• Less scalable - 8 lambdas • Lower complexity and cost
1510nm
EDFA Bandwidth
1550nm
1610nm
Coarse Wavelength Division Multiplexing (CWDM) employs multiple light wavelengths to transmit signals over a single optical fiber, just like DWDM. CWDM is a less robust WDM technology:
CWDM uses significantly wider wavelength spacing—20nm as opposed to 0.8nm for DWDM.
CWDM therefore supports fewer wavelengths, and therefore less bandwidth, than DWDM. Number of channels varies per vendor, but in general DWDM can support about 20 times the bandwidth of CWDM.
No amplification is possible with CWDM because CWDM uses wavelengths that cannot be amplified with EDFA amplifiers. This limits the effective distance of CWDM.