Difference between CWDM and DWDM
This page describes on CWDM vs DWDM describes difference between CWDM and DWDM fiber optic technologies.
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The figure-1 depicts CWDM based fiber system. As shown it is used to transmit 4 different applications using single optical finer instead of pair of fiber cables. Different applications are using different light wavelengths which helps in multiplexing and de-multiplexing applications at transmit and receive end.
DWDM-Dense Wavelength Division Multiplexing
The figure-2 depicts DWDM system consisting of transmitter and receiver parts. Typically DWDM consists of MUX, DEMUX, isolators, circulators, EDFA (Erbium Doped Fiber Amplifier) etc.
DWDM system basics
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| Specifications/Features | CWDM | DWDM |
| Full form | Coarse Wavelength Division Multiplexing,WDM system having less than 8 active wavelengths per optical fiber | Dense Wavelength Division Multiplexing, WDM system having more than 8 active wavelengths per optical fiber |
| characteristic | Defined by wavelengths | Defined by frequencies |
| capacity | lower | higher |
| cost | low | high |
| Distance | short range communication | long range communication |
| Frequencies | uses wide range frequencies | uses narrow range frequencies |
| Wavelength spacing | more | less, hence can pack 40+ channels compare to CWDM in the same frequency range |
| Amplification | light signal is not amplified here | light signal amplification can be used here |
| Drift | Wavelength drift is possible | Precision lasers are needed to keep channels on the target |
| Spectrum utilization | Breaks the spectrum into big chunks | dices the spectrum into small pieces |
| No. of active wavelengths per fiber | Fewer than 8 | More than 8 |