MikroTik SFP CWDM module 1.25G SM 40km 1610nm LC-connector DDM

Coarse Wavelength-Division Multiplexing (CWDM) technology offers a solution which will increase the capacity of existing fibre infrastructure by enabling multiple channels/wavelengths over the same fibre cabling.
CWDM in your network will allow you to:

Increase efficiency of existing fibre network
Provide scalable and easy-to-deploy fibre channel services
Reduce electricity consumption
Reduce equipment maintenance and installation costs