brief introduction: Optical fiber transmission device refers to the optical fiber processing into a certain function of the optoelectronic devices, the single-mode fiber based optical fiber devices have been widely used. Fiber amplifier, fiber laser, fiber coupler, fiber polarizer and fiber filter are the main fiber devices used in fiber communication. Their main functions are to amplify light directly, generate laser, distribute or combine optical signal power between different optical fibers, change the input lig