Mode　exchangers　serve　as　critical　functional　units　in　on-chip　mode-division　multiplexing　systems,　where　their　compactness　and　performance　metrics　directly　influence　the　integration　density　and　transmission　capacity　of　communication　systems.　To　address　the　technical　bottlenecks　of　existing　devices　in　mode　scalability　and　conversion　efficiency,　this　study　proposes　a　novel　design　of　ultra-compact　multi-mode　exchangers　based　on　Bezier　curve　waveguides.　Through　parametric　optimization　of　the　functional　region　using　a　direct　binary　search　algorithm,　three　novel　mode　exchangers　(ME00/12,　ME01/22,　and　ME02/11)　are　successfully　designed,　with　all　physical　dimensions　confined　within　4.8　×　1.8　μm2.　Theoretical　simulations　reveal　that　these　devices　achieve　insertion　losses　＜　1.0　dB　and　crosstalk　＜　−　10.0　dB　across　wavelength　ranges　of　196　nm　(1400–1596　nm),　187　nm　(1513–1700　nm),　and　155　nm　(1515–1670　nm),　respectively.　These　operational　bandwidths　cover　the　C　+　L　primary　communication　bands　and　parts　of　the　S/U　extended　bands.　Experimental　validation　within　the　1500–1580　nm　range　confirms　the　theoretical　predictions.　Compared　to　previously　reported　designs,　the　proposed　devices　exhibit　improved　mode　conversion　performance.　Furthermore,　a　mode　add-drop　multiplexing　system　incorporating　ME00/12　and　ME02/11　was　constructed.　Experimental　results　demonstrate　insertion　losses　＜　2.4　dB　and　crosstalk　＜　−　10.8　dB　across　all　mode　channels　within　the　1530–1570　nm　operational　window.　The　presented　mode　exchangers　and　mode　add-drop　multiplexing　systems　provide　engineering-viable　solutions　for　constructing　high-performance　mode-division　multiplexing　systems.　©　2025　Elsevier　Ltd