We propose and demonstrate an integrated reconfigurable fiber-chip mode converter with multi-mode coupling functionality. The converter is composed of an inverse taper array, a cascaded Y-junction and a waveguide crossing, as well as a heater to control the mode conversion states. The fundamental and first-order modes can be coupled and converted simultaneously between fiber and chip without additional mode multiplexer/demultiplexer. Higher than −7 dB coupling efficiencies with 1-dB bandwidth larger than 100 nm can be experimentally observed for all the coupling cases. The measured modal crosstalk are −10 and −15 dB in the cases of fundamental and first-order modes inputting, respectively.

中文翻译：

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具有高效多模耦合功能的可重构光纤芯片模式转换器

我们提出并演示了具有多模耦合功能的集成可重构光纤芯片模式转换器。转换器由倒锥形阵列、级联 Y 结和波导交叉以及控制模式转换状态的加热器组成。基模和一阶模式可以在光纤和芯片之间同时耦合和转换，无需额外的模式复用器/解复用器。对于所有耦合情况，都可以通过实验观察到高于 -7 dB 的耦合效率和大于 100 nm 的 1-dB 带宽。在基模和一阶模输入的情况下，测得的模态串扰分别为 -10 和 -15 dB。