MUX/DEMUX in WDM Systems

Wavelength division multiplexing (WDM) is a technology in which two or more optical carrier signals of different wavelengths (carrying various information) are converged together at the transmitting end by a multiplexer and coupled into the same optical fiber of an optical line for transmission.

CWDM: wavelength spacing of 20 nm, with relatively wide wavelength spacing.

DWDM: wavelength interval is between 0.2 and 1.2nm.

 

Wavelength division multiplexer commonly used in two kinds: filter-type mux demux, chip-type AAWG (flat top, Gaussian)

Do you know the principle of filtered mux demux? Please see the following diagram


At the Mux end, the light of various wavelengths is passed through the filter individually, then reflected and coupled into a single fiber for transmission. At the demux end, all wavelengths of light pass through the filter together, filtering out one wavelength of light, reflecting all other wavelengths to the next filter, then filtering out the next wavelength of light, and repeating this process, we can demux all wavelengths of light.

Insert loss at the Mux side: 1470nm<1490nm<1510nm<1530nm<1550nm<1570nm

Insertloss at the Demux side:

1470nm>1490nm>1510nm>1530nm>1550nm>1570nm

 

AWG is a planar waveguide device, which is an array of waveguide gratings fabricated on a chip substrate using PLC technology.AWG has both focusing and dispersion functions, that is, allowing the same wavelength of light to focus on a point, while for different wavelengths of light, allowing the focus to undergo dispersion shifts. Compared with FBG and TTF, AWG has the advantages of high integration, large number of channels, low insertion loss, and easy to produce in batch automation.

 

HTF's mux demux can be made in different types, please see the figure below. If you require, we can customize it for you.


 

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