Please recommend if there are any reference design of a USB bridge design that can connect 2 USB 3.0 host controller?
Communication: USB3.0 (SS)
You can connect 2 FX3 back to back, one acting as the GPIF II master and other acting as GPIF II slave. The USB interface of the two FX3 can be connected to two different computers and thus can act as USB3.0 host to host cable.
For example firmware please refer the following application note :