Tunable optical add/drop multiplexer

A tunable optical add/drop multiplexer (T-OADM), comprising:

• a first port configured to input an input beam comprising at least two wavelengths,
• a first beam adjustment apparatus configured to adjust a transmission direction of the input beam based on a first signal dropped by the T-OADM, so that the input beam is incident onto a first optical filter at a first incident angle corresponding to a wavelength of the first signal,
• the first optical filter configured to:
• receive a beam that is incident at the first incident angle, and
• split an incident beam into a first transmitted beam and a first reflected beam, wherein a wavelength of a beam comprised in the first transmitted beam is different from a wavelength of a beam comprised in the first reflected beam,
• a second beam adjustment apparatus configured to adjust a transmission direction of the first transmitted beam based on the first incident angle,
• a second port configured to output the first transmitted beam, and
• a third port configured to output the first reflected beam, wherein;
• the first beam adjustment apparatus is further configured to adjust a transmission direction of the first reflected beam based on the first incident angle.