Dispersion minimization in dielectric waveguides.

TLDR: It is shown that two different solutions are possible for designing guides that give a minimum of distortion due to dispersion, and that a dispersionless group index is possible for wavelengths at least as short as 0.77 micro.

Abstract: The effect of dielectric dispersion on pulse transmission through singly clad, cylindrical fibers is formulated in terms of the effective group index for the waveguide. It is shown that two different solutions are possible for designing guides that give a minimum of distortion due to dispersion. One solution uses fibers with low numerical aperture made from glasses with low dispersion; here for sufficiently long wavelengths minimum distortion is possible while the guide parameters limit conduction to the lowest order mode. It is predicted, for example, that a pulse of radiation in the lowest order mode with a carrier wavelength of 1.06 μ can be conducted with minimum distortion by a fiber made from commercially available, low dispersion glass. In the other solution the fiber is designed so that the HE11 mode provides an anomalous dispersive characteristic; this solution requires a high numerical aperture fiber with a core large enough to support the next higher order group of modes, namely the TE01, TM01, and HE21 modes. For this second solution, it is shown that a dispersionless group index is possible for wavelengths at least as short as 0.77 μ.