Mode conversion based on dual-phase modulation utilizing interference of two-phase-modulated beams

摘要

To realize mode conversion with high accuracy and efficiency, we propose a new method based on dual-phase modulation (DPM) that utilizes the interference of two-phase-modulated beams. DPM realizes complex amplitude modulation with the interference of two-phase-modulated beams generated by phase-type spatial light modulators (PSLMs). DPM realizes highly efficient conversion using the interference of light rather than the diffraction that is conventionally used for complex amplitude modulation. Moreover, DPM enables the suppression of modal crosstalk (MXT) utilizing the destructive interference between two unwanted 0th beams that occur from PSLMs. In this paper, we experimentally confirmed that DPM can reduce the amount of the unwanted 0th beam. Then, we performed an experiment on mode conversion based on DPM and achieved a modal crosstalk of less than -20 dB and an optical loss of less than 10 dB.