A pump-LD (Laser Diode) is a light source for a fiber amplifier used in optical communication networks. Types of pump-LDs include a simple structure FP-LD (Fabry-Perot Laser Diode) and an FBG-LD. The major comp nent of optical transmitters is an optical source. Fiber-optic communication systems often use semiconductor optical sources such as light-emitting diodes (LEDs) and semiconductor lasers beca se of several inherent advantages offered. ITU-T is promoting the commercialization of coherent transceivers that use phase modulation, such as DP-QPSK, for long-distance transmission, as well as research into methods for modulating a greater number of values (16 QAM and 32 QAM) in order to increase the transmission capacity without. Semiconductor optoelectronic devices are various functional devices made by utilizing the light-to-electricity conversion effect. That is to say, through the conversion and control of light and electricity, these devices can achieve a variety of functions. It answers the big-picture questions: * What will the network look like? * Where will it cover? * How much capacity will it carry? HLD is established in the initial. Optical Fiber (OFC): Thin strands of glass/plastic that guide light. Singlemode Fiber (SM / SMF): Fiber with a small core (~9µm) that allows only one mode of light. Used for long-distance, high-speed.
