Mode division multiplexing is a promising technique that enables highly parallel and compact on-chip optical communications, but its scalability has been hampered by the crosstalk so far. By exploiting supermodes in closely packed waveguide arrays, low crosstalk between waveguides can be achieved when phase mismatch condition is met. This paper considers two techniques to achieve phase mismatch: waveguide non-uniformity and waveguide bending. The aim is to experimentally assess the BER performance on both straight and curved arrays of closely packed waveguides. Experimental results at 10 Gb/s demonstrate the simultaneous data transmission over different waveguides with a power penalty <0.5 dB at BER = 10−9 in straight non-uniform arrays and sharp bends.