Theoretical And Experimental Study Of Fiber Coupled Acousto Optic Modulator

Different from the free-space modulators, optical fiber coupled acousto-optic modulator(FCAOM) has many advantages, such as low insertion loss, compact structure, small size, seal design, no moving parts and high reliability. With the development of laser technology and fiber optic technology, fiber-coupled acousto-optic modulator by virtue of its excellent properties, is widely used in pulsed fiber lasers, fiber amplifiers, pulse acquisition and other areas. Compared with conventional semiconductor lasers, fiber lasers have excellent properties such as simple structure, good slope efficiency, excellent thermal performance, good output beam and so on. The fiber-coupled acousto-optic modulator applied to the 1064 nm 10W / 20 W pulsed fiber laser marking was studied in this paper. As one of the key components of Q, its performance affects the performance of the entire pulse fiber laser. Therefore, the fiber-coupled acousto-optic modulator has a certain practical significance for theoretical and experimental research.Firstly, the structure of the common fiber lasers was introduced and the effect of fiber-coupled acousto-optic modulator fiber lasers on fiber lasers was introduced too. The current domestic and international research status acousto-optic devices and fiber-coupled acousto-optic modulator was briefly discussed. Via analyzing the gap, the fiber coupler modulator performance characters were developed at the same time.Then, the study was investigated from the theoretical and experimental aspects, respectively. Theory: By analyzing fiber-coupled acousto-optic modulator structure and composition, as well as sound and light interaction theory qualitatively, the three main factors affecting the performance were analyzed. Because of its unique structure, two fiber collimator coupling efficiency theory study need to be analyzed and simulated. According to performance requirements, drive requirements, design, design of each module, made circuit boards for testing was proposed. Experiments: According to the analysis of sound and light in front of interaction theory, load the driver acousto-optic crystal signal was given. The influence of fiber collimator beam diameter and divergence angle of insertion loss and switching time was investigated in the experiment. The suitable one was selected for coupling the fiber collimator.Finally, for a given acousto-optic crystal, load drive signal, selecting the beam diameter 375 um, the beam divergence angle is 2.3mrad light collimator, fiber acousto-optic modulator coupled to test, to give an insertion loss of 2.3dB, light pulse rise time of 60 ns, extinction ratio of 49 dB, reached the design specifications, applied to pulsed fiber laser, good performance.