Hello, everyone. Today, I'd like to share my knowledge about SM fiber & MM fiber
Mode indicates the transmission path of optical signals that enter a fiber at a certain angular velocity. A fiber supports as many transmission modes as its diameter allows.
Fibers are classified into single-mode (SM) and multi-mode (MM) fibers based on the number of supported transmission modes.
MM Fiber:
A fiber that has a core diameter greatly exceeding optical wavelengths and permits tens and even hundreds of transmission modes is called MM fiber.
Because optical signals transmitted in different modes have different rates and phases, after long-distance transmission, issues such as time delays, broadened spectrums,and enlarged dispersion may happen. Therefore, MM fibers suit only low-rate and short-distance transmission.
SM Fiber:
A fiber that has a core diameter in the same order of magnitude as optical wavelengths and permits only one transmission mode (basic mode) is called SM fiber.
SM fibers suit large-capacity and long-distance transmission, and constitute the majority of fibers in the WDM system.
How are SM and MM fibers distinguished?
MM fibers are orange and marked as MM.
SM fibers are yellow and marked as SM.
SM and MM Optical Modules:
SM and MM optical modules must be used together with SM and MM fibers respectively.
The working bands are 850 nm for MM optical modules and 1310 nm and 1550 nm for SM optical modules.
Do not connect SM and MM optical modules.
How are SM and MM optical modules distinguished?
MM optical modules are marked as MLM.
SM optical modules are marked as SLM.
