Joanna Jannson

Temporal self-imaging effect in single-mode fibers

The transfer of information in fibers with a large dispersion of the first order is accomplished by a temporal analog of the self-imaging effect. The simulation of signal propagation in a single-mode fiber is considered by using the analogous Fresnel diffraction experiment.

SINGLE-MODE POLYMER WAVEGUIDE MODULATOR

We report herein the first single‐mode polymer waveguide modulator which can be formed on any surface regardless of its conductivity and refractive index. These include semiconductor, conductor, and insulator surfaces. The tunability of the refractive index of the polymer film allows us to shift the guiding layer from a stepped index profile to a graded index profile. The phase‐matching condition for optical power transfer is achieved through current‐induced index modulation. Thirty‐six dB extinction ratio, which includes 3 dB absorption loss and 33 dB phase‐matched cross coupling, was observed with a current injection density of ∼1.8 μA/μm2. Unlike the conventional symmetrical dual channel coupler, the disparity of the collinear waveguide pair provides us with a much larger dynamic range of waveguide dimension suitable for generating the required phase‐matching condition and thus easing the requirement of waveguide fabrication.

Spatial coherence discrimination in scattering

Expressions are derived, valid within the accuracy of the first Born approximation, for the cross-spectral density and for the spectral intensity of the field that is produced by scattering of radiation of any state of spatial coherence. The results are illustrated by examples that show quantitatively the difference between scattering of laser light and of ambient light. It is suggested that the dependence of the scattered intensity on the degree of spatial coherence of the incident radiation could be utilized to make devices that would discriminate between a laser beam and diffuse light.

45-cm long compression-molded polymer-based optical bus

We report the formation of an optical bus using compression‐molding technique. The linear dimension of such a waveguide is well beyond that of a microlithographically defined waveguide. Theoretical calculation based on the effective index method was used to determine the optimal dimension of the molding tool design for single‐ and multimode waveguides. A molded photolime gel‐based polymer optical bus with a linear dimension of 45 cm was fabricated and then tested at 0.6328‐μm wavelength. Waveguide propagation loss from 0.5 to 2 dB/cm was determined using the two prism method. As a result of this long interconnection distance, board‐to‐board optical interconnects through backplane can be realized using the technology.

Tunable holographic Fabry–Perot étalon fabricated from poor-quality glass substrates

A novel holographic recording method has been demonstrated for fabricating highly reflectant mirror coatings on a glass substrate of poor surface quality. Electro-optically tunable characteristic fringes of a high-finesse Fabry-Perot étalon have been observed from a cavity consisting of a thin nematic liquid-crystal layer and coated with holographic mirrors. Good agreement has been found between measured values and values predicted by coupledwave theory.

High-Efficiency Bragg Holograms In The IR, Visible, UV And XUV Spectral Region

This paper presents a review of high-efficiency Bragg holography at Physical Optics Corporation (POC). Various commercial and space applications of high-efficiency Bragg holographyTmare presented including IR mirrors (or holowindows for solar control), VLSI Holoplanar interconnects (in near IR region), holographic notch filters (IR, Visible and UV), UV/Visible/IR Lippmann holographic mirrors and HOEs, and XUV holographic mirrors and HOEs for soft X-ray laser optics.

Solar Control Tunable Lippmann Holowindows

Tunable Lippmann Holowindows have been developed by NTS as a particular application for Broad-Band Lippmann Holograms investigated within Super High Efficiency (SHE) Holographic Technology. Those holograms can be tuned to be highly reflective (above 99%) in any part of the near UV, Visible and near IR. In particular, they can reflect all direct solar heat radiation and additionally, the near UV part of the solar spectrum that cannot be blocked by glass or acrylic. Additionally, they can be combined with conductive adhesives to create ideal cooling mirrors, with parameters much better than those of existing products. Therefore, they can create a new generation of high efficiency solar heat control windows whose rejection of adjusted parts of the solar spectrum still preserve high visible transmission (up to 87% for single glazing), and the near perfect (close to 100%) reflection of IR direct solar component. In the case of Tunable Lippmann Holowindows, it is possible to adjust independently the U-value, emittance and shading coefficient by the number of glazings, conductive adhesive thickness and hologram reflection, respectively. In other words, SHE Holographic Technology introduces to heat mirror engineering a new degree of freedom - separate near IR reflection coefficient.

Bragg Holograms And Concentrator Optics

NTS Super-High Efficiency (SHE) Holographic Technology consists of Dichromated Gelatin (DCG) Bragg Reflection Holograms possessing properties that maximum hologram diffraction efficiency (reflection, in good approximation) is close to 99.7% and optical scattering/ absorption losses are below 0.2%. Hence, NTS Reflection Holograms can achieve close to the theoretical limit for several important holographic applications, including dichroic/ polychroic mirrors, high-reflection spectrum-selective filters, spectrum-splitting PV/TPV holoconcentrators, large holographic mirrors for space applications, holographic heads-up displays, holographic fiber couplers, holographic optical elements (HOEs) holographic coders/decoders, holographic window films, holographic chromatic filters, etc. In this paper, we discussed the application of SHE Holographic Technology to concentrator optics including especially solar applications.

Analogue of the van Cittert-Zernike theorem for statistically homogeneous wave fields.

A theorem is presented that expresses a correspondence between the degree of spatial coherence of statistically homogeneous fields and the complex amplitude in certain monochromatic fields. The theorem is illustrated by an example that shows the behavior of the degree of spatial coherence of certain partially coherent fields throughout a three-dimensional volume region.

Prism coupling selectivity in anisotropic uniaxial waveguide

General coupling equations are derived describing field amplitude transfer from a prism to an anisotropic, uniaxial waveguide, having its optical axis in the plane of incidence. The influence of optical axis orientation on coupling efficiency and selectivity is discussed for a Gaussian incident beam.