Notes on Evanescent Wave Bragg-Reflection Waveguides

We investigate an extended version of the Bragg reflection waveguide (BRW) with air gaps as one of the layers. This design has the potential of drastically simplifying the epitaxial structure for integrated nonlinear optical elements at the expense of more complicated structuring. This approach would afford much more flexibility for designing and varying BRW structures. Here, we discuss an extension of the established theory for BRW slabs and report our results of applying Marcatili's method for rectangular waveguides to the BRW case. With this analytic approach we can estimate the effective index of the modes orders of magnitudes faster than with full numerical techniques such as finite-difference time-domain (FDTD) or finite elements. Initial results are mixed; while phase-matched designs have been found, they currently have no significant advantage over other schemes.Comment: 5 pages, 2 figure

Photonic Entanglement for Fundamental Tests and Quantum Communication

Entanglement is at the heart of fundamental tests of quantum mechanics like tests of Bell-inequalities and, as discovered lately, of quantum computation and communication. Their technological advance made entangled photons play an outstanding role in entanglement physics. We give a generalized concept of qubit entanglement and review the state of the art of photonic experiments.Comment: 54 pages, 33 figures. Review article submitted to QIC (Rinton

Parametric down-conversion in photonic crystal waveguides

Photonic crystals create dramatic new possibilities for nonlinear optics. Line defects are shown to support modes suitable for the production of pairs of photons by the material's second order nonlinearity even if the phase-matching conditions cannot be satisfied in the bulk. These structures offer the flexibility to achieve specific dispersion characteristics and potentially very high brightness. In this work, two phase matching schemes are identified and analyzed regarding their dispersive properties.Comment: Due to a miscommunication the unrevised version of this paper was published instead of this one. v2 has quite some modifications and corrections. 7 pages, 4 figure