A photolytic iodine laser is shown to have a 13.59-GHz modulation in t
he laser radiation when simultaneous lasing of two hyperfine transitio
ns is obtained, The necessary gain tuning required to achieve dual-lin
e lasing is accomplished through the use of a magnetic field. In addit
ion, we investigate the possibility of using a nonlinear mirror to inc
rease the gain coupling between the two transitions.