9310567 Islam The possibility and properties of solitons in semiconductor wave guides will be studied theoretically and experimentally. Solitons arise in optical fibers due to the balance between group-velocity dispersion and the nonlinearity, and they are interesting because they are self-trapped, robust pulses that act in many ways like particles or fundamental data bits. Just as solitons are valuable for long distance telecommunications and all optical switching in fibers, solitons in semiconductors will be important for integrated optics and compact, integrable, all-optical switches. Using solitons in integrated optics can obviate the need for low-dispersion strip-line structures, which are being studied for short pulse propagation. Recently, major advances have been made in ultrafast switching and networks using solitons in optical fibers. Two approaches will be pursued to demonstrate semiconductor solitons. First, semiconductor waveguides will be used below half of the energy gap to avoid effects from two-photon absorption. The nonlinearity below half-gap will be balanced by the dispersion from a periodic, corrugated surface, producing so-called "gap solitons". In a second approach, the nonlinearity can be enhanced by nearly three orders-of-magnitude by using a resonant nonlinearity at the transparency point in a semiconductor amplifier. Calculations show the feasibility of demonstrating a soliton by balancing the resonant nonlinearity with the material group-velocity dispersion near band gap, and current injection is used to counter both linear and nonlinear absorption. ***
