Abstract

Dark spatial solitons can be are launched in bulk semiconductors by using initial conditions with either odd or even symmetry. The odd condition is produced by positioning a glass platelet in one half of the incident 30 ps pulse, so as to produce a π phase shift, and it propagates parallel to the propagation axis. The soliton also narrows with increasing bright background intensity. Such behavior agrees with that theoretically predicted for fundamental dark solitons and is consistent with previous experimental observations of temporal fundamental dark solitons propagating in optical fibers. Nevertheless, such simple tests provide only limited evidence of soliton formation. A far richer experiment, also with an analytic solution in two dimensions, is to launch pairs of dark spatial solitons by using the even initial conditions.¹ For such pairs, several propagation parameters were measured and good agreement with theory was obtained. They are as follows: transverse velocity versus wire width, contrast ratio versus transverse velocity, conservation of the number of dark structures, and soliton constant versus intensity. The observed phenomenon has applications in optical switching and communications.

© 1990 Optical Society of America