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This study is focused on the low temperature plasma enhanced chemical vapor deposition technique used for fabrication of silica based optical waveguides on silicon, utilizing nitrous oxide as an oxidant for both silane and dopant. Fabricated channel waveguide shows total insertion loss of 1.2 dB at 1.55 micrometers , and no absorption peaks associated with N-H and Si-H bonds around 1.5 micrometers have been observed in the as deposited material. This fabrication technology adds flexibility to the monolithic integration of electronic and optical components. Using this technology, a n umber of different couplers based on multimode interference technique have been investigated.

A compact optical correlator based on binary liquid crystal spatial light modulators has been built. The correlator has a 21 X 28 cm2 footprint and can process 256 X 256 pixel images at a maximum frame rate of 220 Hz. The system is insensitive to transportation and can be used both in VLC and JTC configuration. It can process live images from an external camera as well as images from computer memory. Variations of illumination conditions can change the graylevels and perceptible details of a target considerably. When this is the case, classical filters like phase only and optimal trade-off fail to detect the target. An improvement of the results can be achieved by using the optimum generalized filter. In most cases, the contour of the target remains more or less the same even if the graylevels are fluctuating. We show that by edge-enhancing and binarizing the input images used together with the optimum generalized filter we can achieve comparable results as compared to using grayscale images.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Ultra-compact EO polymer modulators based on hybrid plasmonic microring resonators are proposed, simulated and analyzed. Comparing with Si slot microring modulator, hybrid plasmonic microring modulator shows about 6-times enhancement of the figure of merit when the bending radius is around 510 nm, due to its much larger intrinsic quality factor in sub-micron radius range. Influences of the EO polymer height and Si height on the device's performance are analyzed and optimal design is given. When operating with a bias of 3.6 V, the proposed device has optical modulation amplitude of 0.8 and insertion loss of about 1 dB. The estimated power consumption is about 5 fJ/bit at 100 GHz.

This paper reviews some results of an ongoing research program at the Institute of Optical Research that addresses optical correlators dedicated to pattern recognition. A two- class discrimination problem with in-plane distortion is considered. To cope with the loss of information that may occur when input images are directly displayed on experimental binary SLMs in a Vanderlugt correlator, we have implemented several types of preprocessing operators on the original gray scale images. Performance criteria are presented to assess and grade preprocessors that can be implemented in real-time on an electronic frame grabber board. Optical implementation in a VanderLugt correlator is described. Experimental results are provided and emphasize the benefits of preprocessing prior to binarization. Significant improvements are found, both digitally and optically, with classical derivative and rank operators.

This paper presents experimental and simulation results from ongoing research on the influence of clutter on OTSDF filter performance. The degrading influence of overlapping clutter can be reduced by including colored noise in the filter construction or by tuning a white noise filter. Simulation results together with experimental results from a van derLugt correlator indicate that tuning of a white noise filter is the most effective for low levels of clutter in the input images whereas inclusion of colored noise is more effective for high levels of clutter. The experimental results are well in line with the simulations.

This paper reviews the progress of an ongoing research program at the Institute of Optical Research which addresses optical correlators dedicated to pattern recognition. A two-class discrimination problem with in-plane distortion is considered. For this purpose, we provide here a comparison between the performances of several synthetic discriminant function (SDF) filters implemented on a binary ferroelectric liquid crystal spatial light modulator (FLC SLM). While non-constrained optimal trade-off (OT) SDF filters perform very well, binary filters offer lower efficiencies. The relative merits of direct binarization of the complex transmittance of the filter and the Jared-and-Ennis method (relaxation algorithm) for filter construction are discussed. To overcome the poor modulation capability of available SLMs and take full advantage of the tuning ability of OT SDF filters, we propose to encode composite filters as detour-phase holograms. We illustrate this discussion with computer simulations as well as experimental results obtained with our optical VanderLugt correlator. In-plane rotation tolerance over 90 degrees and two-class target discrimination are experimentally achieved with a single composite filter.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Hybrid plasmonic waveguides and directional couplers have been experimentally demonstrated. Using a direct measurement method, the propagation loss of a 170 nm wide waveguide is measured to be 0.08 ...

Techniques for manufacturing of Bragg fiber gratings as well as the sensor system based on in fiber Fabry-Perot interferometers are presented.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Strain measurements on composite materialby using phase stepping moire interferometry.Lech Wosinski, Jean-Pierre Beten&Bon and Bertrand NoharetInstitute of Optical ResearchS-1OO44 Stockholm, SwedenABSTRACTWe describe here a practical implementation of phase stepping moire interferometry fordetermination of a strain field in areas located close to optical fibers embedded in compositematerials. The results show that fibers introduce only a local perturbation without noticeableinfluence on mechanical properties of materials.

We demonstrate a real endoscopic moire metrology by using a fiberscope as an image transmitting system. For grating projection interference fringes from two single-mode fibers were used. The substraction of the projected grating from a reference was provided in real-time and moire fringes could be observed on a live image which is important for medical diagnostic.

In this paper we present an experimental evaluation of a quasi-distributed fiber-optic strain and temperature sensor system based on time division multiplexing. The system relies on an advanced dual-core fiber to which a set of Fabry-Perot interferometers is introduced with fiber Bragg gratings used as weak reflectors.

An optical microcavity based on pillar arrays has been fabricated in Si/SiO(2) material system. Transmission measurement was taken and a quality factor as high as 27,600 was observed. This cavity was tested for sensing applications by immersing into optical fluids with accurate refractive indices. For refractive index change of 0.01, a resonance peak wavelength shift of 3.5 nm was measured. We also compare cavities consisting of pillars with different aspect ratios.

Experimental results are presented for a high quality factor cavity based on pillar arrays. The cavity is formed from a square lattice of silicon pillars of finite height. The quality factor of the fundamental mode is about 7300 when the cavity is in air and 7800 when it is immersed in water. Since a pillar array has a large percent of connected void space and confines TM modes effectively, it has great promise for use in numerous areas including biochemical sensing and quantum cascade lasers.

This paper describes a fiber-optic interferometer which uses two laser diodes in a modified Mach-Zender configuration for testing aspherical surfaces with phase shift technique and a possibility to implement two wavelength technique. Experimental results show that this type of interferometer is very useful for in-process control directly on a diamond turning machine, the test element still attached to the chuck.

A system for phase stabilization of different interferometric set -ups is presented A point sensitive high resolution het-erodyne interferometer is integrated into a full field Twyman -Green interferometer for optical testing. A phase stability of 0.8 mn (rms) is obtained through a piezo feedback controlled by a computer closed loop control. The system is opted for two-wavelength phase -shifting interferometry (TWPSI) where succesive recordings under well defined phase steps is applied.For optical testing with TWPSI one have to record two sets of phase data with two different wavelengths. These are thenused to calculate the phase map corresponding to a longer equivalent wavelength.1. INTRODUCTIONInterferometry has for a long time been used as a very valuable technique for measurements in the microscopic lengthdomain, due to its high sensitivity. With the wavelength of light as a length unit extremely sensitive techniques can be obtained.This is especially true for modem techniques for optical testing using high resolution detection schemes. High phase resolutionis in many cases essential when testing aspherical surfaces due to the large dynamic range such surfaces can involve, if a sphericalnull- compensation technique is used.A requirement to make such measurements possible and meaningful is a stable environment with a low noise level. A

An optical filter based on side coupling between silicon wire waveguide and two-dimensional photonic crystal surface-mode cavity is presented. The design is optimized numerically by parallel three- ...

Negatively and positively refractive behaviors are achieved in a two-dimensional photonic crystal of pillar type for TE and TM polarizations, respectively, at the same frequency. The photonic cry ...

A novel layout for an ultra-compact arrayed-waveguide grating (AWG) demultiplexer is presented. The present layout has two overlapped free propagation regions, and is more compact than a conventional layout. Using αSi-on-SiO2 nanowire waveguides, an ultra-small 4×4 AWG (about 40×50 µm2) with channel spacing of 11 nm is fabricated and characterised.

Complete birefringence compensation is demonstrated in plasma-enhanced chemical vapor deposition waveguides by 193-nm postexposure. A single relaxation process dominates the decay in stress anisotropy, indicating that compressive stress from the substrate leads to an elastic stress anisotropy at the core.

We present a portable, versatile optical pattern recognition system that can process 256x256 pixel images at high speed. The system is fully controlled by Windows-based software and can easily be switched between VanderLugt and joint transform operation. It combines the advantages of optics and electronics to form an advanced hybrid system where pre- and postprocessing algorithms can be varied depending on the application. Simulation and experimental results show that edge enhancement combined with binarization gives good results when applied to images where the illumination is varying.

A null test method for testing aspheric optical surfaces based on geometric considerations of conic sections is presented. The basic principles have been investigated experimentally by designing and building a modified Mach-Zehnder interferometer. By using optical fibers the inconvenience of alignment has partly been overcome. Phase shifting has been implemented and the measurements are performed with the help of a microcomputer. The performance of the interferometer has been investigated by testing an elliptical toroid mirror. Further improvement of the test procedure by Zernike polynomial decomposition is discussed and performed. Finally, an even more compact conic section interferometer is proposed.

A novel hybrid plasmonic waveguide with nano-scale confinement, consisting of a metal layer separated from a SOI nano-rib by a thin silica layer has been realized. The loss of 0.01dB/µm allows for ultra-high density photonic integration.

Characteristic analyses are given for a bent silicon hybrid plasmonic waveguide, which has the ability of submicron bending (e.g., R = 500 nm) even when operating at the infrared wavelength range (1.2 μm~2 μm). A silicon hybrid plasmonic submicron-donut resonator is then presented by utilizing the sharp-bending ability of the hybrid plasmonic waveguide. In order to enable long-distance optical interconnects, a pure dielectric access waveguide is introduced for the present hybrid plasmonic submicron-donut resonator by utilizing the evanescent coupling between this pure dielectric waveguide and the submicron hybrid plasmonic resonator. Since the hybrid plasmonic waveguide has a relatively low intrinsic loss, the theoretical intrinsic Q-value is up to 2000 even when the bending radius is reduced to 800 nm. By using a three-dimensional finite-difference time-domain (FDTD) method, the spectral response of hybrid plasmonic submicron-donut resonators with a bending radius of 800 nm is simulated. The critical coupling of the resonance at around 1423 nm is achieved by choosing a 80 nm-wide gap between the access waveguide and the resonator. The corresponding loaded Q-value of the submicron-donut resonator is about 220.

AC electric poling introduces in P3HT nanofibers anisotropic electro-optical response and birefringence. Along with birefringence, such material exhibits strong amplitude modulation which makes it more efficient alternative to liquid crystals.

Design, fabrication, and characterization of an optical filter based on side coupling between silicon wire waveguide and photonic crystal surface mode cavity in silicon on silica structure is presented for the 1550 nm wavelength spectral region.

The strong difference between the dispersion of a Bragg reflection waveguide and a channel waveguide is used to create a narrow band coupler. The principle of operation is confirmed with experimental results showing 0.8nm bandwidth for a 2.2mm long coupler.