Fiber is a valuable resource. Laying new cable is expensive and slow, especially across cities or between buildings. BiDi transceivers help you get more out of the fiber you already have by sending and receiving data over a single strand.
How BiDi works
A standard transceiver uses two fibers: one to transmit and one to receive. A BiDi (bidirectional) transceiver uses Wavelength Division Multiplexing (WDM) to do both over the same fiber. Each end transmits on a different wavelength and receives on the other. For example:
- 1G BiDi: one module transmits at 1310 nm and receives at 1550 nm; the module at the other end does the opposite.
- 10G BiDi: commonly 1270 nm and 1330 nm, again with one wavelength in each direction.
Because the wavelengths don’t interfere with each other, both directions travel through the same fiber at full speed.
Always in pairs
The most important rule: BiDi modules must be installed in matched pairs. One end uses the “upstream” (U) module and the other end uses the “downstream” (D) module, with transmit and receive wavelengths reversed. Installing two identical modules at both ends will not work. Also make sure both modules are rated for the same speed and distance.
Benefits
- Half the fiber: each link uses one strand instead of two, effectively doubling the capacity of your existing cable.
- Lower costs: fewer fibers means smaller cables, fewer splices and fewer patch panel ports.
- Faster growth: you can add new links without installing new cable.
Where BiDi makes the most sense
- ISP backbones and backhaul where fiber is limited or leased.
- Connections between buildings on a campus.
- FTTx networks and links to remote cabinets.
- Any network where existing fiber is running out.
Things to keep in mind
- BiDi modules use a simplex LC connector, so use simplex patch cords.
- They are typically designed for single-mode fiber, with distances of 10, 20, 40 km or more.
- As with any transceiver, they must be coded for your equipment brand to be recognized.
- Label the U and D ends clearly so technicians install them correctly.
Find your BiDi transceivers
Explore our 1G SFP BiDi and 10G SFP+ BiDi modules, compatible with the brand your network requires. Contact us to confirm the right pair for your link.