Novel optical waveguide beam steering device

Abstract

We present a new optical waveguide beam steering device, consisting of a pair of asynchronous waveguides. The asynchronous operation prevents coupling between the two waveguides but results in a phase delay between them. Using this effect, the output light can be steered in the far field by varying the phase delay. Analyses of the beam steering device shows that the separation between the waveguides should be small, and the light confinement in the two waveguides should be weak, but the waveguides should not be coupled. For these considerations, a device with a steering angle of up to 20°, with side lobe intensities 10 dB below the main lobe was designed. Far field analysis is valid here for distances >100 μm from the end of the device. For uses in all-optical switching, the proposed device geometry consists of AlGaAs multiple quantum well nonlinear waveguide and an AlGaAs linear waveguide. The refractive index of the nonlinear guide is modulated by an external controlling light beam. The induced phase difference between the two waveguiding modes results in the steering of the output light, which is collected by fiber waveguides in the far field.