Mr. Uwe Hollenbach Profile

Uwe Hollenbach

at Karlsruher Institut für Technologie

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Author

Publications (8)

Proceedings Article | 2 May 2014 Paper

Three-dimensional buried polymer waveguides via femtosecond direct laser writing with two-photon absorption

Duc H. H. Nguyen, Kerstin Kaleta, Stefan Hengsbach, Ute Ostrzinski, Karl Pfeiffer, Uwe Hollenbach, Jürgen Mohr

Proc. SPIE. 9130, Micro-Optics 2014

KEYWORDS: Refractive index, Femtosecond phenomena, Waveguides, Cladding, Polymers, Diffusion, Integrated optics, Neodymium, Multiphoton lithography, Absorption

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Integrated optics has emerged as a promising solution to the electronic interconnect bottleneck, enabling high bandwidth density and low power consumption. Recently, confining photochemical and physical reactions in a micro-volume has given an extra dimension to optical interconnection using glass or polymer. Three-dimensional waveguides can then connect, combine, or split the optical signal among any blocks in all dimensions. However, the refractive index increase is still a challenge to fabricate free-form, stable and single-mode three-dimensional buried waveguides.

This paper presents a new concept to tackle this challenge using the combination of femtosecond direct laser writing (FsDLW) in polymer and external diffusion of a gaseous monomer. FsDLW with two-photon absorption was used to initiate cross-linking following a programmed trajectory to form the waveguide core. A thermal treatment was then needed to complete cross-linking. Afterwards, a low-index monomer from a gas atmosphere was diffused into the uncross-linked cladding. Since this diffusion hardly occurred in the already cross-linked pattern, the subsequent UV flood exposure only cross-linked the diffused monomer with host oligomer in the cladding. This low-index monomer decreased the refractive index of the cladding and, therefore, created enough refractive index contrast for total internal reflection. Finally, the whole structure was hard-baked for polymerization and stabilization.

The peak refractive index change of 0.012 was revealed using refractive near field method. Measured near-field intensity at the end facet of waveguides showed single-mode Gaussian profiles. We further demonstrated how feature sizes can be linearly adjusted in the range of 5-12 μm by varying scanning speed and laser intensity. Moreover, changing the voxel shape by a field aperture in front of the objective was investigated. Our fabrication method requires only one layer of a single material without masks, contact or wet processing. Free-form waveguides with high index contrast have high potential to improve the density and flexibility of optical interconnects at board level. Some applications of this concept are three-dimensional arrays of optical waveguide network routers, optofans, pitch converters or splitters.

Proceedings Article | 10 May 2012 Paper

Low-loss single mode light waveguides in polymer

Heinrich Sieber, Hans-Jürgen Boehm, Uwe Hollenbach, Jürgen Mohr, Ute Ostrzinski, Karl Pfeiffer, Marcin Szczurowski, Waclaw Urbanczyk

Proc. SPIE. 8431, Silicon Photonics and Photonic Integrated Circuits III

KEYWORDS: Refractive index, Waveguides, Polarization, Cladding, Signal attenuation, Polymers, Near field, Wave propagation, Near field optics, Polymer multimode waveguides

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Proceedings Article | 13 May 2010 Paper

Active modular microsystems based on Mach-Zehnder interferometers

Sven Schuele, Stefan Hengsbach, Uwe Hollenbach, Jingshi Li, Jürg Leuthold, Juergen Mohr

Proc. SPIE. 7716, Micro-Optics 2010

KEYWORDS: Optical components, Prisms, Beam splitters, Interferometers, Glasses, Interfaces, Photodiodes, Microactuators, Optical alignment, Phase shifts

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Proceedings Article | 15 May 2008 Paper

Single mode field analysis and adjustment on polymer waveguides understanding the reasons for coupling losses

Uwe Hollenbach, Hans-Jürgen Boehm, Jürgen Mohr, K. Pfeiffer

Proc. SPIE. 6992, Micro-Optics 2008

KEYWORDS: Refractive index, Channel waveguides, Polymethylmethacrylate, Deep ultraviolet, Waveguides, Polymers, Single mode fibers, Epoxies, Beam propagation method, Polymer multimode waveguides

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Proceedings Article | 14 May 2008 Paper

Modular integration of microactuators and micro-optical benches

S. Schüle, U. Hollenbach, J. Mohr, J. Li, P. Vorreau, A. Efremov, J. Leuthold, S. Schonhardt

Proc. SPIE. 6992, Micro-Optics 2008

KEYWORDS: GRIN lenses, Optical components, Prisms, Beam splitters, Polarization, Interferometers, Coating, Microactuators, Computer aided design, Optics manufacturing

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Proceedings Article | 16 May 2007 Paper

Measurements and modeling of birefringence in PMMA channel waveguides inscribed with DUV radiation

Grzegorz Golojuch, Uwe Hollenbach, Timo Mappes, Jürgen Mohr, Adam Urbanczyk, Waclaw Urbanczyk

Proc. SPIE. 6585, Optical Sensing Technology and Applications

KEYWORDS: Refractive index, Channel waveguides, Polymethylmethacrylate, Deep ultraviolet, Waveguides, Polarization, Birefringence, Polymers, Numerical analysis, Phase shifts

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Proceedings Article | 8 September 2004 Paper

Polymer technologies: a way to low-cost optical components and systems

Jurgen Mohr, Uwe Hollenbach, Arndt Last, Ulrike Wallrabe

Proc. SPIE. 5453, Micro-Optics, VCSELs, and Photonic Interconnects

KEYWORDS: Optical components, Sensors, Polymers, Glasses, Spectroscopy, Ultraviolet radiation, Structured optical fibers, Connectors, X-ray lithography, Optics manufacturing

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Proceedings Article | 1 September 2004 Paper

Novel design and prototyping of a micro-optical distance sensor considering a distributed fabrication

Uwe Hollenbach, Juergen Mohr, Toru Oka, Ulrike Wallrabe, Ingo Sieber

Proc. SPIE. 5459, Optical Sensing

KEYWORDS: Mirrors, Lenses, Sensors, Manufacturing, Ray tracing, Photomasks, Electro optics, Semiconducting wafers, Optics manufacturing, Prototyping

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Showing 5 of 8 publications

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