Free space optic network

A method performed by a FSO network node, the FSO network node comprising a first receiving module configured to receive a first FSO signal comprising a first set of multiplexed wavelengths, a second receiving module configured to receive a second FSO signal comprising a second set of multiplexed wavelengths, a first wavelength selective device configured to drop a first subset of wavelengths from the first set of multiplexed wavelengths and a second wavelength selective device configured to drop a second subset of wavelengths from the second set of multiplexed wavelengths, the method comprising:

• monitoring the first subset of wavelengths received at the first receiving module;
• monitoring the second subset of wavelengths received at the second receiving module;
• blocking, using the first wavelength selective device, a third subset of wavelengths from the first set of multiplexed wavelengths corresponding to the second subset of wavelengths dropped by the second wavelength selective device;
• and
• blocking, using the second wavelength selective device, a fourth subset of wavelengths from the second set of multiplexed wavelengths corresponding to the first subset of wavelengths dropped by the first wavelength selective device.