2 Systems with Wavelength Division Multiplexing - CWDM and DWDM grid
2.2 CWDM and DsWDM grid

Grid spacing in CWDM and DWDM systems
Technology | CWDM | DWDM – regional networks | DWDM – long-distance networks
Number of channels (wavelengths) | 4-16 | 32-80 | 80-160
Bands | O, E, S, C, L | C, L | C, L, S
Channel spacing | 20 nm or more (2500 GHz or more) | 0.8 nm, 100 GHz | 0.4 nm or less – 0.2 nm or 0.1 nm, (50 GHz or less)
Transmission capacity per channel | 1.5 Gbps | 10 Gbps | 10-40 Gbps
Fibre capacity | 20-40 Gbps | 100-1000 Gbps | Tens of Tbps
Laser type | Non-cooled DFB or FP | Cooled DFB | Cooled DFB
Reach | 50-80 km | 100 km | 1000 km
Price | Low | High | Highest

CWDM and DWDM operating wavelengths (exemplary).