The present disclosure provides an optical module and a manufacturing process thereof. The optical module includes a carrier, a light source, a light detector, a molding compound and a lid. The light source is disposed adjacent to a surface of the carrier. The light detector is disposed adjacent to the surface of the carrier. The molding compound encapsulates the light source and the light detector, and includes at least one guiding structure. The lid is disposed between the light source and the light detector, and surrounds the light source and the light detector.