  Secure communication in layered networks having differently preferred
participants has attracted a lot of research attention. Protocols for key
distribution in a layered network have been recently proposed in [M. Pivoluska
et al., Phys. Rev. A 97, 032312] by employing asymmetrically entangled
multiqudit states. Due to the employment of asymmetrically entangled multiqudit
states, the yield of these protocols is very low. To address this issue, in
this work, we have proposed semi-quantum secure communication protocols by
employing separable states only which give a better yield and a higher key
generation rate. As illustrations, we present two representative protocols. The
first protocol allows sharing of two keys simultaneously in a network of two
layers. The second protocol facilitates direct communication in one layer and
key distribution in the other. The separable states, i.e., coherent pulses of
orbital angular momentum required in the protocols are easily realizable with
current technologies.
