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What is The Difference Between BIDI And SFP

BIDI and SFP are two commonly used transceivers in optical fiber communications. Choosing the right transceiver is crucial for performance optimization and efficiency and helps control costs. In this article, I’ll walk you through the differences between these two technologies in detail so you can find the one that’s right for you.

What is BIDI

BIDI is a bidirectional transmission transceiver that transmits signals in both directions using a port and an optical fiber. It is performed using a pair of frequencies, such as F1 and F2, on one fiber. Its wavelength is usually 1310nm/1490nm, 1310nm/1550nm, and 1490nm/1550nm. Its F1 is used to send signals, and F2 is used to receive signals. So when using the BIDI module, its Tx end transmits the 1310nm signal to point B through a single optical fiber, and the wavelength of the Rx end at point B must be 1310nm. At the same time, the wavelength of the Tx end of the other module must be 1490nm, corresponding to the 1490nm receiving end of the previous module because BIDI modules must be used in pairs.

What is SFP

The SFP transceiver is a small, compact, and hot-swappable transceiver, which is mostly used for data communications. Different from BIDI, it transmits data through dual ports and dual fibers, one optical fiber is used for the transmission port and the other is used for the receiving port. Its form factor and electrical interface are specified by the Multi-Source Agreement (MSA) supported by the SFF Council and endorsed by numerous network component vendors. Because it uses dual fibers for transmission, the same frequency can be used to transmit and receive signals on both fibers.

BIDI vs SFP, What is The Different

Ports

The BIDI optical module only has one port, through which it transmits signals in two bands at the same time, to achieve the effect that the signals do not affect each other and can be transmitted simultaneously. The SFP optical module has two ports. It uses the same band to transmit on two optical fibers to achieve the purpose of non-influence between the bands.

Optical Fiber

BIDI only uses one optical fiber to achieve bidirectional communication, thus optimizing fiber utilization. SFP transceivers usually require the use of two optical fibers, one for data transmission and one for data reception.

Wavelength

For the BIDI transceiver, since it receives and sends signals in the same optical fiber, the wavelengths of its transmitting and receiving ends need to be different to avoid affecting the signal, and BIDI transceivers must be used in pairs. For example, if we use a 1310nm/1550nm BIDI module at the A end, we must use a 1550nm/1310nm BIDI module at the corresponding other end. SFP does not need to consider so much. Since it transmits signals on two optical fibers and has corresponding receiving ends and transmitting ends, there is no need to use them in pairs.

Application

SFP is usually used in application scenarios where fiber resources are not limited, such as telecommunications and carrier networks. Ensure high-speed data transmission by using SFP modules to connect multiple access points and core nodes. SFP modules are also suitable for mixing and matching multiple different brands of equipment because of their wide compatibility and flexibility. The BIDI module is suitable for scenarios where fiber resources are limited or high-density connections are required. For example, FTTH or high-density data centers require only a single optical fiber to transmit and receive data, so it can also significantly reduce unlimited costs and wiring complexity.

BIDI and SFP, How to Choose

When you are considering how to choose between BIDI and SFP transceivers, you may wish to consider your network needs first. Both SFP and BIDI have their advantages. The following are the factors you need to consider before choosing:

Bandwidth Requirements

You can choose to deploy SFP transceivers when there is high bandwidth demand and network stability requirements. Compared with BIDI transceivers, its technology is more mature, and because two optical fibers are used for signal transmission, the signal paths are separated, reducing the risk of interference and conflict. BIDI, on the other hand, performs two-way signal transmission on a single optical fiber. It has higher requirements for optical fiber, and defects in the optical fiber can easily affect the transmission and reception of signals.

Fiber Optic Resources and Infrastructure

If your network has abundant optical fiber resources and complete infrastructure, choosing SFP transceivers can seamlessly connect with your existing equipment. BIDI is suitable for when your network fiber resources are limited and network upgrades are needed. It can transmit through a single fiber to help you control costs.

Broad Compatibility

Network equipment suppliers widely use SFP transceivers. They have broad compatibility with various network equipment and can be flexibly used with various equipment. BIDI is more suitable for specific deployment scenarios that optimize existing fiber resources.

Conclusion

How to choose between BIDI and SFP transceivers mainly depends on your specific needs for the network. If you prefer compatibility and stability, then SFP transceivers are undoubtedly the best choice. If you want to optimize existing fiber optic cabling for high-density deployment, BIDI transceivers are more suitable. Although BIDI transceivers cost more than SFP transceivers, they require fewer resources for cabling in the long run, helping you control costs. If you have any questions about BIDI and SFP transceivers, please feel free to contact us.

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