An optical package includes a substrate made of a first material having an upper surface and a lower surface. The substrate further includes at least one cavity opening onto an upper surface of the substrate. Electrical connection vias extend through the substrate. An electronic integrated circuit chip is mounted on the upper surface of the substrate in a position so as to cover the at least one cavity. The electronic integrated circuit chip includes an integrated optical sensor. Each cavity is filled with a second material having a thermal conductivity greater than the thermal conductivity of the first material. The electrical connection vias are arranged on either side of each cavity and between two cavities.