|
At present, there are some problems in the digital scanning imaging methods of multimode optical fiber, such as poor quality of focused spot, large amount of calculation and long time in the forming process of focused spot. In order to solve the above problems, a parallel phase compensation method based on liquid crystal spatial light modulator (LCSLM) is proposed to achieve fast point-focused scanning of multimode fiber (MMF). The parallel algorithm, which includes the two processes of collecting online specklegrams and calculating offline phase masks, calculates the compensation phase masks so that the phase masks can be loaded on SLM in turn to generate a series of focused spots at different predefined positions, which greatly saves time. Experiments demonstrate that this method doesn’t need many iterations, and the phase compensation mask used for focusing spot at a predefined position on the MMF output facet can be obtained by using a two-step phase-shifting technique, and a series of phase compensation masks can be quickly obtained by using the parallel method, so as to form focused spots at different predefined positions. Experimentally, we obtained 100 focused spots, the average focused efficiency was 30.12%, the average focused diameter was 2.3382μμm, and the quality of the focused spot was improved compared with previous reports.
|
