Disclosed is a CMOS image sensor, which can minimize a reflectance of light at an interface between a photodiode and an insulating film, thereby enhancing image sensitivity. The WDM transmission system includes an optical transmission line for transmitting WDM signals in four or more channels with a channel spacing therebetween of not more than 0. Present inventive algorithms operate in a variety of peer and server network configurations while providing significant improvement in convergence speed and accuracy.