We demonstrate efficient photon pair generation for quantum communication using an all-semiconductor approach. In an AlGaAs Bragg-reflection waveguide we employ spontaneous parametric down-conversion to produce photon pairs at telecommunication wavelengths. The various phase-matching solutions present in our device can be used to create timebin or polarization entanglement. This approach can to lead to a fully integrated photon pair source with the pump laser, active and passive optical devices all on a single semiconductor chip.
An overview of recent advances in exact phase matching technologies of second order nonlinear optical processes in
compound semiconductors is reported. The technique used utilizes dispersion engineering in Bragg reflection
waveguides (BRWs) or 1-dimensoinal photonic bandgap structures to achieve phase matching between the interacting
waves. One of its distinguishing features in comparison to other techniques is that it does not involve any demanding
technological steps such as oxidation, nor does it rely on periodic modulation of the optical properties of the materials
used in the propagation direction. This in turn provides phase matching with significantly lower optical losses in
comparison to other techniques. Nonlinear conversion efficiency matching what is achievable in periodically poled
lithium niobate is obtained for ridge BRWs fabricated in GaAs/AlGaAs. Most notable applications that would benefit
from integrable ultrafast second order optical nonlinearities include monolithically integrated optical parametric
oscillators, correlated photon pair sources and monolithic tunable frequency conversion elements.