What is the optical channel spacing of coarse wavelength division multiplexing (CWDM) systems?

Coarse Wavelength Division Multiplexing (CWDM) systems utilize an optical channel spacing of 20 nanometers. This standard channel spacing allows for the efficient multiplexing of multiple wavelengths over a single optical fiber, making CWDM systems an effective solution for increasing bandwidth without needing more fiber. The 20 nm spacing enables a wide range of wavelengths to be used, specifically from 1270 nm to 1330 nm, which can accommodate several channels for data transmission while also ensuring that the interference between adjacent channels is minimized.

When considering other typical optical channel spacings, options like 10 nm or 15 nm are indicators of Dense Wavelength Division Multiplexing (DWDM) systems, which aim for finer spacing to accommodate a larger number of channels. However, the design of CWDM prioritizes a broader spacing to facilitate simpler, less costly deployment over shorter distances compared to DWDM. Hence, the choice of 20 nm effectively characterizes the CWDM system's operational parameters.