Photonic integrated circuit and opto-electronic system comprising the same

A photonic integrated circuit comprising:

• an indium phosphide, InP,-based substrate that is provided with a first InP-based optical waveguide and a neighboring second InP-based optical waveguide;
• a dielectric planarization layer that is arranged at least between the first optical waveguide and the second optical waveguide, wherein at least between the first optical waveguide and the second optical waveguide, the dielectric planarization layer is provided with:
• a recess that is arranged to reduce or prevent optical interaction between the first optical waveguide and the second optical waveguide via the dielectric planarization layer;
• wherein at the location of the recess, the dielectric planarization layer has:
• a first sidewall that is arranged sloped towards the first optical waveguide;
• and
• a second sidewall that is arranged sloped towards the second optical waveguide;
• and
• a first dielectric protective layer that is arranged to cover at least the first sidewall and the second sidewall of the dielectric planarization layer.