Optical beam director

A chip-based optical beam director, the beam director including:

• an input to receive light of a range of different wavelengths, including a light of a first wavelength channel and a light of a second wavelength channel, different to the first wavelength channel;
• an output to emit directed light from the optical beam director;
• a dielectric layer on an insulator;
• and
• one or more sets of multiple subwavelength structures formed on or in the dielectric layer in a light path from the input to the output, each set of the multiple subwavelength structures having a periodic arrangement, the periodic arrangement causing the first wavelength channel to be dispersed in a first direction within the light path and the second wavelength channel to be dispersed in a second direction within the light path, different to the first direction;
• and
• wherein at least one set of the one or more sets of multiple subwavelength structures is formed as a subwavelength structured blazed diffraction grating configured to direct the light on a plane defined by the dielectric layer, the subwavelength structured blazed diffraction grating having a periodic arrangement associated with a grating period, and a blazed period that is larger than the grating period.