FN-TRAN-QSFP28-BIDI-BCC | Fortinet Compatible 40/100GB Multi-Mode BiDi - 100m (40GBASE-SR-BD / 100GBASE-SR-BD)

Q: Will this work in place of the Fortinet FN-TRAN-QSFP28-BIDI?
A: Yes. This transceiver is a plug-and-play replacement for the FN-TRAN-QSFP28-BIDI. It supports the same 40GBASE-SR-BD and 100GBASE-SR-BD standards, QSFP28 form factor, dual-rate operation, and duplex LC multi-mode fibre interface. It will operate identically in any Fortinet system with QSFP28 slots.

Q: Which Fortinet platforms support this transceiver?
A: This transceiver is designed for Fortinet systems with QSFP28 or QSFP+/QSFP28 slots. It supports both 40G and 100G operation, making it suitable for switches and routers requiring short-reach multi-mode connectivity. Verify your platform datasheet for QSFP28 slot availability and multi-rate support.

Q: How do the Tx and Rx wavelengths work in bidirectional operation?
A: Each LC port simultaneously transmits and receives on different wavelengths. One end transmits at 850nm and receives at 900nm, while the other does the inverse. Passive WDM filters at both transceivers isolate the Tx and Rx channels, enabling full-duplex communication over a single fibre pair. Both transceivers must be BiDi-capable.

Q: What determines the reach difference between 40G and 100G modes?
A: 100G mode uses PAM4 modulation at 50Gb/s per lane, which is more sensitive to dispersion and attenuation than the 20Gb/s NRZ modulation used in 40G mode. This limits 100G reach to 70m on OM3 and 100m on OM4, while 40G achieves 100m on OM3 and 150m on OM4. The same fibre infrastructure supports both rates.

Q: Can this transceiver be used in a 4x25G breakout configuration?
A: No. BiDi transceivers use an internal gearbox to convert 4x25G electrical lanes into 2x50G optical lanes with wavelength multiplexing. The optical architecture does not support per-lane breakout. For 4x25G breakout you would need a 100GBASE-SR4 transceiver with MPO connector and parallel fibre breakout cable.