This interesting effect is exactly what we studied in detail in our latest publication in APL Photonics termed “Talbot interference of whispering gallery modes”. We were able to not only show that so-called whispering gallery modes are needed to observe the self-imaging along the angular coordinates in standard step-index multi-mode fibers, but we also demonstrated that it is a super compact way to realize a higher-order beam splitter.
For more details, you can check it out here.
Congratulations to all, but especially to Matias for his great effort!