WDM is a communication technology that combines a series of optical signals with different wavelengths and transmits them along a single optical fiber. At the receiving end, the optical signals of different wavelengths are separated by some method. WDM device uses this technology.
It distributes the optical power transmitted in one fiber to two or more fibers, or combines the optical power transmitted in multiple fibers into one fiber. Widely applied in FTTx, CATV, PON, OFLAN, etc.
Passive optical devices, only one-way optical light allowed to pass through, to prevent the bad influence of backward-transmitting light in the optical path on the light source and the optical path system caused by various reasons. Widely used in optical information processing system, optical fiber sensing and precision optical measurement system.