An optoelectronic module assembly includes an optoelectronic module. The module includes: an active optoelectronic component in or on a mounting substrate, an optical sub-assembly, and a spacer disposed between the mounting substrate and the optical sub-assembly so as to establish a particular distance between the active optoelectronic component and the optical sub-assembly. The optoelectronic module assembly also includes a recessed substrate including first and second surfaces, wherein the second surface is in a plane closer to the optical sub-assembly than is the first surface. The optoelectronic module is mounted on the first surface. The second surface is for mounting other components.