A Appendix

A.1 Group Theoretic Understanding of Optical Fibre Transmission Modes When a light beam propagates in free space or in a transparent homogeneous medium, its transverse intensity profile generally changes. Despite this, there exist certain distributions that do not change intensity profile as they traverse. These fixed profiles are the transmission modes of the space. The development of group equivariant networks exploits a similar principle, where these networks are constructed under the more general principle of finding basis functions called irreducible representations of some group. Thus a function on the group can be composed as a linear combination of the corresponding irreducible representations.