Hello, friend!
Principles for setting the channel spacing (separation band) in a hybrid transmission system (for G.652 fibers and LEAF fibers):
For hybrid transmission of 100G and 40G BPSK services, no guard band is required.
No guard band is required for hybrid transmission of 100G and 40G DQPSK signals.
No guard band is required for hybrid transmission of 40G BPSK and 40G DQPSK signals.
For hybrid transmission of 100G and 10G/40G ODB services, a guard band must be configured and the 100G and 10G/40G ODB services must be adjacent on only one side.
For hybrid transmission of 40G BPSK and 10G/40G ODB services, a guard band must be configured and only single-side neighboring is supported.
Different networks have different requirements on the guard band. The guard band needs to be designed based on the actual scenario.
Thanks!