Bidirectional (BiDi) Transceiver Technology, The Most Effective Method to Improve Fiber Utilization

BiDi (Bidirectional) transceiver plays an important role in increasing optical fiber cable utilization based on the characteristics of transmitting and receiving signals over a single strand of fiber. This post will introduce the working principle of  BiDi transceivers, their attention when you use them, and their benefits.

What is Bidirectional (BiDi) Transceiver Technology?

BiDi transceiver also stands for Bi-directional transceiver. Different from the general fiber optic transceiver structured with both Transmission (Tx) port and receive (Rx) port, the BiDi transceiver has only one port. The single simplex port fulfills the transmission and receiver of different wavelengths' optical signals simultaneously. Most notably, BiDi transceivers must be used in pairs. The most important advantage of the BiDi transceiver is saving fiber resources by combining the two transmission fibers into one.

Figure 1 - BiDi Transceiver Connector

The core component of the BiDi transceiver is BOSA ( Bi-Directional Optical Subassembly). BOSA integrates the laser, detector, and WDM filter together, as shown in figure 2. BiDi transceiver consists of BOSA, laser driver, and amplifier. 

Figure 2 - BOSA Structure of BiDi Transceiver

Using Attention of BiDi Transceiver

BiDi transceiver must be used in pairs. For example, if one end uses Tx 1310nm/Rx 1550nm (means transmit signals at a wavelength of 1310nm, and receive signals at a wavelength of 1550nm), the other end should use Tx 1550nm/Rx 1310nm (means transmit signals at a wavelength of 1550nm, and receive signals at a wavelength of 1310nm ).

Common wavelength combinations:

For 1G BiDi SFP, 1310nm/1550nm is generally used in short-distance transmission within 10km. 1310nm/1490nm is used in transmission distance within 40km. 1490nm/1550nm is used in long-haul transmission about 80km to 120km.

For 10G BiDi SFP+, 1270nm/1330nm is used in short/ medium distance within 80km, and 1490nm/1550nm is used in long-haul optical fiber transmission approximately 80km to 100km.

Application and Benefits of BiDi Transceiver

Take a 4G station construction of a certain area for example. The area has 32 3G stations and is without extra fiber resources. In most cases, 4G stations construction is based on previous 3G stations, the advantages of using BiDi transceiver technology is as follows.

BiDi Transceiver is Cost-saving Without Additional Fiber Cables are Required

As the area has no extra optical fiber resources, it will take a long time and difficult to reconstruct fiber. Instead, BiDi transceivers fulfill signals transmission and receiving through a single strand of fiber, so no need for new fiber deployment.

BiDi Transceiver is Easy Deployed

4G station construction is similar to 3G, so the 4G RRU construction is generally based on the current 3G RRU, as shown in figure 3. As the 3G station uses 2-fiber optical fiber between 3G RRU and 3G BBU, when using BiDi technology, the 2-fiber optical fiber resources are entirely utilized, the one fiber carries the previous 3G link, the other fiber carries the new 4G link. The whole operational process is very easy and convenient. 

Figure 3 -  BiDi Transceivers Applied Between RRU and BBU of 3G&4G

BiDi Transceiver is Time-saving When Constructing

As no new optical cable is required, based on the previous fiber link, it only takes about half a month to finish the 32 station construction, which is much shorter than traditional optical transceivers and 2-fiber optical fiber cables construction.

Conclusion

Bidirectional (BiDi) technology is able to improve the utilization of fiber recourse based on current fiber resources, which is considered as the easiest and cost-saving solution to increase network capacity. QSFPTEK offers a large number of 1G BiDi SFP transceivers and 10G BiDi SFP+ transceivers at the best price. Welcome to visit qsfptek.com.