The demand for more bandwidth, capacity, and performance in the network continues to grow at a rapid pace. As a result, network service providers' migration from 10G to 40G has become an important and unavoidable option.

Optical transceivers enable fiber-to-the-premises (FTTP) services, in which optical fiber is installed from the service provider to the end customer. Placing fiber at the customer's end allows for an extremely fast internet connection. The greater data transfer rate of optical technology is its main advantage.

The given fiber optic cable must be terminated into an end device to use FTTP services. Let that end device be a cable provider's set-top box (STP) for home consumers or any switch, router, or other active devices in an optical network.

As previously stated, an optical transceiver must be installed in the active last mile device at the customer's end, where fiber is to be terminated. An optical transceiver uses light to transmit and receive data.

Optical transceivers come in a variety of shapes and sizes, and the right one for the job will depend on the application, data rate, and services required.
Optical transceivers such as SFP, SFP+, XENPAK, QSFP, and CFP are among the optical transceivers. The working properties of these optical transceivers are strictly controlled by MSA, allowing MSA-compliant optical transceivers to perform reliably across several suppliers.

The details of compatible optical transceivers defined by MSA are listed below.


Compact form-factor pluggable (SFP) is a term that describes a pluggable device with a small form factor. It's a small, hot-pluggable transceiver that can be utilized in both telecommunications and data applications.

• SFP+

SFP+ is an improved version of SFP that enables more than 10 gigabits per second. SFP+ is becoming increasingly prevalent on 10-gigabit ethernet. The enhanced small form-factor pluggable (SFP+) is the same size as a standard SFP, but it can handle data rates up to 16 gigabits per second.


Since XENPAK is also a suitable optical transceiver, a multi-source agreement (MSA) that defines a fiber-optic transceiver module that adheres to the 10 Gigabit Ethernet standard has been established. For fiber, transmission distances range from 100 meters to 80 kilometers. More compact optical transceivers have replaced XENPAK, enabling the same capability.


The C form-factor pluggable (CFP) is a multi-source agreement to provide a standard form factor for the transmission of digital signals with higher bandwidth. Because this standard was primarily created for 100 Gigabit Ethernet, the C is derived from the Latin letter C, which is used to signify the number 100 (centum).


The Quad Small Form-factor Pluggable (QSFP) is a data communications optical transceiver that is hot-pluggable and small. A multi-source agreement specifies the electrical interface and mechanical dimensions of QSFP (MSA).

It's an industry standard that's been agreed upon and endorsed by a number of network component manufacturers, providing data rates of up to 4x10 gigabits per second. The format definition is improving to allow for larger data rates - the maximum rate feasible is 4x28 gigabits per second (also known as QSFP28).

In this post, we'll see why the QSFP-40G-SR-BD is a good alternative for 40G Ethernet.

Overview of the QSFP-40G-SR-BD Transceiver

The QSFP-40G-SR-BD transceiver is a standard QSFP+, MSA-compliant optical transceiver that is a form of QSFP 40-Gbps BiDi transceiver. It includes a duplex LC interface and can work at wavelengths ranging from 832 to 918 nm.

Furthermore, the QSFP-40G-SR-BD transceiver enables transmission distances of 100 and 150 meters over a laser-optimized OM3 or OM4 multimode fiber, respectively (MMF). As a result, this module is frequently utilized for data exchange over short distances.

The QSFP-40G-SR-BD Transceiver's Operating Principle

BOSA (Bidirectional Optical Sub-Assembly) technology permits components to simultaneously transmit and receive optical signals. The QSFP-40G-SR-BD transceiver can carry 40Gbps data over typical 10G MMF cabling by providing two distinct wavelengths on each fiber.

Four 10Gbps signal channels in the QSFP-40G-SR-BD transceiver are transformed into two bidirectional 20Gbps signal channels. Two separate wavelengths are used to carry each 20Gbps signal (usually 850nm and 900nm).


• Low-cost QSFP-40G-SR-BD transceiver for Cisco QSFP-40G-SR-BD 40GBASE-SR BiDi LC Duplex Module.
• Compliant with IEEE 802.3ba-2010's 40GbE XLPPI electrical standard
• QSFP+ SFF-8436 Specification Compliant
• A total bandwidth of 40 Gigabits per second
• With 64b/66b encoded data, it runs at 10.3125 Gbps per electrical channel.
• MSA-compliant QSFP
• Uses standard LC duplex fiber cable, allowing existing cable infrastructure to be reused.
• On OM3 Multimode Fiber (MMF), the maximum connection length is 100 meters, while on OM4 MMF, it is 150 meters.
• Powered by a single +3.3V source
• Digital Diagnostic Monitoring in Real-Time
• Operating temperature range: 0 to 70 degrees Celsius
• Lead-free and RoHS compliant

SFP-40G-SR-BD 40G Transceiver Benefits

1. Easier for upgrading to 40G

It's easier to save current 10G fiber infrastructure for higher-speed 40G cable connections using the QSFP-40G-SR-BD transceiver. You won't need to upgrade your data center's cabling or rewire it for increased capacity.

2. Cost-saving

If you build a 40G data center fabric the old way, you may require a lot more fibers. For example, the 40GBASE-SR4 transceiver needs eight fibers for 40G Ethernet. The QSFP-40G-SR-BD transceiver, on the other hand, only requires two fibers to achieve the 40GBASE-SR4 performance requirements. There is no need to add more fibers when using a QSFP-40G-SR-BD transceiver.

3. Time-saving

As previously stated, 10G Ethernet is insufficiently fast to meet the network's performance demands. You may get a 40G Ethernet with the QSFP-40G-SR-BD 40G transceiver, which is quicker than before. You can save more time in the network to get what you require.


The QSFP-40G-SR-BD 40G Transceiver is an excellent and practical choice for upgrading from 10G to 40G Ethernet. It is not essential to update the fiber infrastructure with high-cost money and time when using the QSFP-40G-SR-BD 40G transceiver.
A reputable supplier can provide you with a variety of 40G QSFP BD transceivers at a low cost and high quality. If you have any needs, welcome to visit  Cisco Optics Modules