Laser source and method for forming the same

A method for forming a laser source comprising:

• forming an active medium over a substrate, the active medium comprising:
• a first metallic conductive layer arranged proximate to the substrate;
• a second metallic conductive layer over the first metallic conductive layer;
• and
• an active region sandwiched between the first metallic conductive layer and the second metallic conductive layer;
• and
• forming a photonic crystal structure in the active region and the second metallic conductive layer, the photonic crystal structure comprising:
• a first domain comprising a plurality of first holes defined therein, the first domain being associated with a first set of Chern numbers;
• and
• a second domain comprising a plurality of second holes defined therein, the second domain being associated with a second set of Chern numbers,
• wherein the plurality of first holes and the plurality of second holes are arranged to define an interface region between the first domain and the second domain, the interface region defining an optical cavity for lasing,
• wherein the plurality of first holes and the plurality of second holes are defined through an entire depth of the active region, and
• wherein the active region is arranged directly on the first metallic conductive layer.