· Incompatibility with Single-mode Fiber: Multi-mode optical modules cannot work with single-mode fiber due to differences in core diameter and transmission characteristics. A small portion of the transmitted light gets captured. This leads to high attenuation and frequent link drops. I suggest you avoid such setups. These components offer distinct characteristics and compatibilities that cater to different network requirements. Each module type uses LC interfaces, and professionals commonly group them together under the name LC SFP modules. They mainly differ in the type of optical fiber they operate. I have SFP-10G-SR Multimode module connected to two switch. Any reasons why it is happening. Differences Between Single-Mode and Multi-Mode.