Semiconductor-Doped Glasses for Nonlinear Integrated Optics

摘要

The properties of all optical switching devices, as applied to nonlinear directional couplers in semiconductor-doped CdSxSe1-x glasses were investigated. This program achieved five distinct goals: 1. The operating characteristics of, and material requirements for, a variety of all-optical switching devices were investigated theoretically and defined for the first time. The device included nonlinear directional couplers, Mach-Zehnder interferometers, and distributed feedback gratings; the nonlinear phase shifts required for device switching operation were found to be 4pi, Approx. equal to 2 pi and pi, respectively. 2. Parameters for forming ion-exchange waveguides in CdSSe-doped glasses and color filter glasses were evaluated. Single-mode channel waveguides and directional couplers were designed, fabricated, and tested in these materials. 3. The nonlinear properties, the intensity-dependent refractive index, and absorption changes and their time evolution in channel waveguides in the semiconductor-doped glasses were evaluated experimentally, using a novel pump-probe hybrid Mach-Zehnder interferometer, and compared with the predictions of plasma theory. The relative contributions of the electronic and thermal nonlinearities were measured. 4. All-optical switching in a nonlinear directional coupler was demonstrated experimentally with a 20-ps turn-off time for the first time. Thirty percent switching was obtained, in excellent agreement with theory. 5. Figures of merit for a series of semiconductor materials were calculated, based on the solid-state properties of the materials. Keywords: Cadmium sulfur selenides. (MJM)