WDM: Multiplex optical signals of different wavelengths into the same optical fiber for transmission. We call this method Wavelength Division Multiplexing.
At the receiving end, the optical carriers of various wavelengths are separated by the demultiplexer, and then further processed by the optical receiver to restore the original signal.
DWDM: The wavelength interval is between 0.2 and 1.6nm, and the wavelength interval is relatively dense. Compared with CWDM, it has a larger capacity, more channels, supports EDFA optical amplification, and has a longhaul transmission distance.
Characteristics of traditional optical transmission
It takes up a lot of optical fiber resources; capacity expansion requires re-laying of optical cables, which is a huge amount of work, a long construction period, and consumes a lot of manpower and material resources;
It requires a large number of relay equipment, which is costly, occupies a large space in the computer room, and consumes a lot of power resources.
Characteristics of DWDM Technology
Save fiber resources: 40 cores of fiber were needed to transmit 40 services, but only 1 core of fiber is needed with DWDM technology;
Ultra-large capacity: single-core fiber can multiplex 120 waves, single wave can reach 400G, and total capacity can reach 48T;
Quick service opening: modular design of equipment, plug-and-play, quick service opening, only one week from solution design to service opening;
Greatly reduce energy consumption: 40 sets of amplifier equipment were needed for each amplifier station to transmit 40 services, but with DWDM system, only 1 set of amplifier is needed for each amplifier station, and energy consumption is reduced by 40 times;
Small space occupied in the computer room: with the old transmission solution, 40U of space was needed for each amplifier station to transmit 40 services, but with DWDM system, only 1U of space is needed for each amplifier station;
Low cost:
Equipment cost: 40 sets of amplifier equipment were needed for each amplifier station to transmit 40 services, but only 1 set of amplifier equipment is needed for each amplifier station with DWDM technology, and equipment cost is reduced by 40 times;
Fiber cost: 1000km For example, for a 40-channel service, you only need to rent 1 pair of fiber, instead of 40 pairs of fiber. Ginormous reduce the rental cost.
