Minimising crosstalk in microchannel free-space optical interconnects with the presence of higher order modes

Abstract

We investigate the combined effect of the diffraction-caused crosstalk noise (DCCN) and the stray-light crosstalk noise (SLCN) on the performance of FSOI system. A numerical simulator was employed in this study to investigate OI channel design. We determine that there exists an optimal focal length, which maximises the signal-to-noise ratio (SNR) by minimising the combined effects of DCCN and SLCN. For the fundamental mode, the optimal focal length is approximately 750µm; for both LG 01 and LG 10 modes, the optimal focal length occurs between f = 650 µm and f = 700 µm, depending on the interconnection distance and array pitch.