CWDM MUX DEMUX SYSTEMS

18 different frequencies used in CWDM

This is MetroSAE chassis  This chassis supports two multiplexers and 12 optical adapters. 

• CWDM stands for Coarse Wavelength Division Multiplexing.
• ITU-T ha defined  18 wavelengths separated by 20nm in the O, E, S, C, and L optical bands for this purpose.
•  But, the most popular single mode fiber is of type G652.
• This fiber can accommodate the following 8 wavelengths efficiently:
• 1470nm, 1490nm, 1510nm, 1530nm, 1550nm, 1570nm, 1590, and 1610nm

CWDM   16 channel cwdm demux

What is G.652 optic fiber?

The ITU has classified the optic fibers based on its properties as under:

ITU G.65= multimode 50/125 micron graded-index fiber. 
ITU G.652=Single-mode NDSF (non-dispersion-shifted fiber). This fiber is in most of the cable that was installed in the 1980s. Optimized in the 1,310-nm range. Low water peak fiber has been specifically processed to reduce the water peak at 1400 nm to allow use in that range. There are 4 subcategories: G.652A,G.652B.G.652C,G.652D


ITU G.653    Covers single-mode dispersion-shifted optical fiber. Dispersion is minimized in the 1,550-nm wavelength range. At this range attenuation is also minimized, so longer distance cables are possible.

ITU G.654: Covers single-mode fibre which has the zero-dispersion wavelength around 1300 m wavelength which is cut-off shifted and loss minimized at a wavelength around 1550 nm and which is optimized for use in the 1500-1600 nm region. 

ITU G.655    Covers single-mode NZ-DSF (nonzero dispersion-shifted) fiber) , which takes advantage of dispersion characteristics that suppress the growth of four-wave mixing, a problem with WDM (wavelength division multiplexing) systems. NZ-DSF supports high-power signals and longer distances, as well as closely spaced DWDMchannels at rates of 10 Gbits/sec or higher. G.655 is optimized for WDM and long-distance cable runs such as transoceanic cables. It uses dispersion to reduce the effect of four-wave mixing (FWM), which occurs in DWDM systems when three wavelengths mix in such a way to produce a fourth wavelength that overlays and interferes with the original signals.

ITU G.657   Covers bend-insensitive single- mode fiber.