An electronic package includes a substrate wafer having front and rear faces and a through passage having a front window and a blind cavity communicating laterally with the front window. A receiving integrated circuit chip is mounted on the rear face and includes an optical sensor situated opposite the blind cavity. A transparent encapsulant extends above the optical sensor and at least partially fills the through passage. An emitting integrated circuit chip, embedded in the transparent encapsulant, includes an optical emitter of luminous radiation. The emitting integrated circuit chip may be mounted to the front face or within the through passage to the receiving integrated circuit chip. The substrate wafer may further include a second through passage. The receiving integrated circuit chip further includes a second optical sensor situated opposite the second through passage. A cover plate is mounted to the front face at the second through passage.