ZnO processing for integrated optic sensors

ZnO thin films were sputter deposited onto oxidized silicon wafers. The film quality increased with increasing applied r.f. power. Characterization of the films was performed by measurements of the attenuation of the transverse electric TE0 optical guided mode. For an applied r.f. power of 2000 W, the deposition rate was 220 nm min−1, resulting in a mode attenuation of only 1.6 dB cm−1 for a film 0.8 μm thick.\ud \ud The refractive indices of the films were 99.5% (ordinary index) and 99.8% (extraordinary index) of the single-crystal values.\ud \ud The step coverage on etched SiO2 profiles appeared to be very smooth, which simplifies the creation of waveguiding channels. The optical behaviour of multilayered waveguides consisting of ZnO and SiO2 films was studied. A prototype of a mode coupler in such a multilayer showed the feasibility of efficient electro-optic modulation in ZnO-based waveguides

Simple measuring method for electro-optic coefficients in poled polymer waveguides

A simple measuring technique for the linear electro-optic coefficients in electro-optic waveguides is described. The method is based on the direct evaluation of synchronous angle measurements obtained by prism coupling. No waveguide or electrode patterning is required. A model has been developed in order to simulate the relation between change in synchronous angle and applied electric field across the electro-optic waveguide. The measured values of the electro-optic coefficients in poled polymer waveguides are reported

Novel geometry for second-harmonic generation in poled polymers

Second harmonic generation via counter propagating beams was demonstrated in poled polymer channel waveguides which were efficiently poled by in-plane geometry (d22 equals 153 pm/V). Although applications for high speed signal processing, such as pulse convolution and wavelength division multiplexing, are our primary object, it has competitive potential for frequency doublers against normal co-propagating geometries because of utilization of large resonant nonlinearities

Efficient Second Harmonic Generation In Polymeric Channel Waveguides Using Modal Dispersion

Second harmonic generation (SHG) is getting renewed attention through possible applications to all-optical switching, spatial solitary waves, etc. This work demonstrates efficient SHG over a distance of 0.3 cm with an efficiency of η′ = 0.1%/W. An enhancement is feasible through optimization of the overlap integral. Other possible improvements include an increase of the acceptance bandwidth and a design less sensitive to thickness variations, therefore allowing longer propagation distances

Efficient Second Harmonic Generation In Polymeric Channel Waveguides Using Modal Dispersion

Phase matching with use of modal dispersion typically requires excellent control of the waveguide thickness, but can be easily implemented in low loss configurations, since it does not require any modulation of waveguide parameters along the propagation. This paper demonstrates efficient SHG in a channel waveguide made of DANS (4-dimethylamino-4′-nitrostilbene) side-chain polymer with a figure of merit η = 1.2%/W-cm2 over a phase-matched length of 0.3 cm, which is deemed the best combined values reported for poled polymers to date

Thermally induced reversible easy axis rotations in permalloy thin films

The thermal stability of the easy axis orientation in thin Permalloy films was studied. This orientation was measured by two methods, i.e. the magneto-optic Kerr effect and a novel measurement scheme based on magnetoresistive effects. It appeared that even for small temperature changes rotations of the easy axis occured. Together with the commonly observed irreversible rotations (thermal annealing), reversible rotations were also measured. Variation of film composition, substrate layer and different annealing steps were tried to obtain a better understanding of this unexpected behaviour. No well-defined correlation could be established between the varied parameters and thermal behaviou