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In the course of claiming more energy efficient buildings it is necessary to reduce the amount of artificial lighting. With the aim of realizing a very thin system integrated into building facades microstructures for the redirection of daylight are developed. In order to achieve sufficient room lighting at night or other situations of less sunshine, this daylighting system is coupled to a system for artificial lighting consisting of a microstructured light guide plate. This system transforms LED point light sources to a planar light source, which lights the room ceiling. The micro structures, its functionality and application are explained.

Microstructured light guiding plates (LGP) open up new capabilities in the design of energy efficient and flexible light sources for room lighting. One desirable application is the illumination of office rooms by LGPs located mainly at the façade. Starting with the requirements of an ideal light distribution curve for uniform room lighting, suitable optical microstructures have been designed and investigated by numerical ray tracing methods to be integrated in façade elements. The maximum of the desired light distribution curve for the test case is at an angle of 96° with respect to the vertical direction. The designed micro-system meets this requirement very well at an angle of 98° and a light cone width of 25°. The light emission of the proposed LGP is highly efficient with 80% coupling efficiency.

This paper presents a non-tracking microstructured light redirecting device, which can be integrated into architectural glass. When fixed in the upper area of a window above eye level it redirects the light from solar altitudes between 15° and 65° and illuminates a room without causing glare. Ray-tracing calculations are employed as a tool for identifying suitable configurations and geometries. The results of the simulations show the advantage of combinations of lens-like with prism-like geometries in comparison to conventional microprism arrays regarding the overall light redirection efficiency as well as the producibility. The redirecting device is more lightweight, gives better integration options and is producible in a more economic manufacturing process as systems with similar performance. Measurements of cast silicone prototypes (100 mm × 100 mm × 4 mm) confirmed the simulation results. By now the performance has also been shown by large scale industrially produced acrylic panels with dimensions of 1500 mm × 400 mm × 4 mm.

In the paper, a packaging technique of polysiloxane based flexible electrical-optical-circuits-board (EOCB) with Kapton (Dupont) foils was developed and introduced. The main mechanism of forming a good bonding between polysiloxane and Kapton foil was identified and verified. The optical and mechanical properties of the polysiloxane waveguide layer remained unchanged before and after packaging. According to the defined procedures, the environmental stability of packaged EOCBs has been tested with the result that they exhibited excellent mechanical, optical, and thermal stabilities. The mechanical stability limit of the tested EOCBs is determined only by the intrinsic mechanical stability of the used polysiloxane materials. The optical waveguide propagation loss at 850nm is less than 0.1dB/cm after surviving from the defined environmental test procedures.

The optical properties of transparent PDMS polymer materials, which can be integrated into general printed circuit board (PCB) for data communication, are of great interest due to the substantial market expectations for the near future. For the present paper, it was found that the absorption loss in polydimethylsiloxane (PDMS) is mainly caused by the vibrational overtone and combination bands of the CH3-groups of the polymer in the spectral datacom region of 600–900 nm. Based on observed positions of fundamental, overtone and combination bands of the methyl-group, as recorded within the mid- and near-infrared spectra, anharmonicity constants and normal vibration frequencies were determined. Thus, an empirical equation for estimating the wavelengths with the most significant intrinsic absorption loss due to the corresponding band positions was formulated, which was found to agree well with the experimental data. In addition, PDMS multimode waveguides were fabricated and the respective optical insertion loss was measured at 850 nm, which is commercially used for optical datacom transmission and finally the thermal stability of PDMS multimode waveguides was verified as well.

LIGA is the basic idea of promising developments for the manufacturing of microelectromechanical system parts containing high aspect ratio microstructures. Aim of the work is a brief discussion of the starting-points for inline process inspection within a direct LIGA technology using deep X-ray lithography for the production of micromechanical gear wheels with critical dimensions of ∼35 μm width at ∼1 mm height as well as to show methodic and technical measuring possibilities. Firstly, results of the determination of residual solvent content distribution within ultra-thick SU-8 films are shown obtained from refracted near field optical measurements. Furthermore, the capability of X-ray computer tomographic imaging is discussed and measurements for the determination of the three-dimensional shape of high aspect ratio microstructures are practically demonstrated with microscopic and interferometric optical methods. Finally, first results demonstrate the potential of the optical coherence tomography for several further important measurement tasks, among others, e.g. for the imaging of the distribution of mechanical stress at the resist–substrate interface. The results show that much information which is essential in the LIGA process can be achieved with recently available measurement methods. However, further development of non-destructive measurement techniques would be desirable for an effective inline process control of mass production of micromechanical parts.

Recent activities in the field of optical detection on microfluidic chips suggest a variety of applications which can hardly be realised without integrated optical elements on chip. We here present a polydimethylsiloxane (PDMS) microfluidic chip with integrated waveguides as a high efficient optical detection system for the wavelength range 400-800nm. The cheap material, the simple fabrication process based on microcasting of polysiloxane and short process times offer the option for a low cost mass production.

Ray-tracing calculations are employed to identify basic design rules for the configuration of microstructured daylighting systems. The results show the advantage of combinations of lenslike geometries in comparison to conventional microprism arrays regarding the overall light redirection efficiency as well as the producibility and cost efficiency. Measurements at silicone prototypes and large scale industrially produced acrylic panels confirmed the simulation results. Optimization leads to free-form geometries which can further be improved by selective roughening of specific microsurfaces.

Here we present an optical transceiver concept for a reflective star bus system, showing favorable properties in respect to coupling efficiency and packaging. It is based on a hot embossed polymer substrate with two integrated micro-mirrors and a waveguide. On top of the substrate, above the mirrors, a vertical-cavity surface-emitting laser diode (VCSEL) and a photodiode chip are mounted with a flip-chip technique. At the end face of the waveguide a Polymer Clad Silica (PCS) fiber with a core diameter of 200 μm is attached in a groove. Thus an easy assembly of the individual components and a compact package is achieved. To evaluate and optimize the efficiency of the transceiver module we performed extended ray tracing calculations. Included are coupling efficiency between fiber and planar waveguide as well as coupling efficiencies between VCSEL and waveguide and between waveguide and photodiode, respectively. For a realistic estimation we took the transverse mode emission behavior of VCSELs at different supply currents and temperatures into account. Therefore we measured far-fields of VCSEL chips mounted on a heat sink for temperatures up to 85 °C and included the results in the simulations. The calculations indicate that the temperature dependant output power of the VCSEL is partly compensated by the variation in coupling efficiency. Measured VCSEL to fiber coupling efficiencies of about 60 % and out-coupling efficiencies to the photodiode of 70 % are achieved, in good agreement with calculations. Therefore our compact and low-cost concept shows at least 2 dB lower insertion losses compared to conventional 3 dB coupler solutions.

For coupling of light into and out of the optical layer in electric-optical printed circuit boards (PCBs) a scheme for a perpendicular coupling of the light with respect to the waveguide layer is presented. The required 90° light deflection is accomplished by integrated silver-coated 45° micro mirrors which are moulded into polymer substrate together with the waveguide grooves. Exact alignment of the optoelectronic modules with respect to the mirrors is obtained by holes in the waveguide layer and MT pins in the OE-modules.

A coupling concept for a self-aligning and passive assembly of optical transmitter and receiver modules to board-integrated multimode waveguides is presented. The coupling mechanism is based on a 90 degree(s) beam deflection provided by micro-mirrors which are part of the board-integrated waveguides. The alignment is obtained by a mechanical high precision interface consisting of alignment pins well known from MT connectors at the module side and corresponding holes which are part of the optical layer. As the production of the alignment holes is part of the manufacturing of the optical layer, the required accuracy can be achieved without noteworthy difficulties.

A 64 channel optical array interconnect based on 125 micrometers polymer optical fibers arranged in an 8 X 8 array with dimensions of 2 X 2 mm 2 is presented. Typical insertion losses of 1.5 dB (660 nm) and 5 dB (980 nm) over 20 cm interconnection length have been measured.

Passive fibre-waveguide coupling is a promising alternative to expensive active coupling in single-mode fibre-optics. The idea to utilize replication techniques in transparent polymeric materials for waveguide and alignment structure fabrication has led to the SIGA-process (Silizium, Galvanik und Abformung) which allows a cost effective production of low loss polymer waveguides in the near IR. Major difficulties in passive fibre coupling are caused by the high lateral alignment accuracy (of about 1 micrometer) in fibre positioning. In the SIGA process, the exact position of the V- grooves relative to the waveguide trenches is defined by the etch mask for the silicon master wafer. The width of the V- grooves is determined by the KOH etching time. It is controlled precisely at various stages in the etching process by means of a microscope based piezo driven measurement system with a resolution better than 0.5 micrometer, thus allowing a final vertical precision of fibre positioning of 350 nm. In order to specify the capability of our technology we have measured the position of dozens of fibres glued into V- grooves. The result was that an amount of 55% of the fibre cores was closer than 1.5 micrometer to the waveguide centre. As the experience has shown, a two-step process for the fabrication of passively fibre coupled waveguides is necessary. First, the waveguides are produced by filling the waveguide trenches with an IR-transparent monomer and by polymerizing it using UV curing. The waveguides are inspected with visible and IR light by clamping a fibre ribbon mechanically into the integrated plastic V-grooves. In a second step the fibre ribbon is fixed irreversibly in the V- grooves. By that way we have reached an insertion loss of 3.5 dB at 1300nm and 1550nm for passively coupled 22mm single mode waveguides. Most of the losses are attributed to waveguide imperfections. More details concerning the coupling losses and the device performances will be reported at the conference.

Single-mode optical waveguide devices with integrated fiber- alignment grooves have been fabricated by injection molding of structured substrates and by subsequent filling of the waveguide channels with higher refractive index polymer. The master forms of the microstructures have been micro-machined channels with higher refractive index polymers. The master forms of the microstructures have been micro-machined in silicon. A special injection molding tool has been developed to yield plastic substrate chips with high surface planarity and replicated microstructures with details in the submicron range. Hot embossing is a further technology applied for the fabrication of large area waveguide devices with integrated mirrors, mainly intended for optical backplane applications. The hot embossing tool is driven on an injection molding machine which is a more cost effective method than the acquisition of conventional hot embossing equipment. In this paper, the injection molding as well as the hot embossing tool will be described together with the process and the results in the field of passive components for optical telecommunications and datacommunications.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Based on the standards for optical components in telecommunications (Telcordia) and general printed circuit boards (Institute of Printed Circuits and International Electro Technical Commission), three environmental stability verification tests are concluded for polysiloxane-based electrical-optical circuit boards (EOCBs). In terms of defined test models, the respective acceleration factors are determined. Combining the acceleration factors and proposed reliability objective of 400 failures in time (FITs) (one FIT is equal to one device failure in 10(9) device hours of operation) at the 90% confidence level, EOCB test sample size to each acceleration test are deduced, and a corresponding amount of samples are prepared for mechanical and optical stabilities verification. In addition to the good mechanical stability the results exhibit, the packaged EOCBs have low and stable optical loss values (0.1 dB/cm) and numerical aperture even at extreme environmental conditions. Furthermore, a total failure rate of 400 FITs is predicted for 14.4 yr of operation at 25 degrees C and moderate humidity conditions (20% relative humidity).

A large area (390/spl times/150 mm) flexible polymer optical waveguide foil and its production process is presented. The waveguide materials are highly transparent, refractive index tuned polysiloxanes. The waveguide layer is embedded between two flexible PCB laminates. The optical loss at 850 nm is

Fabrication of integrated optic polymeric components by moulding waveguide and fibre alignment grooves to a substrate in a one-step process, and subsequently filling the waveguide grooves by means of a microstructured strip-off cover which is later removed, is presented. The latest measurement results on waveguide attenuation, coupling losses owing to passive fibre-waveguide coupling and excess loss values are given.

2×4 optical interconnects are realised by plastic optical fibres which are precisely aligned by means of 2D arrays of holes. Coupling to the emitters and detectors is accomplished by low loss 90° fibre bends. The total insertion loss of a 20 cm long 2×4 interconnect is 2 dB ±0.2 dB at 633 nm, including two 90°-bends.

The refractive index profiles of titanium-diffused LiNbO(3) planar and channel waveguides are determined directly by measuring the reflectivity of angular polished surfaces. Three measurement techniques are described and compared: (1) large area illumination of the angular polished waveguide and imaging of the reflected light to a vidicon, (2) scanning of a focused beam across the sample, and (3) scanning of the sample under a focused beam. Preference is given to the last method which provides an accuracy of Deltan/n = 10(-4) with a local resolution of the index profile of

The reflectivity measurement of angular polished surfaces of Ti:LiNbO3 waveguides is utilized to determine directly the refractive index profiles of planar and stripe waveguides with an accuracy of dn/n = 10 -4 and a local resolution of < 0.1 μm in depth and < 1 μm in width.