  In neuroscience, it is of interest to consider all possible modes of
information transfer between neurons in order to fully understand processing in
the brain. It has been suggested that photonic communication may be possible
along axonal connections, especially through the myelin sheath as a waveguide,
due to its high refractive index. There is already a good deal of theoretical
and experimental evidence for light guidance in the myelin sheath; however, the
question of how the polarization of light is transmitted remains largely
unexplored. It is presently unclear whether polarization-encoded information
could be preserved within the myelin sheath. We simulate guided mode
propagation through a myelinated axon structure with multiple Ranvier nodes.
This allows both to observe polarization change and to test the assumption of
exponentiated transmission loss through multiple Ranvier nodes for guided light
in myelin sheath waveguides. We find that the polarization can be well
preserved through multiple nodes and that transmission losses through multiple
nodes are approximately multiplicative. These results provide an important
context for the hypothesis of neural information transmission facilitated by
biophotons, strengthening the possibility of both classical and quantum
photonic communication within the brain.
