In one example embodiment, an optoelectronic module comprises a body, a signal ground, and an OSA. The body is connected to chassis ground and defines a cavity within which one or more components are disposed. The optical subassembly is disposed in the body cavity, has one or more components connected to signal ground, and comprises a header assembly, a housing, and one or more containment structures. The header assembly houses one or more components that generate EMI emissions and includes an optical aperture. The housing includes a port and a barrel. The port defines a fiber receptacle and the barrel defines a cavity that at least partially receives the header assembly. The containment structure(s) at least partially contain the EMI emissions within the OSA.