In theory, no more than 80% of the light diffracted by a circular aperture can be directly coupled into one mode of an ordinary optical fiber. To improve coupling efficiency, and illustrate an inverse method for designing optical fibers with a desired mode shape, we have made an optical fiber that guides an approximate Airy pattern as one of its modes. The fiber’s attenuation was 11.0 dB/km at a 1550 nm wavelength, the match between the fiber’s mode and the ideal infinite Airy pattern was 93.7%, and the far field resembled a top-hat beam. The guidance mechanism has strong similarities to photonic bandgap guidance.
Birks, T. (Creator), Gris Sanchez, I. (Creator) & van Ras, D. (Creator), University of Bath, 2016