Directly using sunlight for the illumination of rooms that have no windows is a very important measure for
higher energy efficiency and CO2 reduction in the next future, especially for countries along the sunny belt. The Sollektor
®, developed at the Polymer Optical Fiber Application Center in Nuernberg, Germany, offers an efficient way to do
that. The Sollektor is a combination of a plastic injection moulded concentrator optics array, a control unit which tracks
the sun over the day and a polymer optical fiber bundle, guiding the collected light into the rooms. In order to ensure the
illumination even at times without sun we present concepts and first results for the combination with conventional LED
in order to obtain a 24 hillumination on a high efficiency level with high quality light.
In step-index multimode-fibers, controlled excitation conditions are essential to achieve optimized transmission
properties and control the output beam profile. Especially with lasers as a light-source, selective methods of mode
excitation can be used easily.
So far, fiber properties have been specified using meridional rays (modes), as proposed with the inverse far-field method.
In addition to these meridional rays in step-index fibers, high-order skew rays can be selectively excited. Especially with
excitation angles higher than the numerical aperture of the fiber, these skew rays can propagate with interesting
properties. Based on these extreme test conditions, the core-cladding interface of large-core step-index fibers can be
more efficiently controlled.
POF elongation sensors have been proposed e.g. by  as a low-cost alternative to FBG (single mode fiber Bragg
gratings) sensors targeting the lower sensitivity range. A recently recovered detection system known from laser distance
meters turned out to be very sensitive while staying simple. The approach is based on measuring the phase shift of a
sinusoidally modulated light signal guided in a POF under different tensions resulting in different transit times and thus
different phase shifts.
Polymer optical fiber (POF) elongation sensors have been proposed e.g. by Doering as a low-cost alternative to FBG
(single mode Fiber Bragg Gratings) sensors targeting the lower sensitivity range. A recently recovered detection system
known from laser distance meters turned out to be very sensitive while staying simple and thus offering low cost
potential. The approach is based on measuring the phase shift of a (e.g. sinusoidally) modulated light signal guided in a
POF under different tensions resulting in different transit times and thus different phase shifts.
The concept of highly sensitive fibre optic displacement sensor is presented. It is based on macrobending step index
polymer optical fibre with multiple overlapping surface-side imperfections. The theoretical principles of optical power
losses in such fibres due to multiple curvatures are based on a surface that serves as a model for an imperfect layer and
has the same optical properties. The sensing element was tested using two different types of roughness topologies and
their combination. The various angles of imperfections (90 and 45 degrees) placed on the fibre's core were evaluated.
We discuss some experimental results that confirm our prediction of considerable dependence of the output signal on the
changing imperfections caused by bending the fibre. It was found that sensitivity to bending of the angular imperfections
could be further increased by implementing multiple overlapping imperfections.
Data transmission between rotating and stationary systems, e.g. required for radar antennas or for undersea cable installation ships can be realized with so called rotary joints. For the transmission of several high bit rate optical data channels a micro optical rotary joint is now available which guarantees a dead reliable, low loss transmission for up to 21 parallel single mode channels. The free space transmission in the rotary joint implicates a highly precise collimation of the parallel channels. For this purpose compact two dimensional fiber collimator arrays based on micro lens arrays have been developed. These arrays and the complete opto-mechanical system are designed with the help of tolerance analysis using Monte Carlo simulations. Besides these results also some more information on the behavior and the characteristics of the micro optical rotary joint under real conditions which demonstrate the excellent characteristics of this novel system will be given.
Microstructured Polymer Optical Fibers (MPOF) were first made in 2001, and subsequent development has aimed at exploiting the material and design opportunities they present. Most effort has been focused on developing approaches for high bandwidth MPOF, and investigating the properties of multimode microstructured fibers. We also consider new applications in endoscopy and photonic interconnects, as well as the use of organic dopants in MPOF.
Since more than 2 decades, the polymer optical fiber (POF) based on PMMA is well known. A lot of applications were studied and initiated: in addition to data transmission, the automotive, lighting and sensor applications are of main interest. Due to the spectral attenuation and applications, light-sources like broadband metal-halide lamps and halogen lamps, or LEDs and laser-diodes are mainly used. Due to improvement in manufacturing of the standard step-index POF, the variations of the spectral attenuation in the blue region have been reduced. Therefore, the losses are acceptable for short-length applications in the UV-A region. Using different light-sources like high-power Xenon-lamp, deuterium-lamp or UV-LEDs, the UV-damage is an important factor. In addition to the basic attenuation, the UV-induced losses will be determined by experiment, in the interesting UV-A region. The higher flexibilty of the thick-core POF is superior in comparison to silica or glass fibers with the same outer diameter. Therefore, the bending losses in the UV-region are important, too. For special applications in the medical field, side-illuminating fibers are highly accepted. The axial and spectral dependence on the lateral radiation pattern will be described, using a very thick fiber.
In comparison to standard fibers, fluorescent plastic optical fibers have quite different absorption and emission spectra, especially in the UV-A region up to the NIR-region depending on the co-dopant. These properties can be used for new applications in the field of sensors. In addition to a brief description of the mechanism of light-interaction within the dye-doped core material, an overview is given of the most promising applications.
Polymer Optical Fibers (POF) are the most promising solution for the "last 100 m" ion data communication. The combine the inherent benefits of all optical fibers such as high bandwidth, total electromagnetic immunity with additionally amazing simplicity in handling. This paper will show the evolution of POF for datacom applications, starting from standard step index types via multi-step-index- or multi-core-types to recently published micro-structured POF.
Industrial applications of polymer optical fibers (POF) require a high reliability of the optical data transmission. Therefore it is necessary to investigate the behavior of POF under extreme environmental stressing. For these investigations specific measuring equipment is necessary. The design and practical applications of a multiplexer for optical transmission measurements and of a high-resolution OTDR for damage analysis are described.
This paper presents a passive fiber optic gyroscope without nonreciprocal phase modulation. A fused fiber 3 X 3 directional coupler provides a constant phase shift, thus enabling the detection of rotation rate at the quadrature point. Bias and scale factor errors due to indeterministically changing birefringent coupling centers in the non-polarization preserving monomode fiber coil are eliminated by using a contrast insensitive signal recovery scheme. A simple temperature compensation procedure has been implemented in the gyro software which yields a bias stability < 0.04 deg/sec and scale factor errors < 0.5% in the whole temperature range between -40$DEGC and +70 degree(s)C.