Unitary transformation of general nonoverlapping-image multimode interference couplers with any input and output ports<xref rid="cpb_29_1_014206fn1" ref-type="fn">*</xref> <fn id="cpb_29_1_014206fn1"> <label>*</label> <p>Project supported by the National Key Research and Development Program of China (Grant No. 2018YFB2200202) and the National Natural Science Foundation of China (Grant No. 61804148).</p> </fn>

Unitary transformation of general nonoverlapping-image multimode interference couplers with any input and output ports* *

Project supported by the National Key Research and Development Program of China (Grant No. 2018YFB2200202) and the National Natural Science Foundation of China (Grant No. 61804148).

Li Ze-Zheng^{1, 2}, Han Wei-Hua², Li Zhi-Yong^{2, †}

(a) Diagram of 1 × 4 splitter based on cascaded MMI coupler, and (b) simulated light profile for 4-port output state with equal phase difference.