Edilson Camargo

2D Photonic crystal thermo-optic switch based on AlGaAs/GaAs epitaxial structure

The realisation of a thermo-optically controlled symmetric Mach- Zehnder interferometer switch based on an AlGaAs/GaAs epitaxial waveguide structure operating at wavelengths in the region of lambda = 1550 nm is reported. The device is based on a very compact two-dimensional photonic crystal channel waveguide structure. The measured and simulated transmission spectra for the devices are in good agreement. The Pi-phase shift switching power for the device is as low as 42 mW.

Photonic crystal and photonic wire nano-photonics based on silicon-on-insulator

Silicon-on-insulator (SOI) is a strong candidate for application in future planar waveguide integration technology, whether or not luminescence is extracted from the silicon. We review recent research on photonic devices based on silicon-on-insulator. These devices exploit either photonic crystal or photonic wire concepts—or combinations of both. Aspects of the technologies used that are particularly critical for successful implementation of SOI-based photonics are addressed.

Highly compact asymmetric Mach-Zehnder device based on channel guides in a two-dimensional photonic crystal.

We have designed and fabricated a 2D photonic crystal (PhC) asymmetric Mach-Zehnder (M-Z) device structure using W1 channel waveguides oriented along ?K directions in silicon-on-insulator material. The asymmetric structure was designed using a PhC lattice with different filling factors. The asymmetry is obtained as a difference of two periods in the physical path length (DL=2a) between the arms, and it was sufficient to produce a pi phase shift in the region of operation around lambda=1500 nm. The asymmetric M-Z structure is more sensitive than a symmetric M-Z structure to changes in the refractive index and therefore becomes an interesting platform for switching and sensor devices.

Photonic crystal waveguide Mach-Zehnder structures for thermo-optic switching

This paper highlights photonic crystal Mach-Zehnder structures that use W1 channel waveguide in 2D hexagonal photonic crystal structures and have channel orientation along GammaK directions. The FDTD software, Fullwave, from RSoft has been used to simulate photonic crystal channel waveguides, Y-junction and bend in order to design a complete Mach-Zehnder interferometer structure in epitaxial II-V semiconductor material for operation at 1550nm. It is our near-future aim to use these Mach-Zehnder structures as the basis for thermo-optic switching devices. Electro-Beam lithography (EBL) and reactive ion etching (dry-etching) processes have been used to fabricate these devices

Efficient transmission of 60/spl deg/ photonic-crystal bend by waveguide width tuning

Summary form only given. Photonic crystal (PhC) channel waveguides formed as single or multiple line defects have been investigated and, in the case of a lattice of air holes perforating a dielectric slab, even the single line defect PhC channel waveguides are multimoded. One method to tackle the problem in the case of waveguides with dielectric lateral confinement is to use low-Q cavity resonant effects as they have been shown to improve the performance of the junction(s). Our approach is targeted towards tuning the waveguide width at the region of the bend, because in this case, the modes of interest can be pushed closer to the mid-gap frequency. A two-dimensional finite-difference-time-domain (FDTD) tool is used in order to analyse the dependence of the transmission of the bend on the offset shift.

Photonic crystal and photonic wire device structures

Photonic devices that exploit photonic crystal (PhC) principles in a planar environment continue to provide a fertile field of research. 2D PhC based channel waveguides can provide both strong confinement and controlled dispersion behaviour. In conjunction with, for instance, various electro-optic, thermo-optic and other effects, a range of device functionality is accessible in very compact PhC channel-guide devices that offer the potential for high-density integration. Low enough propagation losses are now being obtained with photonic crystal channel-guide structures that their use in real applications has become plausible. Photonic wires (PhWs) can also provide strong confinement and low propagation losses. Bragg-gratings imposed on photonic wires can provide dispersion and frequency selection in device structures that are intrinsically simpler than 2D PhC channel guides--and can compete with them under realistic conditions.

Photonic crystal planar waveguide devices exploiting the thermo-optic effect

Photonic crystal devices are now being produced for a variety of functions-and the need to provide thermal control of the behaviour suggests the use of thermo-optic effects. It has emerged that thermo-optic effects can provide useful modulation, switching and tuning capability. Future trends indicate fast, low-power, thermo-optically operated photonic crystal and photonic wire devices-and the possibility of simultaneous athermal characteristics.

2D photonic crystal four-port directional coupler

We have fabricated and measured a four-port coupled channel-guide device using W1 channel-waveguides oriented along-/spl Gamma/K directions in a two-dimensional (2D) hole-based planar photonic-crystal fabricated in silicon-on-insulator (SOI) material, with operation at wavelengths around 1550 nm.

Semiconductor-based active and passive nanophotonics

Nano-structured semiconductors will play a vital role in future photonics, providing efficient localised photon generation and various other functions for communications, sensing, imaging and display applications. We shall provide several illustrative examples of possibilities.

Photonic crystal channel guide Y-junction beam splitter based on an AlGaAs/GaAs epitaxial structure

We report an experimental realization of a PhC beam-splitter operating at 1.5 um. The device structure integrates bends and a Y-junction - and uses different PhC filling factors to enhance the single-mode transmission band.