BiDi Transceiver: Utilizing WDM Technology for Dual-Direction Data Transmission
Updated at Dec 31st 20241 min read
The demand for advanced optical communication is growing with increased networking. BiDi transceiver, a compact optical transceiver with WDM (wavelength division multiplexing) technology and SFP multi-source protocol (MSA) compliance, allows fast data transmission using a single fiber optic for both sending and receiving signals, saving resources and cutting infrastructure costs. This article discusses BiDi transceivers' functionality, usage scenarios, and benefits to help decide on adopting this technology in your network environment.
How Does BiDi Transceiver Work?
BiDi transceivers, short for Bidirectional Small Form-Factor Pluggable transceivers, operate based on the principle called Wavelength Division Multiplexing (WDM), which simply refers to transmitting information simultaneously in a single communication link, by utilizing two different colors of light. Essentially, what happens is that there are two lasers inside – one sends out light while another collects it back again – doubling the data capacity of this fiber link. Specifically, this is as follows:
There are two sets of devices in the upstream ("U") and downstream ("D") directions, each transmitting at a different wavelength. For example, A transceiver is installed from point A to point B, sending to point B (TX) at 1310nm wavelength, while point B's transceiver receives at 1310nm (RX) and sends back to point A at 1490nm wavelength on the same fiber, and point A listens for 1490nm frequency reception (RX).

Figure 1: The Working Principle of BiDi Transceiver
How Many BiDi Transceiver Types?
BiDi transceivers are available at varying speeds, transmission rates, and wavelengths. The following provides a thorough explanation of the various kinds:
Transceiver Type | Speed | Wavelengths | Distance | Connector | Use Case |
BiDi SFP | 1G | 1310nm/1490nm, 1310nm/1550nm;
1490nm/1550nm | 10km to 40km (short/medium)
80km to 160km (long-haul) | LC Duplex (SMF) | 1G network deployment |
BiDi SFP+ | 10G | 1270nm/1330nm; 1490nm/1550nm | 10km to 60km (short/medium)
80km to 100km (long-haul) | LC Duplex (SMF) | 10G Ethernet deployment |
BiDi XFP X2 | 10G | 1270nm/1330nm; 1490nm/1550nm | 10km to 60km (short/medium)
80km to 100km (long-haul) | LC Duplex (SMF) | Advanced 10G applications |
25G SFP28 BiDi | 25G | 1270nm/1330nm | Up to 40km | LC Duplex (SMF) | 25G Ethernet deployment |
100G QSFP28 BiDi CWDM4 | 100G | 1271nm, 1291nm, 1311nm, 1331nm | Up to 2km | LC Duplex (SMF) | High-speed 100G applications (short-distance) |
40G QSFP+ BiDi | 40G | 850nm | Up to 100m on OM3 MMF
up to 150m on OM4 MMF | LC Duplex (MMF) | 10G to 40G upgrade solution |
The BiDi SFP transceiver is used in today's networks for 1G deployment. 1310nm/1490nm and 1310/1550 nm are the most common wavelength combinations for short/medium-distance (10km to 40km) networks, while 1490nm/1550nm is generally used in long-haul (80km to 160km) BiDi SFP applications. The 1G BiDi variant in GBIC form is also available.
The BiDi SFP+ transceiver is designed for 10 Gigabit Ethernet deployments. 1270nm/1330nm is the most common wavelength combination, which is used in short/medium (10km to 60km) distance transmission whereas 1490nm/1550nm (80km to 100km) is used in long-haul applications. For advanced use, BiDi XFP X2 variants are available for 10G applications.
The 25G SFP28 BiDi transceiver supports connections up to 40km over single-mode fiber and uses LC connectors. The wavelengths are 1270nm/1330nm.
The 100G QSFP28 BiDi CWDM4 transceiver supports connections up to 2km over single-mode fiber and uses LC connectors. The wavelengths are 1271 nm, 1291 nm, 1311 nm, and 1331 nm.
The 40G QSFP+ BiDi transceiver has two 20G channels that support connections up to 100 meters on OM3 MMF and up to 150 meters on OM4 MMF. It uses an LC Duplex connector and the wavelength is 850nm. QSFP+ BiDi is a cost-effective solution for a 10G to 40G upgrade.

Figure 2: The Working Principle of 40G QSFP+ BiDi
The FS BiDi module can provide the above multiple rate configurations and easily adapt to diverse transmission requirements, whether it is a high-bandwidth scenario or a low-latency application. Designed with a focus on ease of use and compatibility, it seamlessly integrates into existing infrastructure and is compatible with a wide range of interface standards, making it ideal for both enterprise networks and individual user deployment.
Why BiDi Transceiver?
This single fiber BiDi transmission gradually becomes a popular and cost-effective solution for today's data center and IT infrastructure because of its unbeatable advantages:
Double Your Network Capacity – One benefit of BiDi is that it allows you to make full use of all your fiber strands and can therefore double your network capacity. This is because one strand is used to carry information in both directions, for example, if you have a six-strand cable you would be able to utilize all six stands rather than three for one direction and three for the other.
Reliability and Efficiency - Bidi wavelength technology optimizes fiber communication by using two separate wavelengths for the transmit and receive channels, effectively alleviating network congestion and significantly improving transmission efficiency. It enables longer distance transmission while still maintaining high signal quality. The simplified single-chain structure reduces the potential connection failure points, reduces the error probability, and meets the dual needs of stability and performance in modern high-speed network environments.
Cost-Saving - BiDi modules eliminate the need for multiple cables and save money by achieving high density data transmission with minimal wiring. Dual-channel operation enables rapid deployment, lowers running expenses, the number of physical ports, and eliminates the requirement for optical fibers. The reduced use of equipment cuts down power consumption, which helps operators save overall energy costs.
Where BiDi Tansceivers Are Used?
BiDi modules are usually deployed in applications like access PON networks deployment P2P (point-to-point) connection, Digital Video, and Closed Circuit Television (CCTV) applications. They can be installed on servers, switches, routers, OADM to provide high speed and stability optical transmission systems, and Metropolitan Area Networks (MAN). In addition, 25/50G BiDi transceivers are welcomed by 5G networks since they can save fiber resources and support high bandwidth, ultra-low latency, and high reliability for data transmissions.
Conclusion
BiDi transceivers are adaptable and effective components utilized in contemporary networks. They cater to diverse speed and distance demands, rendering them perfect for data centers and IT infrastructure, as well as certain high-speed transmission scenarios. FS is committed to providing customers with the best quality and affordable solutions and has a wide range of product lines to choose from in the BiDi transceiver sector. Whether you need standard configuration or special customized requirements, we can provide satisfactory service.
Being a pioneer in network communication, our transceivers' outstanding performance is proven not only by their high-spped and stable data transmission but also by their capacity to maintain high reliability and low latency in the intricate and dynamic network environment, guaranteeing accurate and timely information transfer. Strong compatibility allows our products to readily access a wide range of mainstream network architectures, which considerably saves time and energy when upgrading outdated systems or deploying and implementing new projects. Our dedication to original quality ensures that every product can meet or surpass our customers' expectations.
If you have any questions or would like more details, please feel free to contact us for professional advice and support.