{'fraction_non_alphanumeric': 0.017973856209150325, 'fraction_numerical': 0.0, 'mean_word_length': 4.951456310679611, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Propagation of light in a cylindrical system of tunnel-coupled waveguides

Propagation of light in a cylindrical system of tunnel-coupled waveguides is studied. The waveguide system was constructed by layer-by-layer deposition of waveguides on the inner wall of a reference tube by the SPCVD technique developed for synthesising fibre preforms. It is shown that the waveguide light beam in such a system moves along a helical wave-like trajectory and is partially emitted outside at its 'crests'. The angular dependence of the trajectory period and of the number of oscillations along the trajectory is measured.