Analysis of integrated optical waveguide mirrors

A new method is presented to analyze reflection losses of integrated mirrors, taking into account the exact guided mode profile and assuming that this profile remains unchanged up to the reflecting plane. The fraction of the reflected light coupled to one of the guided modes of the output waveguide is calculated, taking into account the mirror reflection coefficient. The influence of both translation and tilt of the reflecting plane is investigated. The method applies for every guided mode and any reflection angles. Numerical calculations are derived for a 90° optical corner mirror     

Numerical simulation of a silicon-on-insulator waveguideFabry-Perot interferometer for intensity light modulators at 1.3 μm

We present a new silicon-on-insulator (SOI) integrated optics structure to be used as an intensity light modulator at 1.3 μm. The device consists of a waveguide Fabry-Perot interferometer. In association with a grating coupler this device could function as a spatial light modulator or a reflective-mode modulator. The Fabry-Perot reflectivity is tuned by free-carrier injection from a forward-biased lateral P⁺/N^-/N⁺ diode. Consequently, the reflected back guided-mode has an intensity that is a function of the effective index modulation in the central waveguide of the Fabry-Perot. Our numerical simulation reveals that such a structure could function for current densities not exceeding 500 A/cm² with a cutoff frequency of 100 MHz. This new type of device is compatible with the mature silicon technology and could replace in applications the standard liquid-crystal spatial light modulators or for fiber-to-the-home intensity modulators     

Simple technique for fabricating limited coupler gratings byholographic method using standard thick photoresist

The fabrication of photoresist gratings is considered. A solution to the problem of `transversal standing waves' is given and appears simple and versatile     

Diffraction effects in guided photonic band gap structure

The concept of the photonic band gap (PBG) structures stems from ideas of Yablonovitch. The idea is to design components so that they affect the properties of photons, in much the same way that ordinary semiconductor crystals affect the properties of electrons. In fact, the PBG structures forbid propagation of photons for a particular range of energy. They can be used to realise optical filters with large stop band and sharp transmission resonance. In the guided PBG structures, the existence of diffractive effects in the vertical dimension could limit the quality factor of such filters. In this paper, we have investigated the origin of diffraction losses in one-dimensional guided PGB structures using 2D and 3D numerical tools. We propose an analytical approach based on Bragg diffraction relation to explain these losses phenomenon. From this approach, the influence of some design parameters on the electromagnetic behaviour and the spectral response of PBG resonators will be explained.     

Evidence of Bloch wave propagation within photonic crystal waveguides

We report in this paper results obtained from characterizations of photonic band gap waveguide, using near field optical microscopy. We will show evidence of a Bloch wave propagating within our W1 photonic crystal waveguides (PCWs) structure, using a 2D Fourier transform approach. The processed image will then be compared to simulations obtained from plane wave method. This comparison exhibits that near-field measurements, using tapered optical fibers as probes, are mainly sensitive to the electric field propagating within the structure. PACS 42.25.-p; 42.30.Va; 42.770.-Qs; 42.82.-Et     

Slow Bloch surface wave devices on porous silicon for sensing applications

A new type of biosensor using slow Bloch surface waves in photonic devices based on porous silicon is presented. After optimization of the devices, a theoretical performance study is performed and demonstrates an increase in sensitivity by a factor 10 compared to surface wave sensors based on porous-silicon multilayers. First results of the experimental realization of the sensor are also shown.     

Low-loss submicrometer silicon-on-insulator rib waveguides and corner mirrors

Rib microwaveguides are demonstrated on silicon-on-insulator substrates with Si film thickness of either 380 or 200 nm and a width of 1 microm. Corner mirrors that allow compact 90 degrees turns between two perpendicular waveguides are characterized. Measured propagation losses are approximately 0.4 dB/cm and approximately 0.5 dB/cm for 380-nm and 200-nm Si film, respectively, and mirror losses are approximately 1 dB. This allows the development of applications such as optical interconnects in integrated circuits over propagation distances larger than several centimeters.