What does BiDi (Bidirectional) SFP mean and when should I use it?

BiDi (Bidirectional) SFP modules transmit and receive on a single fiber strand using different wavelengths for each direction, effectively doubling fiber capacity.

How BiDi Works

• Uses WDM (Wavelength Division Multiplexing) internally
• One module transmits at wavelength A, receives at wavelength B
• Partner module transmits at B, receives at A
• Common pairs: 1310nm/1550nm, 1490nm/1550nm, 1270nm/1330nm

Deployment: Must Use in Pairs

• Type A (upstream/downstream) always matches Type B
• Two Type A modules will NOT communicate
• Always order in matched pairs

Benefits

• Doubles capacity of existing fiber plant
• Halves fiber costs for new installations
• Reduces splicing and patch panel space
• Same distance capability as regular SFPs

Limitations

• Slightly higher cost per module
• Slightly higher optical loss (WDM filter)
• Must track A/B pairing carefully
• Not all switches auto-detect BiDi type

Use Cases

• Legacy buildings with limited fiber
• Between remote sites where trenching is expensive
• FTTx access networks
• Metro networks conserving fiber pairs

Available Distances

• 3km, 10km, 20km, 40km, 60km, 80km
• Available in 1G, 10G, 25G speeds