There are two possible options to connect the fiber between the GT Readout Platform digital board (on the left) and the PCIe card (on the right):
Direction connection:
This will connect all fibers in order from lane 0 to lane 11
The PCIe card can only connect to 4+4=8 lanes
The last step in the connection to the PCIe card allows to swap the lanes in groups of 4 if needed
LC breakout connection:
This will breakout all 24 individual fibers into a LC adapter panel
The connection shown in the diagram below is a direct one-to-one, but the adapter panel allows for full flexibility in swapping channels and moving them around
It also makes it possible to "inject" e.g. a timing fiber on one of the fiber lanes going to the GT Readout Platform