CWDM optical transceiver using CWDM technology, which is used to realize the connection between existing network devices and CWDM multiplexers or demultiplexers. When used with a CWDM multiplexer or demultiplexer, a CWDM optical transceiver can increase network capacity by transmitting multiple data channels with individual optical wavelengths (1270nm to 1610nm) on the same single fiber.