Intel allow_unsupported_sfp
If you would like to use 3rd party optical module in Intel X500 or X700 series PCI cards, then you would need to issue Intel allow_unsupported_sfp=1 configuration parameter. Without this command, there is high chance that 3rd party optical modules will not be recognized and links will not be established.
In FreeBSD, in /boot/loader.conf.local put:
hw.ixgbe.unsupported_sfp=1
In Linux, in /etc/modprobe.d/ixgbe.conf put:
options ixgbe allow_unsupported_sfp=1
Windows has similar option in the driver properties screen.