提出了一种新型全光纤LP02模宽带模式转换器.基于模式匹配原理采用双芯光纤设计, 利用LP11模作为中间过渡模式, 实现了宽带模式转换.运用光束传播法和模式耦合理论分析了光纤参量对有效折射率的影响, 选择合适的光纤参量实现了模式匹配, 分析了纤芯距离等参量对模式转换效率和带宽的影响, 对比相同光纤参量下, 直接和间接模式转换方法, 数值模拟表明, 采用间接法能够有效提高模式转换带宽, 当要求转换效率大于80%时, 这种模式转换器带宽能够达到121 nm.

An all-fiber LP02 broadband mode converter is proposed in this paper. Boardband is achieved when LP01 mode is converted to LP02 mode by using LP11 mode as an intermediate mode based on the mode matching principle and the designed dual-core fiber. The relationship between fiber parameters and the effective index was investigated as well as structure parameters and conversion bandwidth, and the structure is optimized by using the beam propagation method and the mode coupling theory. The bandwidth is compared of the method convert LP01 mode to LP02 mode directly with the method using LP11 mode as an intermediate mode. Simulation results show that the intermediate method can improve the bandwidth and conversion bandwidth can reach 121nm with a conversion efficiency over 80%.