Electro-optical device with III-V gain materials and integrated heat sink

A method of fabricating an electro-optical device, the method comprising:

• providing two components of the electro-optical device, wherein:
• a first one of the components comprises a silicon substrate and a cladding layer on top of the silicon substrate, said providing the first one of the components comprises:
• providing a silicon on insulator wafer that comprises:
• the silicon substrate;
• a first oxide layer on top of the silicon substrate;
• and a top silicon layer on top of the first oxide layer;
• structuring the top silicon layer of the silicon on insulator wafer to obtain a silicon component;
• and
• depositing a second oxide layer on top of the first oxide layer of the wafer provided, so as to form said cladding layer, the latter comprising the first oxide layer and the second oxide layer, with the silicon component embedded therein;
• and
• a second one of the components comprises a stack of III-V semiconductor gain materials, designed for optical amplification of a given radiation,
• creating two cavities in said cladding layer, said creating comprising:
• etching two cavities separated by a residual portion of said cladding layer in between, the silicon component embedded in said residual portion;
• and
• filling the two etched cavities with an electrically insulating material to form respective thermal spreaders, wherein each thermal spreader has:
• a thermal conductivity larger than that of the cladding layer;
• and
• a refractive index that is lower than each of:
• the refractive index of the silicon substrate;
• and
• an average refractive index of the stack of III-V semiconductor gain materials for said given radiation, and
• wafer bonding the two components and structuring the stack of III-V semiconductor gain materials so as to obtain a structured stack that faces and at least partially overlaps the formed thermal spreaders and is in thermal communication with each thermal spreader.