The excitation of both bright and dark microwave magnetic envelope solitons
has been realized for one and the same resonant ring containing a yttrium-
iron-garnet film magnetostatic wave (MSW) delay line. The resonant ring mod
ifies the MSW character to produce a series of frequency intervals with alt
ernating regions of positive and negative dispersion. These alternating reg
ions support bright and dark soliton production, respectively. (C) 1999 Ame
rican Institute of Physics. [S0003-6951(99)02228-7].