well-suited for data centers, high-performance computing environments, and enterprise networks that require high bandwidth and low latency connections.

When selecting the right 100G QSFP28 cable for your specific needs, it is essential to consider factors such as transmission distance, power consumption, latency, and cost. By understanding the unique features and benefits of each cable type, you can make an informed decision and ensure optimal performance and reliability for your network infrastructure.

Cable TypeMaterialDistanceSpeedApplications
100G QSFP28 DACCopperUp to 7 meters100GbpsData centers, short-range connections
100G QSFP28 AOCOptical fiberUp to 100 meters100GbpsData centers, medium-range connections
MTP-12 Fiber cable with 100GBASE-SR4Optical fiberUp to 100 meters100GbpsData centers, high-performance computing, enterprise networks
QSFP28 Cable parameters

Types of 100G Passive DAC

100G QSFP28 to 100G QSFP28 Passive DAC

The 100G QSFP28 to QSFP28 Passive DAC cable is designed for short-range, high-speed connections between QSFP28-enabled devices. These cables use copper as the transmission medium and support data rates of up to 100Gbps over distances up to 7 meters. They are ideal for cost-effective, low-latency connections in data centers and other networking environments.

100G QSFP28 to 4× 25G SFP28 Passive DAC Cable

The 100G QSFP28 to 4x 25G SFP28 Passive DAC cable is designed for high-speed connections between a single QSFP28 port and four separate SFP28 ports. This cable allows for the efficient use of 100G QSFP28 ports by splitting the bandwidth into four individual 25Gbps connections. These cables are ideal for data center interconnects and other high-speed networking applications where multiple 25G connections are required.

 Types of 100G AOC

100G QSFP28 to 100G QSFP28 AOC

The 100G QSFP28 to QSFP28 AOC cable uses active optical technology to transmit data over longer distances compared to passive DAC cables. These cables support data rates of up to 100Gbps and can reach distances up to 100 meters. AOC cables are ideal for data centers and other applications where medium-range connections with lower power consumption and higher flexibility are required.

100G DAC and 100G AOC Applications

100G DAC and 100G AOC cables are widely used in various applications, including:

  1. Data center interconnects: Both 100G DAC and 100G AOC cables are used to interconnect switches, routers, and servers within data centers, providing high-speed

connections for efficient data transmission.

  1. Enterprise networks: These cables are ideal for upgrading enterprise networks, offering increased bandwidth and faster data transfer rates to meet the growing demands of modern businesses.
  2. High-performance computing (HPC) clusters: In HPC clusters, low latency and high bandwidth are essential. Both 100G DAC and 100G AOC cables provide the high-speed connections required for optimal performance in these environments.
  3. Cloud service providers: 100G DAC and 100G AOC cables can be used to build high-speed connections between data centers and cloud service providers, ensuring efficient and reliable data transfers for cloud-based applications and services.


100G QSFP28 cables, including DAC and AOC cables, offer high-speed data transmission capabilities and cater to a wide range of applications, from data centers to enterprise networks and high-performance computing environments. Choosing the right cable type for your specific needs is crucial to ensure optimal performance and cost-effectiveness. We recommend purchasing optical modules and cables at QSFPTEK.COM, as they offer a wide selection of high-quality, cost-effective solutions, including 100G QSFP28 DAC and AOC cables. QSFPTEK is committed to providing excellent customer service, competitive pricing, and superior quality products, making them the perfect choice for all your optical module and cable needs. Upgrade your network infrastructure with QSFPTEK’s advanced and efficient 100G QSFP28 cables today.

QSFP28 and SFP28 Transceiver Modules – How to Use?

As the demand for higher network speeds and increased data capacity grows, so does the need for transceiver modules that can keep up. Two such modules that have gained significant popularity in recent years are QSFP28 and SFP28. In this blog post, we’ll discuss the different types of these modules, their applications, and how they can be used to boost network performance.

What is a 100G QSFP28 Module?

The QSFP28 (Quad Small Form-factor Pluggable 28) is a high-density, high-speed optical transceiver module designed for 100 Gigabit Ethernet (100GbE) connections. It is an evolution of the QSFP+ standard, offering four times the data rate per channel. With its compact size and low power consumption, QSFP28 is an ideal solution for data center applications, high-performance computing, and 5G front-haul networks.

100G QSFP28 Transceiver

100G QSFP optic module Types

There are several types of 100G-BASE QSFP modules available in the market, each with its own set of specifications and use cases. In this section, we’ll compare the parameters of QSFP28-100G-SR4, QSFP28-100G-LR4, and QSFP28-100G-ER4.

QSFP28-100G-SR4 is designed for short-range connections and is based on the 100GBASE-SR4 standard. It operates over multi-mode fiber (MMF) with a maximum reach of 100 meters using OM4 fiber.

QSFP28-100G-LR4, on the other hand, is designed for long-range connections and is based on the 100GBASE-LR4 standard. It operates over single-mode fiber (SMF) with a maximum reach of 10 kilometers.

QSFP28-100G-ER4 is intended for extended-range connections and is based on the 100GBASE-ER4 standard. It also operates over single-mode fiber (SMF) but has a maximum reach of 40 kilometers.

QSFP28 ModuleStandardFiber TypeMaximum Reach
QSFP28-100G-SR4100GBASE-SR4MMF100m (OM4)
100G Module types

What is an SFP28 Module?

The SFP28 (Small Form-factor Pluggable 28) module is an upgraded version of the SFP+ standard, offering higher data rates of up to 25 Gigabit Ethernet (25GbE). SFP28 maintains the same form factor as its predecessor, allowing for seamless integration into existing SFP+ infrastructures while providing significant improvements in speed and efficiency. This makes SFP28 an attractive choice for data center applications, core to distribution layer connections, and 5G front-haul networks.

25G SFP and 100G QSFP Application: Data Center and 5G Front-Haul

Both QSFP28 and SFP28 modules play critical roles in modern data centers and 5G front-haul networks. QSFP28 modules enable 100G connections, allowing data centers to handle increased traffic and improve overall performance. In addition, QSFP28 can be configured as 100G to 4x25G, providing flexibility in connecting high-speed devices.

SFP28 modules, with their 25G data rate, are perfect for core layer to distribution layer connections, facilitating faster data transfer between network devices. Furthermore, they can be used in QSFP28 to SFP28 breakout applications, enabling seamless integration of 25G and 100G devices.

In 5G front-haul networks, both 100GBASE QSFP and SFP28 modules support the high bandwidth and low latency requirements necessary for 5G applications. The combination of these modules helps operators build flexible, scalable, and efficient networks to meet the ever-growing demand for data.


In conclusion, QSFP28 and SFP28 transceiver modules have become essential components in modern networking infrastructures, especially for data centers and 5G front-haul networks. Their high-speed capabilities, combined with their compatibility with existing systems, make them invaluable tools for addressing the increasing demand for data capacity and faster network speeds. By understanding the different types of QSFP28 and SFP28 modules and their applications, network operators and data center managers can optimize their infrastructures and prepare for the future of connectivity.

SFP vs SFP+ vs QSFP+, what is the difference?

In the world of optical communications, several types of transceiver modules are widely used for different applications. Among them, SFP, SFP+, and QSFP+ are the most common. In this blog post, we will discuss the main differences between these transceiver modules and help you understand their applications better. Let’s dive in!

What is an SFP optic module?

SFP, or Small Form-factor Pluggable, is a compact, hot-pluggable transceiver module used for both telecommunication and data communications applications. It converts electrical signals to optical signals and vice versa, allowing devices such as switches, routers, and servers to connect to fiber optic or copper networking cables. SFP modules are designed to support a variety of data rates and protocols, including Gigabit Ethernet, Fibre Channel, and SONET.

SFP and SFP+, big upgrade

As data transmission demands increased, the need for higher capacity transceivers became evident. SFP+ (Small Form-factor Pluggable Plus) is an upgraded version of the SFP module, offering a significant improvement in data rate capability. While SFP supports data rates up to 4.25 Gbps, SFP+ can handle speeds up to 10 Gbps. This increase in performance makes SFP+ a popular choice for 10 Gigabit Ethernet and 8G Fibre Channel applications.

What is QSFP? QSFP+ transceiver overview

QSFP (Quad Small Form-factor Pluggable) is a high-density, high-performance optical transceiver module that can support data rates of up to 40 Gbps. QSFP+ is an enhanced version of QSFP, providing even higher data rates, up to 100 Gbps. These transceivers are primarily used in high-speed data center and telecommunications applications, where their high data rates and compact size make them an ideal solution.

QSFP+ transceiver

SFP+ vs QSFP+, Parameter comparison

To better understand the differences between SFP+ and QSFP+, let’s compare their key parameters:

Data RateUp to 10 Gbps    Up to 40 Gbps
Transmission DistanceUp to 80 km (depending on the module type)Up to 40 km (depending on the module type)
Form FactorSmaller, single-channelLarger, 4-channel
Connector TypeLC or SCMPO or MTP or LC
Applications10 Gigabit Ethernet, 8G Fibre Channel40G Ethernet, InfiniBand, 100G Ethernet

From the table above, we can see that QSFP+ modules offer significantly higher data rates than SFP+ modules, making them suitable for more demanding applications such as 40G Ethernet and 100G Ethernet. However, SFP+ modules are smaller and more versatile, making them a popular choice for lower-speed applications.

40G to 10G, what is it?

The transition from 10G to 40G networks is becoming increasingly common as businesses look for ways to enhance their network infrastructure and meet the growing demands of data centers and telecommunications. One popular way to achieve this is by using a 40G to 4x10G connection, which allows for seamless integration between access and aggregation layers in the network.

Using a QSFP-40G-SR4 transceiver at the aggregation layer and SFP-10G-SR transceivers at the access layer is a widely adopted method for this type of connection. The QSFP-40G-SR4 module supports 40G data rates and has an MPO/MTP connector, while the SFP-10G-SR module supports 10G data rates and uses an LC connector. To establish the connection, a breakout cable (also known as a fan-out or harness cable) is used, which has one MPO/MTP connector on one end and four LC connectors on the other end.

This configuration enables the QSFP-40G-SR4 module to transmit data to four separate SFP-10G-SR modules simultaneously, essentially breaking down the 40G link into four individual 10G links. This approach is particularly useful when you need to connect access layer devices with lower-speed requirements to high-speed aggregation switches, ensuring smooth data transmission and efficient use of resources.


In conclusion, SFP, SFP+, and QSFP+ are all essential optical transceiver modules that serve different applications based on their capabilities. SFP is widely used for Gigabit Ethernet, while SFP+ is ideal for 10 Gigabit Ethernet and 8G Fibre Channel applications. On the other hand, QSFP+ is perfect for high-speed data center and telecommunications applications that demand high data rates and high-density solutions.

 100G QSFP28 Choose Guide: 100GBASE-SR4 vs 100GBASE-LR4

In today’s ever-growing world of data, high-speed networks are a must. As businesses continue to rely on efficient data centers and networks, there is an increasing demand for faster and more powerful solutions. The 100G QSFP28 transceiver is one such solution that has become increasingly popular, offering the advantages of both QSFP+ and QSFP28 technologies. In this blog post, we will discuss the benefits of upgrading to QSFP28, the most popular QSFP28 module in 2023, and compare the 100G QSFP28 SR4 and 100G QSFP28 LR4 modules.

 QSFP+ Upgrade to QSFP28, What are the Advantages?

The 100G QSFP is an advanced version of the QSFP+ (Quad Small Form-factor Pluggable Plus) transceiver, offering a host of benefits over its predecessor. As we upgrade from QSFP+ to QSFP28, we can see the following advantages:

  1. Higher bandwidth: QSFP supports 100Gbps bandwidth, which is four times the capacity of QSFP+ (40Gbps). This enables faster data transmission and better performance in data centers and other high-speed applications.
  2. Increased port density: QSFP28 modules have the same physical size as QSFP+ modules, making it possible to fit more ports into the same space, leading to higher port density and improved space utilization.
  3. Enhanced energy efficiency: QSFP28 modules consume less power than QSFP+ modules, reducing energy costs and contributing to a greener environment.
  4. Backward compatibility: QSFP28 modules are backward compatible with QSFP+ ports, allowing for a seamless transition when upgrading your network infrastructure.

The Most Popular 100G QSFP Module in 2023

As of 2023, the 100G QSFP28 SR4 (100GBASE-SR4) module has emerged as the most popular QSFP28 transceiver in the market. The 100G QSFP28 SR4 is ideal for short-range, multi-mode fiber connections in data centers and enterprise networks, supporting link lengths of up to 100 meters over OM4 fiber. Its popularity can be attributed to its excellent performance, cost-effectiveness, and widespread compatibility with a variety of network equipment.

100G QSFP28

QSFP28-100G-SR4 vs 100GBASE-LR4, What is the Difference?

When comparing the QSFP28 100G SR4 and 100G LR4 modules, we can find several key differences:

  1. Transmission distance: The 100G QSFP28 SR4 module is designed for short-range applications, with a maximum transmission distance of 100 meters over OM4 fiber. In contrast, the 100G QSFP28 LR4 module supports longer-range connections, with a reach of up to 10 kilometers over single-mode fiber.
  2. Fiber type: The 100G QSFP28 SR4 module uses multi-mode fiber, while the 100G QSFP28 LR4 module employs single-mode fiber.
  3. Cost: The 100G QSFP28 SR4 module is generally more cost-effective than the 100G QSFP28 LR4 module due to its shorter transmission range and lower power consumption.

100GBASE-SR4 Application

The 100G QSFP28 SR4 module is ideally suited for various applications, including:

  1. Data center interconnects: The 100G SR4 module is perfect for high-speed, short-range connections between data center switches, routers, and servers.
  1. Enterprise networks: The QSFP28 SR4 module can be used to upgrade existing enterprise networks, providing faster data transmission and increased capacity to meet growing demands.
  2. High-performance computing (HPC) clusters: The high-speed data transfer capabilities of the 100G QSFP28 SR4 module make it ideal for HPC clusters, where low latency and high bandwidth are crucial.
  3. Cloud service providers: The 100Gbase- SR4 module can be used to build high-speed connections between data centers and cloud service providers, ensuring efficient and reliable data transfers.


In conclusion, the 100G QSFP28 transceiver is an excellent choice for businesses looking to upgrade their network infrastructure to meet the demands of today’s data-intensive world. The 100GBASE-SR4 module, in particular, has emerged as a popular and cost-effective solution for short-range, high-speed connections in various applications, including data centers, enterprise networks, and HPC clusters. If you are considering upgrading your network, we recommend purchasing optical modules at QSFPTEK.COM

Why Do People Still Use Copper SFP Transceivers?


Electric sfp Introduction

In the age of fiber optics and lightning-fast data transfer, it might come as a surprise that copper SFP (Small Form-factor Pluggable) transceivers are still widely used. In this blog post, we will discuss why copper SFPs continue to hold their ground in the networking world, as well as their advantages and disadvantages compared to their optical counterparts. We will also help you understand how to choose the right copper SFP for your needs.

What is Copper SFP?

Copper SFPs are transceiver modules that support data transmission over copper cables, such as Cat5e or Cat6, using RJ45 connectors. They are commonly used in applications where short distances and lower costs are priorities, like data centers and local area networks (LANs). Two popular copper SFP options are SFP-10G-T (10 Gigabit Ethernet) and 1000BASE-T (1 Gigabit Ethernet), while other notable variants include SFP-10G-T-S, SFP-1G-T, and QSFPTEK transceivers.

SFP+ RJ45 copper

How Does the RJ45 SFP Transceiver Work?

An RJ45 SFP transceiver is a hot-swappable module that plugs into the SFP port of a network device, such as a switch or router. The transceiver receives electrical signals from the device and converts them into a format suitable for transmission over copper cables. On the receiving end, another transceiver converts the signals back into electrical form, allowing the data to be interpreted by the receiving device.

These transceivers support various data rates and standards, such as 1000BASE-T (1 Gigabit Ethernet) and 10GBASE-T (10 Gigabit Ethernet), and are compatible with a wide range of network devices. The use of copper cables with RJ45 connectors makes copper SFPs an attractive choice for short-range applications, as they are cost-effective and easy to install.

What is the Difference Between Optic SFP and Copper SFP?

Optical SFPs and copper SFPs both serve the same purpose: to facilitate data transmission between network devices. However, they differ in their underlying technology and the types of cables they use. Here are the main differences between the two:

  1. Transmission Medium: Optical SFPs use fiber optic cables for data transmission, while copper SFPs use copper cables.
  2. Distance: Optical SFPs can transmit data over much longer distances than copper SFPs, often spanning several kilometers, while copper SFPs are limited to shorter distances, typically around 100 meters.
  3. Data Rate: Both types of SFPs support a range of data rates, but optical SFPs generally offer higher speeds than copper SFPs.
  4. Cost: Copper SFPs and their associated cabling are typically less expensive than optical SFPs and fiber optic cables, making them more attractive for short-range applications.
  5. Signal Interference: Copper cables are more susceptible to electromagnetic interference (EMI) and signal degradation compared to fiber optic cables, which can lead to reduced performance over longer distances.

How to Choose Copper SFP and SFP+?

When choosing a copper SFP or SFP+ transceiver, consider the following factors:

  1. Compatibility: Ensure that the transceiver is compatible with your network devices and supports the desired data rate and Ethernet standard.
  2. Distance: Determine the maximum distance between your network devices and choose a copper SFP with a range that meets your requirements. Remember that copper SFPs are best suited for short-range applications.
  3. Data Rate: Select a copper SFP that supports the required data rate,such as 1 Gigabit Ethernet (1000BASE-T) or 10 Gigabit Ethernet (SFP-10G-T).
  1. Cable Type: Choose a copper SFP that is compatible with the type of copper cable you will be using, such as Cat5e or Cat6.
  2. Vendor: Opt for a reputable vendor, like QSFPTEK, that offers high-quality transceivers and provides good customer support.
  3. Budget: Copper SFPs are generally more cost-effective than optical SFPs, but prices can still vary. Consider your budget when selecting a copper SFP, but don’t compromise on quality for the sake of saving a few dollars.
  4. Power Consumption: Copper SFPs typically consume more power than optical SFPs, so factor in power consumption when making your choice.


Copper SFP transceivers continue to be popular due to their cost-effectiveness, ease of installation, and compatibility with a wide range of network devices. When choosing a copper SFP or SFP+, be sure to consider compatibility, distance, data rate, cable type, vendor, budget, and power consumption. By carefully weighing these factors and selecting the right copper SFP for your needs, you can build a reliable and cost-effective network solution that meets your requirements.

QSFP 40G SR BD vs 40GBASE SR4, What’s The Difference

QSFPTEK get 40G transceiver promotion
QSFPTEK get 40G transceiver promotion

QSFP is a hot-pluggable module with fiber optics. The full form of QSFP is Quad Small Form-factor Pluggable. This is the expanded version of the SFP or Small Form-factor Pluggable concept. QSFP uses “Quad” fiber pairs that allow more powerful data transmission.

This transceiver is used for data communication applications. QSFP products support quad small form-factor pluggable with different baud rates, so there is no change in product solution. QSFP is widely used by data centers as it can provide higher bandwidth. There are different types of QSFP  transceivers. SFP 40GBASE-SR BiDi and 40GBASE-SR4 are the most popular among all. You should choose a transceiver according to your network setup. So, today in this article let’s compare QSFP 40G-SR BD and 40GBASE-SR4.

What Is QSFP 40G-SR BD?

QSFP-40G-SR-BD is one of the most well-known QSFP transceivers. QSFP-40G-SR-BD transceiver is a sort of QSFP 40-Gbps bidirectional transceiver. This is a brief distance transceiver that can be utilized a good ways off of 100m and 150m. QSFP-40G-SR-BD transceiver is known as a duplex LC interface. This module is utilized in information correspondence.

There are two 20GB each subsequent sign directs in the QSFP-40G-SR-BD transceiver. Each sign channel is changed over to 2 bidirectional channels of 20Gbps signal channels. These signs are sent over two frequencies.

The QSFP 40 Gbps BiDi transceiver upholds interface lengths of 100 meters and 150 meters, individually, on laser-upgraded OM3 and OM4 multimode fiber.

This sign works on two distinct frequencies, one for sending and one for receiving.



QSFP 40GBASE SR4 is one of the popular short-distance transceivers used widely. To achieve 40G The QSFP 40GBASE- R4 transceiver uses a parallel multimode fiber or MMF link. The lengths of the links are 100m and 150m. This transceiver is commonly used in data centers to interconnect data lanes. These links support OM3 and OM4 fiber. The QSFP 40GBASE SR4 uses Multi-fiber Push-on connectors for optical links support.

The maximum transmission distance of this optical module is 150 meters. It is often used for multimode fiber transmission. It can support signal transduction of about 100 meters of OM3 optical fiber cable and 150 meters of OM4 optical fiber cable. A QSFP 40GBASE SR4 optical module is suitable for short-distance transmission.

The transmission speed of this optical module is 40Gbps. There are four independent transmit and receive optical signal channels, each of which can support 10 Gbps data transmission. Because 40G Ethernet is an important data center technology, 40G optical modules are widely used in fiber-optic networks.

This optical module can arrange multiple lasers in parallel in the direction perpendicular to the substrate, so multiple lasers can be arranged in parallel in the field of parallel optical transmission and parallel optical interconnection. It is very suitable for application and has high-cost performance, so it is used in widely used broadband Ethernet and high-speed data communication networks.

This optical module is mainly used in switches, routers, and host adapter buses. This is especially suitable for high-traffic processing systems. The most common applications for these systems include data centers, network connectivity, and high-performance computing.

40G QSFP transceiver
40G QSFP transceiver


QSFP40G BD vs QSFP 40G SR4, What’s the Difference?

Many people get confused when choosing a 40G transceiver. This is because transceiver standards are typically a combination of letters and numbers. Some standards and models are very similar to each other. Therefore, in this article, I am providing the difference between QSFP 40g sr bd vs QSFP 40gbase sr4.

Working Principle:

In QSFP 40G-SR BD there are two 20G signal channels. Each signal channel is converted to 2 bidirectional channels of 20Gbps signal channels. These signals are transmitted over two wavelengths.

QSFP 40GBASE SR4 has an independent receiver and transmitter.


QSFP 40G-SR BD is a bidirectional module that provides high bandwidth 40G fiber optic link connectivity. It is designed to connect duplex LC interface mode connections by OM3 or OM4 MMF fiber interfaces at 832nm-918nm wavelength.

QSFP 40GBASE SR4 optical module provides high bandwidth 40G fiber optic link connectivity, primarily via a 12-core fiber optic cable with MPO/MTP fiber connectors. You can also connect 4x10G duplex mode connections by connecting 4 fiber branch cable 10G BASE SR optical interfaces.


As a comparison above, you can choose the right QSFP + module for your network. If the link distance is less than 150 meters, the QSFP 40GBASE SR4 transceiver is the best choice. If you need to transmit on duplex multimode fiber, the QSFP 40G SR BD is best because bidirectional connections can be reached via OM3 or OM4 multimode fiber. QSFPTEK offers 40G transceivers, enabling cost-effective, high-density, and low-power 40G Ethernet connectivity solutions for the data centers.


Q. How Many Lengths Does QSFP 40GBASE-SR4 Cover?

A. The QSFP 40GBASE-SR4 Module upholds connect lengths of 100 meters and 150 meters, separately, on laser-streamlined OM3 and OM4 multimode fiber.

It basically empowers high transfer speed 40G optical connections more than 12-fiber equal fiber (MPO) ended with MPO/MTP multifiber female connectors.

Q. How Does QSFP 40 Gbps BiDi Transceiver Work?

A. QSFP 40-Gbps BiDi transceiver consists of two 20 Gbps transmit and receive channels in the 832-918 nanometer wavelength range to support aggregated 40 Gbps links over two-strand multimode fiber connections.


A Brief Introduction of 1000BASE SX


A Brief Introduction of 1000BASE SX

1000BASE-SX is one of the Gigabit Ethernet standards standardized by IEEE 802.3z. 1000BASE-SX uses optical fiber for the communication cable and realizes a transmission speed of 1 Gbps. 1000BASE is a fusion of the technology cultivated in Ethernet so far and the technology migrated from the Fiber Channel. Fiber Channel is originally a serial interface that uses an optical fiber that connects server equipment and storage equipment at high speed, but the part related to data coding/decoding technology and media interface is the 1000BASE module, which uses an optical interface. It is a standard that uses optical fiber as a transmission medium, and there are two types, 1000BASE SX with a transmission distance of up to 550 m and 1000BASE LX with a transmission distance of up to 10 km, depending on the wavelength of light used and the type of optical fiber. So, here let’s get a brief knowledge about 1000base SX.

What Is 1000BASE-SX?

1000BASE-SX is a standard that uses a multi-mode fiber as a short wavelength laser (wavelength 850 nm) for signal transmission. The transmission distance is 550 m (depending on the core diameter of the fiber), and it is often used for backbones in data centers and connections between servers.

1000BASE-SX module
1000BASE-SX module


The structure of an optical fiber consists of two layers, a core through which light is transmitted and a part called a clad around it. There are two types, multimode optical fiber, and single-mode optical fiber, depending on the diameter of the core. Generally, multimode optical fiber has a core diameter of 50 μm and 62.5 μm, and single-mode optical fiber has a core diameter of 9 μm. 

Currently, single-mode optical fiber is the mainstream, but when it was technically difficult to manufacture single-mode optical fiber, multimode optical fiber was widely used. In a multimode optical fiber, since the refractive index of the core changes so as to increase toward the center, a plurality of modes occurs due to the difference in the refractive index. Therefore, it is not suitable for long-distance transmission.

It uses a multi-mode optical fiber and communicates with laser light with a wavelength of 850 nm. The maximum transmission distance is 550m. Because the equipment is inexpensive, it is used for backbone networks in buildings.

1000BASE-SX module
1000BASE-SX module

How It Works:

1000BASE-SX is a fiber-optic Gigabit Ethernet standard for activity over multimode fiber utilizing a close infrared (NIR) light frequency of 770 to 860 nanometers. The standard indicates a distance limit between 220 meters and 550 meters. By and by, with great quality filaments, optics, and terminations, the 1000BASE-SX will for the most part work over significantly longer distances.

This standard is extremely famous for intra-building joins in huge places of business, colocation offices, and transporter nonpartisan Internet trades. SFP 1000BASE-SX works at 850nm frequency and is just utilized for multimode optical fiber with an LC connector. The customary 50-micron multimode optical fiber of 1000BASE-SX SFP is 550 meters high and the 62.5 microns appropriated interface fiber-optic (FDDI) multimode optical fiber is up to 275 meters. Accept EX-SFP-1GE-SX for instance, this SX fiber handset upholds DOM work, and the most extreme distance of SX SFP is 550m.


1000BASE-SX SFP transceivers are compatible with the 1000BASE-SX standard. The medium of the 1000BASE-SX SFP is multimode fiber. Its operating wavelength is 770nm to 860nm. This type of SFP is used to connect devices both in the same cabinet and in different physical locations up to 1 km (3,280 feet) and is widely used in large buildings, colocation facilities, and carrier-neutral Internet exchanges.


Q. What Is 1000BASE-SX?

A. “S for Short wavelength” specifies the fibers and transmitters to use. The fiber should be of the multimode type and have a wavelength between 770 and 860 nm (usually referred to as 850 nanometers). Depending on the diameter of the fiber (50 or 62.5 microns) and the bandwidth per kilometer), the maximum distances can reach 275 to 550 meters.

Q. How Does 1000BASE-SX Work?

A. The optical fiber used by 1000BASE-SX has a wavelength of 850nm, which is separated into 62.5/125m multimode fiber and 50/125m multimode fiber. Among them, the greatest transmission distance utilizing 62.5/125m multimode fiber is 220m, and the most extreme transmission distance utilizing 50/125m multimode fiber is 500m. 1000BASE-SX takes on 8B/10B encoding strategy.

Q. What Is The Maximum Distance 1000Base-SX Cover?

A. The maximum distance supported varies from 220 to 550 meters, depending on the bandwidth and attenuation of the fiber optic cable used. The currently available standard 1000Base-SX NIC is full-duplex and contains LC fiber optic connectors. So 1000BASE-SX SFP supports a maximum length of up to 550m (depending on fiber type) on multimode fiber at Gigabit Ethernet.


1000BaseSX is most generally executed in a switch-switch arrangement. 1000Base-SX is very much popular for associating Ethernet switches, high-speed locations in various wiring storerooms or structures utilizing long cabling runs. QSFPTEK provides cost-effective, high-quality 1G SFP transceivers with a wide selection of 200+ brands compatible with 1000BASE-SX SFP modules. If you still have any questions, please contact sale@qsfptek.com.

What is QSFP28 Top 4 Popular Types and Price Investigation

With the rapid development of data centers, low-rate optical communication products cannot meet the everyday data transmission demand. High-speed 100G QSFP28 transceivers are greatly used by communication service providers today. The article next will introduce you to the four most popular types of QSFP28 modules and show you a QSFP28 price investigation, helping your 100G Ethernet connectivity deployment.

What is QSFP28?

QSFP stands for Quad Small Form-factor Pluggable, and ‘28’ indicates that each lane has a maximum transmission rate of 28Gbps, resulting in a total of approximately 100G data rate with all 4 lanes. QSFP28 evolved from CFP, CFP2, and CFP4. CFP is the first generation of 100G optical transceiver, which features a large size. Subsequently, CFP4 launched, which is a quarter of CFP. And now comes the QSFP28, the latest generation of 100G transceiver modules solution, the form factor of which is smaller than CFP4. QSFP28 has become the most mainstream transceiver solution in 100GbE Ethernet with the significant advantage of high-density.

Four of the Most Popular Types of QSFP28

These are four of the most popular types of QSFP28, QSFP-100G-SR4, QSFP-100G-LR4, QSFP-100G-CWDM4, and QSFP-100G-PSM4. Next, this blog will give an extensive introduction about these four QSFP28 100G transceivers.

QSFP-100G-SR4 Introduction

100GBASE-SR4 QSFP28 transceiver supports a transmission distance of 100m over OM4 and 70m over OM3 with an MTP/MPO-12 connector. The 100GBASE SR4 transceiver carries 100G Ethernet signals with 12 fibers MTP-12 multimode trunk cable. 100GBASE SR4 provides 4 independent full-duplex transmit and receive lanes, each of which supports a 25 Gbit/s data rate, resulting in a total data rate of 100Gbps. In the transmitter of QSFP28 SR4, electric signals are converted into optical signals through a 4 laser array. Subsequently, optical signals are transmitted in parallel over the multi-mode fiber to the receiver. The parallel optical signals revert to parallel electric signals through the 4 PIN array on the receiver side. The working principle of 100GBASE QSFP28 SR4 is shown in figure 1.

Figure 1 — QSFP-100G-SR4 Working Principle

Figure 1 — QSFP-100G-SR4 Working Principle

QSFP-100G-LR4 Introduction

100GBASE-LR4 QSFP28 transceiver supports transmission distance up to 10km over single-mode fiber with duplex LC connectors. The 100GBASE LR4 transceiver enables high-bandwidth 100G optical links over duplex single-mode fiber. Different from 100GBASE SR4, QSFP28 LR4 converts 4 lanes of 25Gbps electric signals into 4 lanes LAN WDM optical signals, then multiplexing them as a single lane with MUX to realize 100Gbps data rate transmission. On the receiver side, instead, the 100G optical signals are demultiplexed as four lanes LAN WDM optical signals with DEMUX and output as four lanes electric signals. The working principle of 100GBASE QSFP28 LR4 is shown in figure 2.

Figure 2 — QSFP-100G-LR4 Working Principle

Figure 2 — QSFP-100G-LR4 Working Principle

QSFP-100G-CWDM4 Introduction

100GBASE-CWDM4 QSFP28 transceiver supports a transmission distance up to 2km over duplex single-mode fiber (SMF) with duplex LC connectors. Based on CWDM technology, QSFP28 CWDM multiplexes four wavelengths of 1270nm、1290nm、1310nm, and 1330nm to a single single-mode fiber to transmit 100Gps data. On the receiver side, instead, the module optically demultiplexes the 100Gbps dates as 4 lanes signals and converts them to 4 lanes of electrical signals. The working principle of 100GBASE QSFP28 CWDM4 is shown in figure 3.

Figure 3 — QSFP-100G-CWDM4 Working Principle

Figure 3 — QSFP-100G-CWDM4 Working Principle

QSFP-100G-PSM4 Introduction

The QSFP-100G-PSM4-S Module supports link lengths of up to 500 meters over SMF with MPO connectors. The 100 Gigabit Ethernet signal is carried over 12-fiber parallel fiber terminated with MPO connectors. The 100GBASE PSM4 transceiver enables four independent full-duplex lanes, each of which transmits data rate up to 25Gbps at the wavelength of 1310nm. It is generally applied in 40G Ethernet and 100G Ethernet. The working principle of 100GBASE QSFP28 PSM4 is shown in figure 4.

Table 1 — QSFP28 100G Transceiver Price Investigation

Figure 4 — QSFP-100G-PSM4 Working Principle

Price Investigation of the 4 Types of QSFP28 100G in 2021

To intuitively understand the cost and market information of the 4 types of QSFP28 100G transceivers, I made a price investigation based on three third-party suppliers in Nov. 2021, as shown in table 1.

Table 1 — QSFP28 100G Transceiver Price Investigation
Table 1 — QSFP28 100G Transceiver Price Investigation


The mentioned above introduced the specification, matching fiber cable, working principle, and the current market price of the four most popular types of QSFP28 100G modules, including QSFP-100G-SR4, QSFP-100G-LR4, QSFP-100G-CWDM4, and QSFP-100G-PSM4. Among the suppliers investigated, QSFPTEK provides the lowest price of all these 4 types of QSFP28. If you’re interested, you are welcome to visit qsfptek.com.

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G.652 Single Mode Fiber vs G.655 Single Mode Fiber

Optical fiber has good performance properties and is designed for high-speed digital data transmission. Currently, in industry and manufacturing, various types and standards of fiber optic cables are used for organizing communications. Each type of cable has its own area of ​​application. The development of these technologies is reflected in the development of data transmission systems. So, today in this article we are going to discuss single-mode fiber and its G.652 and G.655 standards. See this below…

What Is Single-Mode Fiber?

In a single-mode fiber cable, the core diameter does not exceed 10 microns. Here, the probability of

dispersion is much less, and this makes it possible to transmit a signal at a speed of 10 Gb/s over very long distances. However, a single-mode cable and switching equipment for its arrangement are more expensive and require particularly high-quality welding.

The ITU-T G.65x series is a well-known category of single-mode fiber standards that can be further subdivided into G.652, G.653, G.654, G.655, G.656, and G.657, including G.652 and G.655 are two commonly used options. G.652 vs G.655 fiber, what are the differences, and how to make a wise decision.

What is G.652 Single Mode Fiber?

The single-mode type optical fiber is known by the G.652 standard. The latter was developed for the 1.31 µm wavelength range. With this indicator, G.652 fiber has zero chromatic dispersion and attenuation with a minimum value. In G.652 fiber, the diameter of the core itself is about 9 µm, and the diameter of the cladding is 125 ± 2 µm.

G.652 optical fiber is highly reliable and provides data transfer rates up to 10 Gbps. Often such communication lines are used for single-wave and multi-wave transmission when the distance between two points is on average 50 kilometers.

The use of G.652 fiber in communication lines, where data transmission at a speed higher than 10 Gb / s is required, requires more sophisticated equipment, and, consequently, higher financial costs.

What is G.655 Single Mode Fiber?

This fiber is intended for use in backbone fiber-optic lines and global communication networks using DWDM technologies in the wavelength range of 1.55 microns. Fiber – G.655 has a weak, controlled dispersion in the C band (l = 1.53-1.56 microns) and a large diameter of the light-guiding core in comparison with the G.653 type fiber. This reduces the problem of four-wave mixing and non-linear effects and opens up the possibility of using efficient fiber-optic amplifiers.

The above classification of optical fibers according to their main characteristics is given from the point of view of the user. However, it should be borne in mind that manufacturers and suppliers may have their own classification and labeling associated with the peculiarities of production.

Nevertheless, these materials will help you to orient yourself correctly when choosing a fiber optic cable for the construction of new and expansion of existing fiber-optic communication lines.

sigle mode fiber connectivity


What Should be Paid Attention to Before Buying and Deploying an SFP+ Direct Attach Cable (DAC)

With high-speed development and widespread use of generic cabling systems, fiber cables are widely applied in large and medium-sized networks as a high-bandwidth and safe data transmission medium. However, as the high cost of fiber cabling solutions, Direct Attach Cable (DAC) with copper transmission medium still plays an important role in network cabling systems.

What’s SFP+ DAC Cable?

SFP+ DAC (Direct Attach Cable) is also known as SFP+ Twinax copper cable. As its name implies, it takes copper cable as a material, so SFP+ DACs have the advantages of copper cable,  high electrical conductivity,  convenient installation, and cost-effectivity. 

SFP+ DAC has SFP+ form factor modules at either end of the Twinax copper cable that allows 10G network communication between switches and servers, but the modules are different from SFP+ optical transceiver. The SFP+ module connectors on SFP+ DAC don’t have an expensive laser and electronic component, which results in SFP+ DAC as a cost-saving and low consumption alternative solution of SFP+ optical transceivers. Besides, the transmission distance of SFP+ DAC is fixed, which depends on the length of the copper cable between the two ends of SFP+ connectors.

SFP+ Twinax copper cable is designed with very short distance transmission. The typical application scenarios are within racks and across adjacent racks, such as interconnected with top-of-rack switches and servers.

Attention Points of Buying and Deploying SFP+ DAC

Confirm the Compatibility of SFP+ DAC

The price of SFP+ copper cables is generally high offered by the original equipment manufacturers (OEM) and brands, so many communication service providers favored the third-party manufactures which are able to provide the industry-standard compliant SFP+ DAC. When choosing a third-party supplier, compatibility is the first priority that should be paid attention to. 

Then how to assure compatibility from a variety of third-party suppliers? First, you’d better choose the seller who is able to provide professional technical support and tell them your device brand and model number. Then confirm with them if their SFP+ DACs have been tested on your brand devices. It would be better if they could provide a test report. 

QSFPTEK is recommended, as far as we know, QSFPTEK provides timely technical support and their SFP+ direct attach cables are tested strictly before leaving the factory, testing reports are also available.

Passive or Active SFP+ DACs, Which to Choose?

The difference between active DAC and passive DAC is the active DAC structures with signal processing circuitry while the passive doesn’t, so active SFP+ DAC is much more expensive than passive SFP+ DAC. From the perspective of cost and power consumption, 

it is recommended to choose passive DAC within 7m transmission distances, and choose active DAC beyond 7m transmission links.


Calculating the SFP+ DAC Length You Need

For example, when you deploy SFP+ DAC cables in an 84 inch, 45 RU rack, it is estimated that the cable length is about 7 feet (2.1m) from the top of the rack to the bottom, and about 1.5 feet (0.45m) between adjacent ports. If there are 2 Top-of-Rack (ToR) switches and 20 2U SFP+  interface servers, the SFP+ DAC cable length needed approximately is 3m (2.1+2×0.45≈3m). Consequently, the cable length of the SFP+ DAC you need to buy is 3m.

Calculating the SFP+ DAC Length

Pay Attention to the Minimum Bend Radius

To ensure stability and extend the life of the SFP+ DAC cable, the actual bend radius when deploying should be greater than the required standard of SFP+ DAC minimum bend radius. The minimum bend radius is varied with the different wire gauges, as shown in the following table.

Wire Gauges(AWG)

Minimum Bend Radius


1.5 inch (38mm)


1.3 inch (33mm)


1.0 inch (25mm)


0.9 inch (23mm)


The above has explained the notices when buying and deploying SFP+ DAC cables from the aspects of compatibility, length, minimum bend radius, etc. I would love it if it is helpful to you. If you still have confusion about the SFP+ Twinax copper cable or any communication optics like transceivers and AOCs, you are welcome to consult the professional QSFTEK technical team via sales@qsfptek.com. QSFPTEK provides quality and compatible assured DAC cables at the best price.


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