Study On Coupling Technology Between Double-Cladding Fiber And Laser Diode Array

Benefit from the particular structure of the double-clad fibers(DCF),double-clad fiber lasers(DCF)are being developed rapidly these years and are attracting increasing attention. The double-clad high-power lasers and amplifiers in optical communications, the free space communications systems, fiber optic sensing, as well as fiber-based microwave signals in the transmission and processing have a wide range of needs and applications. The development of double-clad fiber laser brought a new laser-pumped technology, cladding - pumped technology, How to increase the coupling efficiency from the semiconductor laser to double-clad fiber cladding is the core problem. Such a double-clad high-power laser and amplifier's pump source is the laser diode array generally. Therefore, how to pump efficient coupling into the double-clad fiber (DCF), will become the decision performance of high-power lasers and amplifiers key technology. Double-clad fiber laser pump coupling technology generally can be divided into two types, end-coupling and side coupling technology..In my research, I first discusses double-clad fiber laser pump coupling and the development of this technology, Then analyze the double-clad fiber structural features, focus on analyzing the structure of the cladding circular and rectangular, double-clad fiber absorption characteristics, analyze the impact of fiber coupling which result from the machinery of laser and optical fiber alignment error, including axial error, error angle and vertical error and establish a theoretical model then simulat the outcome. Through a comparative analysis of various coupling structure, as insufficient of end coupling ,we discuss some kinds of side-pumped coupling and do some comparative analysis .Finally I present a new production of a V-groove method of side-pumped technology. Based on the assumption that both the fundamental mode field of the laser beam and the fiber was approximated by a Guassian beam, a maximum coupling efficiency of 82% was predicted by the theory when the distance between the laser and the fiber was 18um.For a fixed distance between the laser and the fiber, a maximum coupling efficiency was achieved when the angle of the v-groove was 4°-5°.And the coupling efficiency decreased rapidly when the angle was above 10°.