With the Internet, high-speed IP data traffic growth, resulting in demand for transmission bandwidth is increasing. Though DWDM (Dense Wavelength Division Multiplexing) technology as the most effective way to solve the line bandwidth expansion, but CWDM (coarse wavelength division multiplexing) technology over DWDM system has advantages in cost and maintainability.

WDM (Wavelength Division Multiplexing), Lightwave share with technology, is transmitted simultaneously in a single optical fiber technology multi-wavelength optical signal.