A BiDi (bidirectional) module transmits and receives on a single fiber strand, using two wavelengths — one in each direction — instead of the usual fiber pair. The engineering consequence is simple and valuable: a plant built with single strands, or a duct with no spare pairs, can carry twice the links. GRT includes BiDi modules in its optical transceiver family for exactly these constrained plants.
BiDi modules are always deployed as matched pairs: the module at one end transmits on wavelength A and receives on B; its partner does the reverse. Ordering therefore happens in pairs, and sparing means stocking both halves. Where fiber is plentiful, conventional duplex modules remain cheaper per link — BiDi earns its premium where strands, not money, are the constraint: leased fiber, legacy single-strand risers, and last-mile access.
Specify BiDi when
- Your duct or lease gives you single strands, not pairs
- A riser is full and pulling new fiber means construction
- You need to double link count on existing single-mode plant
Must BiDi modules be bought in pairs?
Yes. The two ends are complementary (opposite wavelength assignments) and only work as a matched pair.
Does BiDi work over multimode?
BiDi is overwhelmingly a single-mode discipline. Tell us your plant type and distances for a firm recommendation.