Optical add/drop device and assembly, and communications network node

An optical add/drop device comprising:

• a common port;
• an add port;
• a first wavelength selective optical filter configured to:
• receive an optical signal at an add wavelength from the add port and transmit said optical signal at the add wavelength towards the common port;
• and
• receive optical signals from the common port and reflect optical signals not at the add wavelength;
• a second wavelength selective optical filter configured to receive said optical signals from the common port reflected by the first wavelength selective optical filter and transmit an optical signal at a drop wavelength, different to the add wavelength, the optical signal being from among said optical signals received from the common port and reflected by the first wavelength selective optical filter;
• a drop port;
• an optical waveguide configured to receive said optical signal at the drop wavelength transmitted by the second wavelength selective optical filter and route said optical signal to the drop port;
• and
• an express port,
• wherein the second wavelength selective filter is additionally configured to:
• receive said optical signals from the common port reflected by the first wavelength selective optical filter and reflect optical signals not at the drop wavelength towards the express port;
• receive optical signals from the express port and reflect optical signals not at the drop wavelength;
• wherein the first wavelength selective filter is additionally configured to receive said optical signals from the express port reflected by the second wavelength selective filter and reflect said optical signals towards the common port.