So, to cut right to the chase, you can generally tell if fiber is multimode or singlemode by examining the cable's jacket color, looking for printed markings on the jacket, checking the connector type, and if all else fails, by measuring the core diameter or using an optical. So, to cut right to the chase, you can generally tell if fiber is multimode or singlemode by examining the cable's jacket color, looking for printed markings on the jacket, checking the connector type, and if all else fails, by measuring the core diameter or using an optical. The two main types — Single Mode (SM) and Multimode (MM) — differ in construction, performance, and application. This guide explains how to identify them by appearance, labeling, and technical specifications, helping you make the right choice for your installation. Fiber optic cables transmit data as pulses of light through. To recap Optical Fiber can be divided into Multimode Fiber (MMF) and Single-Mode optical fiber (SMF). Multimode Fiber (MMF) has a core diameter, typically 50–100 micrometers, has ability to transfer multiple modes of light through the fiber core, uses lower-cost electronics (LED, VCSEL) operates at. Multi-mode optical fiber is a type of optical fiber mostly used for communication over short distances, such as within a building or on a campus. Multi-mode links can be used for data rates up to 800 Gbit/s. Correctly distinguishing single-mode and multi-mode.