X520-DA2 does not ship with any optics, if you need only one port. you can go with X520-SR1 or X520-LR1 depending on your switch (SR or LR). sharing a link below for your reference.
http://www.intel.com/support/network/adapter/pro100/sb/CS-030612.htm Intel® Server Adapters — Which SFP+ Modules, SFP Modules, and Cables Can I Use with the X520 Series?
for X520-DA1 OCP (Open Compute Project), it has a different physical form factor compared to X520-DA2. kindly refer to the link below for picture of X520-DA1 OCP.
https://www-ssl.intel.com/content/www/us/en/network-adapters/converged-network-adapters/server-adapt... Intel® Ethernet Server Adapter X520-DA1/X520-DA2 for OCP
hope this help.