Abstract

Modulational instability (MI) is a general feature of wave propagation in nonlinear dispersive media and has been studied in such diverse fields as fluid dynamics, nonlinear optics, and plasma physics.^1,2 It refers to a process in which weak perturbations from the steady state grow exponentially as a result of an interplay between nonlinearity (self phase modulation) and group velocity dispersion (GVD). In optical fibers, MI is responsible for the break-up into solitons^3,4 of cw optical excitation. In 1980, Hasegawa and Brinkman proposed a new coherent infrared source by means of MI, in which a coherent signal is generated by extracting the sideband of the MI spectrum.⁵ Tai et. al. have recently reported observation of this phenomenon.⁶

© 1989 Optical Society of America