Hi @airuntao
Hope you are doing well.
Yes, you use the ethernet interface (eth1) as an optical fiber link. You can set PHY configurations and recheck your correct configurations using ethtool eth1. The ethernet interface only supports MII and RMII. Whenever a PHYter is used for conversion between two different standards, we normally have two sides - the media independent side and the media dependent side.
The media independent side is the link between the processor and the PHYter IC whereas The media dependent side is the one that interfaces the PHYter and the SFP connector.
Thanks and Regards,
Sanket Parekh