In the construction of optical transmission networks, long-distance transmission needs to consume a lot of optical fiber resources. WDM passive components can multiplex multiple optical signals into one optical fiber, expand transmission capacity and save optical fiber resources. Among them, CWDM and DWDM devices are two of the more commonly used devices. Equipped with corresponding color light modules, different passive wavelength division optical transmission solutions can be realized.

Mux&&Demux multiplexer and demultiplexer
Mux demux is a wavelength division multiplexing product based on TFF (thin film filter). It multiplexes optical signals of different wavelengths into a single optical fiber for transmission, and uses demultiplexing at the receiving end to decompose the signal in the optical fiber into different Wavelength of the signal.

CWDM Coarse Wavelength Division Multiplexer and Demultiplexer
The CWDM MUX coarse wavelength division multiplexer has a wavelength of 1270-1610nm and a wide wavelength interval of 20nm. It has low requirements on lasers and effectively reduces network operating costs. There are two transmission schemes, single-fiber bidirectional and dual-fiber bidirectional.

Single-fiber two-way transmission system: Single-fiber two-way use wavelength division multiplexing (WDM) technology, which combines different wavelengths for sending and receiving into one optical fiber without mutual interference (if the same optical fiber transmits and receives wavelengths, it is indistinguishable) , So there is one more WDM device for single-fiber bidirectional, and the price is higher relative to dual-fiber.

The dual-fiber bidirectional and BIDI optical modules have the same practical effects. The only difference is that customers can choose single-fiber or dual-dual fiber according to their needs. Single-fiber bidirectional optical modules are more expensive, but can save one fiber resource, which is a better choice for users with insufficient fiber resources. The dual-fiber bidirectional optical module is relatively cheap, but one more fiber is needed. If the fiber resources are sufficient, you can choose a dual-fiber optical module.