An All-Fiber Multimode Interference Device for Power Splitting in Few Mode Fiber Networks

We show an all-fiber multimode interference device for splitting the power propagating in a few mode fiber (FMF) into four (4) identical FMF ports. The splitting operation is achieved efficiently for individual modes, as well as a complex field comprising multiple propagating modes, ensuring mode transparent operation. The fabricated device, with length <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\leq 1$</tex-math></inline-formula> cm, shows uniform power splitting in the C-band with less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.8$</tex-math></inline-formula> dB power variation among the output ports. The device could provide a possible solution for power splitting in future FMF networks employing the mode division multiplexing technique.