The link is a single strand of
fiber, with a different infrared laser wavelength going in each direction.
A splitter prism inside each transceiver separates the two wavelengths;
|To network (Up)||From network (Down)|
|IEEE 802.3||IEEE 802.3|
|TX: 1310 nm||TX: 1490 nm|
|RX: 1490 nm||RX: 1310 nm|
In theory, any fiber media converter which meets the above specs should work.
At my place, a ZTE ZXHN F3100 media converter is installed (powered by a 12V,
1A DC adapter);
Some media converters require a separate
form-factor pluggable transceiver (SFP), which plugs into the media
You may need a LC to SC adaptor plus a LC to LC cord in order to connect to a SFP.
Some routers have SFP slots.