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5G front haul CWDM

Time:2019-11-01 Views:856
Why 5G front-haul CWDM module use the 6 channels CWDM wavelengths, 1271nm 1291nm 1311nm 1331nm 1351nm 1371nm?
Because one base station has 3 sector, each sector needs 2 channels as transmission and receiver wavelength, so total 6 channels.

Why choose CWDM not DWDM?
The WDM module working temperature is -40 to 85°C, the range is 125, DFB laser wavelength drift 0.08-0.1nm for each 1°C, for the 125 range, the drift is 13nm max. CWDM has 20nm channel spacing. That is why use CWDM filter. In addition, not need TEC to save cost.

Why use 1271nm 1291nm 1311nm 1331nm 1351nm 1371nm, not use 1471nm-1610nm?
Because 1310 window is low optical dispersion, and support DFB laser, not need EMI laser, which can save cost. That is why using these channels. 
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