Recently, Wavelength Division Multiplexing (WDM) technology is warmly welcomed by internet users all around the world. It is a technology that combines two or more kinds of optical signals at different wavelengths and transmits them on a single optical fiber. By using WDM technology, fiber optic transceivers can transmit signals at different wavelengths, which is a cost-effective solution for high capacity in network applications. WDM transceivers can be divided into two basic types. One is...