RESUMO
Efficient post-process suppression is demonstrated of spurious Fabry-Pérot oscillations, introduced by multiple cavity effects in transmission spectra measurements of various Bragg grating devices. These devices were fabricated within access waveguides and terminated with cleaved facets. The tool, based on a curve-fitting to an equivalent scattering matrix model, is shown to extract transmission spectra of devices, without a-priori knowledge of their properties. Simple and complex grating structure spectra are successfully extracted and compare well with simulated results. The technique exhibits robust behaviour for varying facet conditions and device geometries, outperforming classical averaging techniques.
Assuntos
Algoritmos , Interferometria/instrumentação , Dispositivos Ópticos , Oscilometria/instrumentação , Refratometria/instrumentação , Análise Espectral/instrumentação , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Modelos Teóricos , Espalhamento de RadiaçãoRESUMO
Photonic Wire Bragg Gratings, made by periodic insertion of lateral rectangular recesses into photonic wires in silicon-on-insulator, can provide large reflectivity with short device lengths because of their large index contrast. This type of design shows a counter-intuitive behaviour, as we demonstrate - using experimental and numerical data - that it can have low or null reflectance, even for large indentation values. We provide physical insight into this phenomenon by developing a model based on Bloch mode theory, and are able to find an analytical expression for the frequency at which the grating does not sustain the stop-band. Finally we demonstrate that the stop-band closing effect is a general phenomenon that may occur in various types of periodic device that can be modeled as transmission line structures.
Assuntos
Dispositivos Ópticos , Refratometria/instrumentação , Transdutores , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
We report measurements and numerical modeling of spectral broadening and soliton propagation regimes in silicon-on-insulator photonic wire waveguides of 3 to 4 dispersion lengths using 100fs pump pulses. We also present accurate measurements of the group index and dispersion of the photonic wire.