Integrated optical structure for multiplexing and/or demultiplexing

An integrated optical structure for multiplexing and/or demultiplexing an optical signal, wherein the optical signal comprises optical channels of different frequencies or is formed by combining the optical channels, and wherein the integrated optical structure comprises:

• a main waveguide having two parallel side surfaces that delimit the main waveguide along its longitudinal sides and run parallel to its extension direction;
• a first waveguide which meets the main waveguide at a first region on one of the two parallel side surfaces;
• a plurality of second waveguides which meet the main waveguide at a second region on one of the two parallel side surfaces, wherein:
• the second region is spaced at a determined distance from the first region,
• the two parallel side surfaces of the main waveguide are arranged at a first angle relative to an extension direction of the first waveguide and a second angle relative to extension directions of the plurality of second waveguides, and and
• one or more waveguide extension structures configured to control a channel spacing of the optical channels of different frequencies that can be multiplexed via the second waveguides used as input waveguides and the first waveguide used as an output waveguide and/or demultiplexed via the first waveguide used as an input waveguide and the second waveguides used as output waveguides, wherein each waveguide extension structure is arranged adjacent to one of the two parallel side surfaces of the main waveguide at a region that is different to the first and the second region.