“…The interval between two waveguides is 12 μm and the total length of the incoupler area is about 1.5 cm. Though for a MMI, the correlation between wavelength and the MMI dimension cannot be neglected [4], other light separating structures such as waveguide splitters [5,10,16] will be suitable for a light source with a wide spectral range as well. In this simulation, LEDs with narrow spectral range are in use [6].…”