Monte-Carlo simulations of multimode speckle noise in photonic summation devices

Abstract

Monte-Carlo simulations of optical speckle noise are performed to predict the range of gain fluctuations for photonic devices which multiplex many single-moded inputs into single multimode waveguides. Here, two waveguides are simulated which bound the cases of interest: a few mode fiber and a standard multimode fiber. When fully-excited and after spatial-filtering by a 10µm photodiode, the former’s gain variations can range up to the mean value of the gain itself, ΔG ≈ 〈G〉, whereas for the latter, ΔG ≈ 3.4〈G〉. In certain cases, ΔG can be reduced by offsetting the photodiode relative to the waveguide, results which cannot be predicted using standard analytical speckle noise theories.