Ultrafast All-Optical Switching in an A1GaAs X-Junction,
Abstract
Several recent experiments have verified the existence of relatively large refractive nonlinearities in the region of half the band gap of AlGaAs and GaAs/AlGaAs quantum well structures. Working in this wavelength region has several advantages; it minimizes the effects of two-photon absorption (TPA), which has limited the usefulness of previous devices, it gives rise to devices with very low linear loss and hence high throughput, finally, it also allows the material to be chosen so that the operating wavelength is in the low-loss, 1.55 micrometers, telecommunications window. We have previously reported ultrafast all-optical switching in Al0.18Ga0.82As directional couplers. These devices use the nonlinear refractive index change to break the coupling between two modes and hence change the relative output states of the device. The nonlinear switching characteristics of the directional coupler are a relatively broad function of input power and may not be the optimum for a practical device. Recent theoretical investigations have predicted all-optical switching in nonlinear X-junctions as a consequence of symmetry breaking. The switching characteristics of such devices show the potentially useful feature of a digital-like response. In this paper we report the first experimental observation of ultrafast, all-optical switching in nonlinear X-junctions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1992
- Accession Number
- ADP008221
Entities
People
- A. Villeneuve
- G. I. Stegeman
- J. S. Aitchison
Organizations
- University of Glasgow