An optical module and a method of manufacturing an optical module are provided. The optical module includes a carrier, an electronic component, a lid, a diffuser and a bonding layer. The electronic component is disposed on the carrier. The lid is disposed on the carrier. The lid has a first cavity to accommodate the electronic component. The lid defines a first aperture over the first cavity. The diffuser is disposed within the first aperture. The bonding layer is disposed between the diffuser and a sidewall of the first aperture.