What? And dispersion?
Dispersion is also an important factor affecting the transmission of optical signals.
Dispersion: The widening of the bandwidth caused by a light pulse traveling a distance along a fiber. It is the main factor limiting the transfer rate.
cause of dispersion
• Intermodal dispersion: Occurs only in multimode fibers because light in different modes travels along different paths.
• Material dispersion: Different wavelengths of light travel at different speeds.
• Waveguide Dispersion: Occurs because light energy travels at slightly different speeds as it travels through the core and cladding. In single-mode fiber, it is very important to change the dispersion of the fiber by changing the internal structure of the fiber.
Effect of Fiber Material on Propagation
• Glass fiber: both the core and the cladding are glass, with low loss, long transmission distance and high cost;
• Silicone optical fiber: the core is glass, the cladding is plastic, the characteristics are similar to those of glass fiber, and the cost is lower;
• Plastic optical fiber: Both the core and the cladding are plastic, with high loss, short transmission distance and low price. It is mostly used for home appliances, audio, and short-distance image transmission.
Optical module
Optical modules are components that realize the conversion of optical signals and electrical signals. Common ones include GBIC, SFP, SFP+, XFP, SFF, CFP, etc.
GBIC vs SFP
The size of the GBIC optical module is too large, occupying too much space in the switch, so that more interfaces cannot be provided on the panel of the switch. Therefore, in recent years, GBIC optical modules have been gradually replaced by SFP optical modules.
