  We investigate high-fidelity multiple beam splitting in Hermitian and
non-Hermitian symmetric coupled waveguides with one input and 2N output
waveguide channels. In Hermitian systems, we realize adiabatically light
splitting in resonant case based on the stimulated Raman adiabatic passage
(STIRAP) and arbitrary proportion from the middle waveguide to outer waveguides
in propagation coefficients mismatch case using shortcuts to adiabaticity (STA)
technique. In non-Hermitian systems with even waveguides being dissipative, the
compact and robust beam splitting can be achieved by eliminating the
non-adiabatic coupling via the non-Hermitian STA method. We further verify the
feasibility of our theoretical predictions by means of the beam propagation
method (BPM). The suggested multiple beam splitters open new opportunities for
the realization of on-chip high-bandwidth photonics with high fidelity in short
distances.
