On the Possibility of Observing the Effect of Quantization of the Orbital Momentum, during the Passage of Laser Radiation through an Optical Fiber

The speed of propagation of optical radiation in an optical fiber is noticeably lower than the speed of light in vacuum. This fact opens the possibility to consider the propagation of light in fiber in the so-called comoving frame of reference. This type of consideration proved to be very useful and helping, for example, in studying the motion of ultrarelativistic charged particles and gamma rays in ordered media (channeling effect). This type of consideration makes it possible to notice some simple, albeit rather unexpected, macroscopic quantum effects that can manifest themselves when laser radiation passes through optical fibers. In particular, when photons propagate along an optical fiber twisted into a helix, at certain parameters of the helix, the effect of quantization of the moment of the photon momentum should reveal itself. Attracting attention to the possibility of such an effect is the goal of this note, which contains the formulation of the conditions and estimates of the parameters under which the effect of quantization of the angular momentum of photons moving along a spiral trajectory should be observed.