Yes, it is possible to splice single mode fiber to multimode fiber using a mode conditioning patch cord. Fiber media converters quietly solve a big, practical problem: they bridge copper Ethernet to fiber and extend links far beyond copper's reach. In real networks such as campuses, factories, metro POPs converters let you reuse existing switches and still run fiber for long distance, EMI immunity. In different cabling environments, optical fiber communication may require multimode to single-mode conversion or single-mode to multimode conversion. 📝 Why Can't You Directly Connect SMF and MMF? At its heart, the incompatibility is physical. Single-mode fibers have a smaller core diameter, typically 8 to 10 microns.