Dr. Pentti Karioja Profile

Dr. Pentti Karioja

Principal Scientist at VTT Technical Research Ctr. of Finland Ltd.

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Author

Publications (60)

Proceedings Article | 14 May 2018 Presentation + Paper

Integrated multi-wavelength mid-IR light source for gas sensing

Pentti Karioja, Teemu Alajoki, Matteo Cherchi, Jyrki Ollila, Mikko Harjanne, Noora Heinilehto, Soile Suomalainen, Nouman Zia, Heidi Tuorila, Jukka Viheriälä, Mircea Guina, Ryszard Buczyński, Rafał Kasztelanic, Tomi Salo, Sami Virtanen, Paweł Kluczyński, Lars Borgen, Marcin Ratajczyk, Przemyslaw Kalinowski

Proc. SPIE. 10657, Next-Generation Spectroscopic Technologies XI

KEYWORDS: Mid-IR, Optical filters, Light sources, Gas sensors, Modulation, Sensors, Glasses, Silicon, Photonic integrated circuits, Absorption

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Proceedings Article | 20 February 2017 Presentation + Paper

Multi-wavelength mid-IR light source for gas sensing

Pentti Karioja, Teemu Alajoki, Matteo Cherchi, Jyrki Ollila, Mikko Harjanne, Noora Heinilehto, Soile Suomalainen, Jukka Viheriälä, Nouman Zia, Mircea Guina, Ryszard Buczyński, Rafał Kasztelanic, Ireneusz Kujawa, Tomi Salo, Sami Virtanen, Paweł Kluczyński, Håkon Sagberg, Marcin Ratajczyk, Przemyslaw Kalinowski

Proc. SPIE. 10110, Photonic Instrumentation Engineering IV

KEYWORDS: Packaging, Mid-IR, Photonic devices, Optical filters, Light sources, Gas sensors, Waveguides, Sensors, Glasses, Silicon, Integrated optics, Photonic integrated circuits, Infrared technology, Absorption

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Proceedings Article | 21 May 2014 Paper

Advances in miniature spectrometer and sensor development

Jouko Malinen, Anna Rissanen, Heikki Saari, Pentti Karioja, Mikko Karppinen, Timo Aalto, Kari Tukkiniemi

Proc. SPIE. 9101, Next-Generation Spectroscopic Technologies VII

KEYWORDS: Mid-IR, Electronics, Light emitting diodes, Waveguides, Sensors, Spectroscopy, Ultraviolet radiation, Head, Photonics, Microopto electromechanical systems

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Proceedings Article | 15 May 2014 Paper

Toward large-area roll-to-roll printed nanophotonic sensors

Pentti Karioja, Jussi Hiltunen, Sanna Aikio, Teemu Alajoki, Jarkko Tuominen, Marianne Hiltunen, Samuli Siitonen, Ville Kontturi, Karl Böhlen, Rene Hauser, Martin Charlton, Arjen Boersma, Peter Lieberzeit, Thorsten Felder, David Eustace, Eliav Haskal

Proc. SPIE. 9141, Optical Sensing and Detection III

KEYWORDS: Waveguides, Interferometers, Sensors, Polymers, Ultraviolet radiation, Manufacturing, Photonic crystals, Nanoimprint lithography, Nanophotonics, Semiconducting wafers

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Polymers have become an important material group in fabricating discrete photonic components and integrated optical devices. This is due to their good properties: high optical transmittance, versatile processability at relative low temperatures and potential for low-cost production. Recently, nanoimprinting or nanoimprint lithography (NIL) has obtained a plenty of research interest. In NIL, a mould is pressed against a substrate coated with a moldable material. After deformation of the material, the mold is separated and a replica of the mold is formed. Compared with conventional lithographic methods, imprinting is simple to carry out, requires less-complicated equipment and can provide high-resolution with high throughput. Nanoimprint lithography has shown potential to become a method for low-cost and high-throughput fabrication of nanostructures. We show the development process of nano-structured, large-area multi-parameter sensors using Photonic Crystal (PC) and Surface Enhanced Raman Scattering (SERS) methodologies for environmental and pharmaceutical applications. We address these challenges by developing roll-to-roll (R2R) UV-nanoimprint fabrication methods. Our development steps are the following: Firstly, the proof of concept structures are fabricated by the use of wafer-level processes in Si-based materials. Secondly, the master molds of successful designs are fabricated, and they are used to transfer the nanophotonic structures into polymer materials using sheet-level UV-nanoimprinting. Thirdly, the sheet-level nanoimprinting processes are transferred to roll-to-roll fabrication. In order to enhance roll-to-roll manufacturing capabilities, silicone-based polymer material development was carried out. In the different development phases, Photonic Crystal and SERS sensor structures with increasing complexities were fabricated using polymer materials in order to enhance sheet-level and roll-to-roll manufacturing processes. In addition, chemical and molecular imprint (MIP) functionalization methods were applied in the sensor demonstrators. In this paper, the process flow in fabricating large-area nanophotonic structures by the use of sheet-level and roll-to-roll UV- nanoimprinting is reported.

Proceedings Article | 15 May 2014 Paper

Detection of low concentration formaldehyde gas by photonic crystal sensor fabricated by nanoimprint process in polymer material

A. Boersma, Renz van Ee, Ralph S. Stevens, Milan Saalmink, Martin D. Charlton, Michael Pollard, Ruiqi Chen, Ville Kontturi, Pentti Karioja, Teemu Alajoki

Proc. SPIE. 9141, Optical Sensing and Detection III

KEYWORDS: Refractive index, Sensors, Nanoparticles, Polymers, Silicon, Photonic crystals, Receptors, Nanoimprint lithography, Photorefractive polymers, Polymeric sensors

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Proceedings Article | 1 May 2014 Paper

Polymer and composite polymer slot waveguides

Marianne Hiltunen, William Fegadolli, Hugo L. Lira, Pasi Vahimaa, Jussi Hiltunen, Sanna Aikio, Vilson Almeida, Pentti Karioja

Proc. SPIE. 9133, Silicon Photonics and Photonic Integrated Circuits IV

KEYWORDS: Refractive index, Glucose, Resonators, Waveguides, Polarization, Interferometers, Sensors, Polymers, Silicon, Polymer multimode waveguides

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Proceedings Article | 17 May 2012 Paper

Long single-mode waveguides made by imprint patterning for optical interconnects and sensors

Mikko Karppinen, Jussi Hiltunen, Anna Kokkonen, Jarno Petäjä, Noriyuki Masuda, Marianne Hiltunen, Jarkko Tuominen, Pentti Karioja

Proc. SPIE. 8428, Micro-Optics 2012

KEYWORDS: Optical lithography, Waveguides, Cladding, Sensors, Signal attenuation, Polymers, Manufacturing, Optical interconnects, Optics manufacturing, Polymer multimode waveguides

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Proceedings Article | 8 May 2012 Paper

Layered polymer: inorganic composite waveguides for biosensor applications

Jussi Hiltunen, Meng Wang, Christina Liedert, Sanna Aikio, Noriyuki Masuda, Stuart Pearce, Martin Charlton, Pentti Karioja

Proc. SPIE. 8427, Biophotonics: Photonic Solutions for Better Health Care III

KEYWORDS: Refractive index, Waveguides, Interferometers, Cladding, Sensors, Polymers, Composites, Coating, Biosensors, Polymer multimode waveguides

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Proceedings Article | 31 March 2012

Printed hybrid systems

Pentti Karioja, Jukka-Tapani Mäkinen, Kimmo Keränen, Janne Aikio, Teemu Alajoki, Tuomo Jaakola, Matti Koponen, Antti Keränen, Mikko Heikkinen, Markus Tuomikoski, Riikka Suhonen, Leena Hakalahti, Pälvi Kopola, Jukka Hast, Ralf Liedert, Jussi Hiltunen, Noriyuki Masuda, Antti Kemppainen, Kari Rönkä, Raimo Korhonen

Proc. SPIE. 8344, Nanosensors, Biosensors, and Info-Tech Sensors and Systems 2012

KEYWORDS: Electronics, Light emitting diodes, Sensors, Organic light emitting diodes, Polymers, Solar cells, Manufacturing, Printing, Neodymium, Assembly equipment

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Proceedings Article | 1 June 2011 Paper

UV-imprinting of single-mode polymeric waveguides

Jussi Hiltunen, Meng Wang, Marianne Hiltunen, Jarkko Puustinen, Jyrki Lappalainen, Stuart Pearce, Martin Charlton, Pentti Karioja

Proc. SPIE. 8069, Integrated Photonics: Materials, Devices, and Applications

KEYWORDS: Refractive index, Optical lithography, Waveguides, Cladding, Sensors, Polymers, Composites, Coating, Geometrical optics, Polymer multimode waveguides

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Proceedings Article | 3 May 2011 Paper

Polymer based single and multislot waveguides

M. Hiltunen, J. Hiltunen, Antti Suutala, Jarkko Tuominen, Pentti Karioja

Proc. SPIE. 8068, Bioelectronics, Biomedical, and Bioinspired Systems V; and Nanotechnology V

KEYWORDS: Refractive index, Titanium dioxide, Waveguides, Cladding, Etching, Polymers, Coating, Finite element methods, Photorefractive polymers, Polymer multimode waveguides

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Proceedings Article | 25 November 2010 Paper

Fabrication of polymer waveguide devices for sensor applications

Mu Cheng, Jussi Hiltunen, Meng Wang, Antti Suutala, Pentti Karioja, Risto Myllylä

Proc. SPIE. 7376, Laser Applications in Life Sciences

KEYWORDS: Lithography, Refractive index, Light sources, Waveguides, Sensors, Polymers, Nanoimprint lithography, Polymer thin films, Polymer multimode waveguides, Absorption

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Proceedings Article | 14 May 2010 Paper

LTCC-based differential photo acoustic cell for ppm gas sensing

P. Karioja, K. Keränen, K. Kautio, J. Ollila, M. Heikkinen, I. Kauppinen, T. Kuusela, B. Matveev, M. McNie, R. Jenkins, J. Palve

Proc. SPIE. 7726, Optical Sensing and Detection

KEYWORDS: Gas sensors, Waveguides, Interferometers, Sensors, Glasses, Silicon, Reflectivity, Sapphire, Photoacoustic spectroscopy, Absorption

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Silicon MEMS cantilever-based photoacoustic technology allows for the sensing of ultra low gas concentrations with very wide dynamic range. The sensitivity enhancement is achieved with a cantilever microphone system in which the cantilever displacement is probed with an optical interferometer providing a pico-meter resolution. In the gas sensor, the silicon cantilever microphone is placed in a two-chamber differential gas cell. By monitoring differential pressure changes between the two chambers, the differential cell operates as a differential infra-red detector for optical absorption signals through a measurement and reference path. The differential pressure signal is proportional to gas concentration in the optical measurement path. We have designed, implemented and tested a differential photo acoustic gas cell based on Low Temperature Co-fired Ceramic (LTCC) multilayer substrate technology. Standard LTCC technology enables implementation of 2.5D structures including holes, cavities and channels into the electronic substrate. The implemented differential photoacoustic gas cell structure includes two 10 mm long cylindrical cells, diameter of 2.4 mm. Reflectance measurements of the cell showed that reflectivity of the substrate material can be improved by a factor 15 - 90 in the 3 - 8 μm spectral region using gold or silver paste coatings. A transparent window is required in the differential gas cell structure in order to probe the displacement of the silicon cantilever. The transparent sapphire window was sealed to the LTCC substrate using two methods: screen printed Au80/Sn20 solder paste and pre-attached glass solder paste (Diemat DM2700P/H848). Both methods were shown to provide hermetic sealing of sapphire windows to LTCC substrate. The measured He-leak rate for the 10 sealed test samples implemented using glass paste were less than 2.0 ×10^-9 atm×cm³/s, which meets the requirement for the leak rate according to MIL-STD 883. The achieved hermetic level suggests that the proof-of-principle packaging demonstrator paves the way for implementing a novel differential photoacoustic gas cell for a future miniature gas sensor module. The future module consisting of a sample gas cell and immersion lens IR-LEDs together with interferometric probing of the cantilever microphone is expected to be capable of measuring ultra low concentrations of a wide range of gases with their fundamental absorption bands at 3 - 7 μm wavelength, such as CO, CO2 and CH₄.

Proceedings Article | 24 February 2010 Paper

Differential photo-acoustic gas cell based on LTCC for ppm gas sensing

K. Keränen, K. Kautio, J. Ollila, M. Heikkinen, I. Kauppinen, T. Kuusela, B. Matveev, M. McNie, R. Jenkins, P. Karioja

Proc. SPIE. 7607, Optoelectronic Interconnects and Component Integration IX

KEYWORDS: Gas sensors, Light emitting diodes, Waveguides, Interferometers, Sensors, Silicon, Reflectivity, Sapphire, Photoacoustic spectroscopy, Absorption

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Silicon MEMS cantilever-based photoacoustic technology allows for the sensing of ultra low gas concentrations with very wide dynamic range. The sensitivity enhancement is achieved with a cantilever microphone system in which the cantilever displacement is probed with an optical interferometer providing a pico-meter resolution. In the gas sensor, the silicon cantilever microphone is placed in a two-chamber differential gas cell. By monitoring differential pressure changes between the two chambers, the differential cell operates as a differential infra-red detector for optical absorption signals through a measurement and reference path. The differential pressure signal is proportional to gas concentration in the optical measurement path. We have designed, implemented and tested a differential photo-acoustic gas cell based on Low Temperature Co-fired Ceramic (LTCC) multilayer substrate technology. Standard LTCC technology enables implementation of 2.5D structures including holes, cavities and channels into the electronic substrate. The implemented differential photoacoustic gas cell structure includes two 10 mm long cylindrical cells, diameter of 2.4 mm. Reflectance measurements of the cell showed that reflectivity of the substrate material can be improved by a factor 15 - 90 in the 3 - 8 μm spectral region using gold or silver paste coatings. A transparent window is required in the differential gas cell structure in order to probe the displacement of the silicon cantilever. The transparent sapphire window was sealed to the LTCC substrate using two methods: screen printed Au80/Sn20 solder paste and pre-attached glass solder paste (Diemat DM2700P/H848). Both methods were shown to provide hermetic sealing of sapphire windows to LTCC substrate. The measured He-leak rate for the 10 sealed test samples implemented using glass paste were under 2.0 ×10^-9 atm×cm3/s, which meets the requirement for the leak rate according to MIL-STD 883. The achieved hermeticity level suggests that the proof-of-principle packaging demonstrator paves the way for implementing a novel differential photoacoustic gas cell for a future miniature gas sensor module. The future module consisting of a sample gas cell and immersion lens IR LEDs together with interferometric probing of the cantilever microphone is expected to be capable of measuring ultra low concentrations of a wide range of gases with their fundamental absorption bands at 3 - 7 μm wavelength, such as CO, CO₂ and CH₄.

Proceedings Article | 15 May 2008 Paper

Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects

C. Debaes, J. Van Erps, M. Karppinen, J. Hiltunen, H. Suyal, A. Last, M. Lee, P. Karioja, M. Taghizadeh, J. Mohr, H. Thienpont, A. Glebov

Proc. SPIE. 6992, Micro-Optics 2008

KEYWORDS: Lithography, Waveguides, Sensors, Polymers, Ultraviolet radiation, Scanning electron microscopy, Optoelectronics, Photomasks, Optical interconnects, Multiphoton lithography

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Proceedings Article | 1 May 2008 Paper

Electro-optical properties of BaTiO3-SrTiO3 multilayer thin films for waveguide modulators

Jussi Hiltunen, Mikko Karppinen, Pentti Karioja, Jyrki Lappalainen, Jarkko Puustinen, Vilho Lantto, Harry Tuller

Proc. SPIE. 6996, Silicon Photonics and Photonic Integrated Circuits

KEYWORDS: Thin films, Multilayers, Waveguides, Polarization, Satellites, Electrodes, Modulators, Electro optics, Superlattices, Thin film devices

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Proceedings Article | 16 May 2007 Paper

Inmould integration of a microscope add-on system to a 1.3 Mpix camera phone

Jukka-Tapani Mäkinen, Kimmo Keränen, Jehki Hakkarainen, Mikko Silvennoinen, Timo Salmi, Seppo Syrjälä, Anneli Ojapalo, Marcus Schorpp, Pekka Hoskio, Pentti Karioja

Proc. SPIE. 6585, Optical Sensing Technology and Applications

KEYWORDS: Microscopes, Optical design, Light emitting diodes, Imaging systems, Cameras, Image resolution, Lens design, Integrated optics, Optics manufacturing, Prototyping

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Proceedings Article | 16 May 2007 Paper

Low temperature co-fired ceramics on optoelectronic sensors integration

Ville Moilanen, Kari Kautio, Pentti Karioja, Raimo Rikola, Jarmo Lehtomaa, Jouko Malinen

Proc. SPIE. 6585, Optical Sensing Technology and Applications

KEYWORDS: Packaging, Light emitting diodes, Sensors, Ceramics, Detector arrays, Infrared radiation, Chemical elements, Signal detection, Assembly equipment, Lead

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Proceedings Article | 1 May 2007 Paper

Injection moulding integration of a red VCSEL illuminator module for a hologram reader sensor

Kimmo Keränen, Toni Saastamoinen, Jukka-Tapani Mäkinen, Mikko Silvennoinen, Ilpo Mustonen, Pasi Vahimaa, Timo Jääskeläinen, Ari Lehto, Anneli Ojapalo, Marcus Schorpp, Pekka Hoskio, Pentti Karioja

Proc. SPIE. 6585, Optical Sensing Technology and Applications

KEYWORDS: Packaging, Modeling, Diamond, Manufacturing, Optical alignment, Vertical cavity surface emitting lasers, Optics manufacturing, Assembly tolerances, Prototyping, Fiber optic illuminators

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A red VCSEL illuminator module demonstrator was manufactured by injection moulding integration. A red VCSEL chip was first attached to a simple FR4 substrate, which contains bonding pads and conducting wires for the VCSEL chip attachment and electrical driving. The substrate was then placed as an insert in an injection mould. The VCSEL chip shielding and optics formation was made in a one-step injection moulding process. The used optical thermoplastic in the processing was polycarbonate (PC). The pursued optical function of the single spherical surface attained in the moulding was to collimate the emitted red light (&lgr;=664.5 nm) from the VCSEL chip. The main critical issue related to the manufacturing of the illuminator module in the injection moulding process was the durability of bonding wire contacts. A single 25 &mgr;m diameter gold wire was used in wire bonding in order to create the upper contact to the chip. The lower contact was processed by attaching the chip to the substrate using conductive epoxy. A test series of 20 modules using FR4 substrate materials were produced. The number of fully operative modules was 12 resulting total module yield of 60%. The main reason for a non-operative module was loosening of the bonding wire during the injection moulding process. The bonding wire durability in the moulding process can be improved by using glob-top shielding of the VCSEL device before injection moulding and using a lower holding pressure in the injection moulding process. A diamond turned insert was used in the mould in order to create a high quality lens surface on the top of the VCSEL chip. The tower average length after one iteration round by mould modification was 8.676 &mgr;m, so the measured value was on average 20 &mgr;m larger than nominal value. The measured RMS roughness of the processed lens surface was 5 ... 7 nm and the radius -3.23 ... 3.83 mm. The radius of the lens and the length of the tower varied depending of the used process parameters. The manufactured illumination module can be integrated with a CMOS image matrix sensor in order to form a compact hologram reader system. The injection moulding integration principle seems to be very promising method to manufacture intelligently integrated and cost-effective optoelectronic products according to experience with this demonstrator.

Proceedings Article | 21 April 2006 Paper

Parallel optical interconnect between surface-mounted devices on FR4 printed wiring board using embedded waveguides and passive optical alignments

Mikko Karppinen, Teemu Alajoki, Antti Tanskanen, Kari Kataja, Jukka-Tapani Mäkinen, Pentti Karioja, Marika Immonen, Jorma Kivilahti

Proc. SPIE. 6185, Micro-Optics, VCSELs, and Photonic Interconnects II: Fabrication, Packaging, and Integration

KEYWORDS: Transmitters, Microlens array, Waveguides, Receivers, Monte Carlo methods, Micromirrors, Optical alignment, Vertical cavity surface emitting lasers, Optical interconnects, Tolerancing

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Proceedings Article | 21 April 2006 Paper

Cost-efficient hermetic fibre pigtailed laser module utilizing passive device alignment on an LTCC substrate

K. Keränen, J. Ollila, J.-T Mäkinen, K. Kautio, P. Korhonen, V. Heikkinen, O. Väätäinen, J. Heilala, P. Karioja

Proc. SPIE. 6185, Micro-Optics, VCSELs, and Photonic Interconnects II: Fabrication, Packaging, and Integration

KEYWORDS: Packaging, Modeling, Glasses, Manufacturing, Fiber lasers, Semiconductor lasers, Monte Carlo methods, Optical simulations, Tolerancing, Prototyping

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A hermetic fibre pigtailed laser module utilizing passive device alignment on a low temperature co-fired ceramics (LTCC) substrate is demonstrated. The 3-dimensional shape of the laminated and fired ceramic substrate provides the necessary alignment structures including holes, grooves and cavities for the laser to fibre coupling. The achieved passive alignment accuracy allows high coupling efficiency realizations of multi-mode fibre pigtailed laser modules. The ceramic substrate is intrinsically hermetic and it opens up a possibility to produce cost efficient hermetic packaging. In our concept hermetic sealing is produced by utilizing Kovar frame, which is soldered to an LTCC substrate. Kovar frame has a hole for fibre feed-trough and a hermetic glass-metal sealing between fibre and frame is processed using glass preform. The heart of the module is a power laser diode chip, which can produce several watts of continuous power. The module, however, can be finally used as a transmitter in a laser pulse time-of-flight distance sensor and in this application it can be overdriven by a factor of 10. This means that the peak optical power in the pulses can be several tens of watts. The laser chip allows this kind of overdriving due to the fact that the duty factor in the operation is only 0.0001 at 2 kHz pulsing frequency. Optical coupling efficiency of the multi-mode laser system was simulated using optical systems simulation software. The nominal coupling efficiency between 210 μm x 1μm stripe laser and 200/220 μm step index fibre (NA=0.22) was 0.65. The simulated coupling efficiency was verified by prototype realization and characterization. The measured average coupling efficiency of the hermetically sealed prototypes was 0.39. The coupling efficiencies of prototypes varied from 0.14 to 0.64. Leak rate of 1 x 10^-7 [atm x cm³/s] was measured in the helium leak tests for the final prototype module, when the module was tested according to MIL-STD-883D method 1014.9 specification. Leak rate for the module using a buffer stripper fibre without a rubber guard tube was 3 x 10^-9 [atm x cm³/s]. The background helium level before and after the tests was less than 3 x 10^-10[atm x cm³/s]. This clearly higher leak rate in the final module leak measurement is mainly due to the absorbed helium to the fibre polymer buffer layer and rubber guard tube in the pressurization process. Measurements show that the implemented module is hermetic. Cost-of-ownership modelling was performed starting from low production volume up to production of 10 million good modules per year. Module production cost was estimated through COO modelling. Modelling forecasted that the module production can be lower than 10 EUR in high volume production.

Proceedings Article | 21 April 2006 Paper

Packaging a free-space intra-chip optical interconnect module: Monte Carlo tolerance study and assembly results

Michael Vervaeke, Markku Lahti, Mikko Karpinnen, Christof Debaes, Bart Volckaerts, Pentti Karioja, Hugo Thienpont

Proc. SPIE. 6185, Micro-Optics, VCSELs, and Photonic Interconnects II: Fabrication, Packaging, and Integration

KEYWORDS: Packaging, Optical spheres, Error analysis, 3D modeling, Monte Carlo methods, Optical simulations, Optical interconnects, Adhesives, Tolerancing, Assembly tolerances

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In this paper we give an overview of the fabrication and assembly induced performance degradation of an intra-multi-chip-module free-space optical interconnect, integrating micro-lenses and a deflection prism above a dense opto-electronic chip. The proposed component is used to demonstrate the capabilities of an accurate micro-optical rapid prototype technique, namely the Deep Proton Writing (DPW). To evaluate the accuracy of DPW and to assess whether our assembly scheme will provide us with a reasonable process yield, we have built a simulation framework combining mechanical Monte Carlo analysis with optical simulations. Both the technological requirements to ensure a high process yield, and the specifications of our in-house DPW technology are discussed. Therefore, we first conduct a sensitivity analysis and we subsequently simulate the effect of combined errors using a Monte Carlo simulation. We are able to investigate the effect of a technology accuracy enhancement on the fabrication and assembly yield by scaling the standard deviation of the errors proportionally to each sensitivity interval. We estimate that 40% of the systems fabricated with DPW will show an optical transmission efficiency above -4.32 dB, which is -3 dB below the theoretical obtainable value. We also discuss our efforts to implement an opto-mechanical Monte Carlo simulator. It enables us to address specific issues not directly related with the micro-optical or DPW components, such as the influence of glueing layers and structures that allow for self-alignment, by combining mechanical tolerancing algorithms with optical simulation software. More in particular we determined that DPW provides ample accuracy to meet the requirements to obtain a high manufacturing yield. Finally, we shortly highlight the basic layout of a completed demonstrator. The adhesive bonding of opto-electronic devices in their package is subject to further improvement to enhance the tilt accuracy of the devices with respect to the optical interconnect modules.

Proceedings Article | 20 October 2005 Paper

Implementing a prototyping network for injection moulded imaging lenses in Finland

K. Keränen, J.-T. Mäkinen, E.J. Pääkkönen, M. Koponen, M. Karttunen, J. Hiltunen, P. Karioja

Proc. SPIE. 5965, Optical Fabrication, Testing, and Metrology II

KEYWORDS: Lenses, Cameras, Manufacturing, Surface roughness, Lens design, Modulation transfer functions, Tolerancing, Optics manufacturing, Prototyping, Surface finishing

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A network for prototyping imaging lenses using injection moulding was established in Finland. The network consists of several academic and industrial partners capable of designing, processing and characterising imaging lenses produced by injection moulding technology. In order to validate the operation of the network a demonstrator lens was produced. The process steps included in the manufacturing were lens specification, designing and modelling, material selection, mould tooling, moulding process simulation, injection moulding and characterisation. A magnifying imaging singlet lens to be used as an add-on in a camera phone was selected as a demonstrator. The design of the add-on lens proved to be somewhat challenging, but a double aspheric singlet lens design fulfilling nearly the requirement specification was produced. In the material selection task the overall characteristics profile of polymethyl methacrylate (PMMA) material was seen to be the most fitting to the pilot case. It is a low cost material with good moulding properties and therefore it was selected as a material for the pilot lens. Lens mould design was performed using I-DEAS and tested by using MoldFlow 3D injection moulding simulation software. The simulations predicted the achievable lens quality in the processing, when using a two-cavity mould design. First cavity was tooled directly into the mould plate and the second cavity was made by tooling separate insert pieces for the mould. Mould material was steel and the inserts were made from Moldmax copper alloy. Parts were tooled with high speed milling machines. Insert pieces were hand polished after tooling. Prototype lenses were injection moulded using two PMMA grades, namely 6N and 7N. Different process parameters were also experimented in the injection moulding test runs. Prototypes were characterised by measuring mechanical dimensions, surface profile, roughness and MTF of the lenses. Characterisations showed that the lens surface RMS roughness was 30-50 nm and the profile deviation was 5 μm from the design at a distance of 0.3 mm from the lens vertex. These manufacturing defects caused that the measured MTF values were lower than designed. The lens overall quality, however, was adequate to demonstrate the concept successfully. Through the implementation of the demonstrator lens we could test effectively different stages of the manufacturing process and get information about process component weight and risk factors and validate the overall performance of the network.

Proceedings Article | 8 September 2004 Paper

Comprehensive modeling of interferometric hydrophone with self-supported mandrel transducer

Pawel Wierzba, Pentti Karioja

Proc. SPIE. 5576, Lightguides and their Applications II

KEYWORDS: Optical fibers, Modeling, Silicon, Interferometry, 3D modeling, Transducers, Finite element methods, Aluminum, Epoxies, Acoustics

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Proceedings Article | 8 September 2004 Paper

Modeling of active fiber Bragg grating underwater acoustic sensor

Pawel Wierzba, Pentti Karioja

Proc. SPIE. 5576, Lightguides and their Applications II

KEYWORDS: Modeling, Fiber Bragg gratings, Sensors, Coating, Fiber lasers, Transducers, Finite element methods, Acoustics, Signal detection, Active sensors

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Proceedings Article | 8 September 2004 Paper

Embedded optical interconnect on printed wiring board

Mikko Karppinen, Jukka-Tapani Makinen, Kari Kataja, Antti Tanskanen, Teemu Alajoki, Pentti Karioja, Marika Immonen, Jorma Kivilahti

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

KEYWORDS: Transmitters, Microlens array, Waveguides, Lenses, Polymers, Receivers, Monte Carlo methods, Optical alignment, Vertical cavity surface emitting lasers, Tolerancing

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Proceedings Article | 18 August 2004 Paper

Photo-crosslinkable hybrid material with improved aging stability for integrated optics

Maja Kusevic, Arto Maaninen, Jussi Hiltunen, Marianne Hiltunen, Jarkko Tuominen, Pentti Karioja

Proc. SPIE. 5451, Integrated Optics and Photonic Integrated Circuits

KEYWORDS: Optical components, Refractive index, Waveguides, Interferometers, Signal attenuation, Silicon, Materials processing, Integrated optics, Sol-gels, Zirconium dioxide

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Proceedings Article | 10 June 2004 Paper

Optical interconnect on printed wiring board

Mikko Karppinen, Jukka-Tapani Makinen, Kari Kataja, Antti Tanskanen, Teemu Alajoki, Pentti Karioja, Marika Immonen, Jorma Kivilahti

Proc. SPIE. 5358, Photonics Packaging and Integration IV

KEYWORDS: Transmitters, Waveguides, Lenses, Sensors, Receivers, Monte Carlo methods, Optical alignment, Vertical cavity surface emitting lasers, Optical interconnects, Tolerancing

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Proceedings Article | 10 June 2004 Paper

Cost-effective packaging of laser modules using LTCC substrates

Kimmo Keranen, Jukka-Tapani Makinen, Juhani Heilala, Otso Vaatainen, Kari Kautio, Jyrki Ollila, Jarno Petaja, Mikko Karppinen, Veli Heikkinen, Pentti Karioja

Proc. SPIE. 5358, Photonics Packaging and Integration IV

KEYWORDS: Packaging, Multimode fibers, Manufacturing, Fiber lasers, Semiconductor lasers, Monte Carlo methods, Optical simulations, Optical alignment, Tolerancing, Optics manufacturing

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Proceedings Article | 18 February 2004 Paper

Imaging lens design using image quality metric

Jean-Luc Olives, Timo Kolehmainen, Janne Aikio, Kari Kataja, Pentti Karioja, Tero Vuori, T. Mustonen

Proc. SPIE. 5249, Optical Design and Engineering

KEYWORDS: Signal to noise ratio, Visualization, Imaging systems, Sensors, Lens design, Image quality, LCDs, Image sensors, Objectives, Modulation transfer functions

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Proceedings Article | 22 January 2004 Paper

Simulation of imaging system's performance

Timo Kolehmainen, Janne Aikio, Mikko Karppinen, Antti-Jussi Mattila, Jukka-Tapani Makinen, Kari Kataja, Kari Tukkiniemi, Pentti Karioja

Proc. SPIE. 5178, Optical Modeling and Performance Predictions

KEYWORDS: Point spread functions, Visualization, Imaging systems, Sensors, Lens design, Image quality, Image sensors, Raster graphics, Modulation transfer functions, RGB color model

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Proceedings Article | 22 January 2004 Paper

Prototyping of miniature plastic imaging lens

Jukka-Tapani Makinen, Janne Aikio, Veli-Pekka Putila, Kimmo Keranen, Pentti Karioja, Timo Kolehmainen, Janne Haavisto

Proc. SPIE. 5178, Optical Modeling and Performance Predictions

KEYWORDS: Optomechanical design, Optical design, Manufacturing, Lens design, Image quality, Tolerancing, Optics manufacturing, Performance modeling, Prototyping, Design for manufacturability

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Proceedings Article | 18 June 2002 Paper

Sol-gel technologies for multimode waveguide devices

Pentti Karioja, Maja Kusevic, Marianne Hiltunen, Janne Paaso, Jukka-Tapani Maekinen, Jussi Hiltunen, Kari Kautio, Harri Kopola

Proc. SPIE. 4640, Integrated Optics: Devices, Materials, and Technologies VI

KEYWORDS: Packaging, Optical lithography, Waveguides, Ceramics, Manufacturing, 3D modeling, Sol-gels, Optical alignment, Tolerancing, Systems modeling

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Proceedings Article | 18 June 2002 Paper

Extremely short external cavity lasers: the use of wavelength tuning effects in near field sensing

Janne Aikio, Kari Kataja, Teemu Alajoki, Pentti Karioja, Dennis Howe

Proc. SPIE. 4640, Integrated Optics: Devices, Materials, and Technologies VI

KEYWORDS: Mirrors, Tunable lasers, Sensors, Reflectivity, Semiconductor lasers, Near field, Laser resonators, Wavelength tuning, Laser optics, Optical discs

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SPIE Journal Paper | 1 April 2002

Wireless infrared data links: ray-trace simulations of diffuse channelsand demonstration of diffractive element for multi-beam transmitters

Mikko Karppinen, Kari Kataja, Jukka-Tapani Maekinen, Sanna Aikio, Hannu Rajaniemi, Pertti Paeaekkoenen, Jari Turunen, Juha Rantala, Pentti Karioja

OE Vol. 41 Issue 04

KEYWORDS: Transmitters, Sensors, Monte Carlo methods, Scattering, Receivers, Vertical cavity surface emitting lasers, Computer simulations, Diffraction, Ray tracing, Data modeling

Proceedings Article | 10 January 2002 Paper

Technical considerations for optical disks in cellular mobile terminals

Jakke Makela, Mikko Juhola, Janne Aikio, Pentti Karioja

Proc. SPIE. 4342, Optical Data Storage 2001

KEYWORDS: Cell phones, Roentgenium, Optical storage, Optical discs, Standards development, Francium

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SPIE Journal Paper | 1 January 2002

Comparison of distributed fiber optic sensing methods for location and quantity information measurements

Ilkka Alasaarela, Pentti Karioja, Harri Kopola

OE Vol. 41 Issue 01

KEYWORDS: Sensors, Spatial resolution, Modulation, Polarization, Fiber optics sensors, Time metrology, Interferometry, Light scattering, Scattering, Kerr effect

Proceedings Article | 13 December 2001 Paper

Passively aligned fiber-optic transmitter integrated into LTCC module

Mikko Karppinen, Kari Kautio, Mikko Haekkinen, Jonna Haekkilae, Pentti Karioja, Tomi Jouhti, Ari Tervonen, Markku Oksanen

Proc. SPIE. 4455, Micro- and Nano-optics for Optical Interconnection and Information Processing

KEYWORDS: Multimode fibers, Transmitters, Electronics, Fiber optics, Manufacturing, Structured optical fibers, Optical alignment, Vertical cavity surface emitting lasers, Tolerancing, Prototyping

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Proceedings Article | 13 December 2001 Paper

Free-space optical backplanes based on beaconlike links or on a ring bus

Mikko Karppinen, Jukka-Tapani Maekinen, Antti Kemppainen, Marianne Borenius, Pentti Karioja

Proc. SPIE. 4455, Micro- and Nano-optics for Optical Interconnection and Information Processing

KEYWORDS: Transmitters, Mirrors, Sensors, Signal attenuation, Receivers, Free space optics, Optical alignment, Vertical cavity surface emitting lasers, Optical interconnects, Tolerancing

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Proceedings Article | 8 November 2001 Paper

Optical information storage in cellular mobile terminals

Jakke Makela, Janne Aikio, Venkatesh Vadde, Timo Kolehmainen, Pentti Karioja

Proc. SPIE. 4534, Optoelectronic and Wireless Data Management, Processing, Storage, and Retrieval

KEYWORDS: Data storage, Interfaces, Manufacturing, Magnetism, Compact discs, Optical storage, Solid state electronics, Optics manufacturing, Optical discs, Standards development

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SPIE Journal Paper | 1 October 2001

Miniaturization and module integration of an infrared spectrometer

Kimmo Keraenen, Pentti Karioja, Martti Blomberg, Jussi Tenhunen, Outi Rusanen, Harri Kopola

OE Vol. 40 Issue 10

KEYWORDS: Silicon, Sensors, Systems modeling, Infrared spectroscopy, Signal detection, Spectroscopy, Infrared radiation, System integration, Adhesives, Geometrical optics

Proceedings Article | 1 September 2000 Paper

Fabrication and packaging of optical components and microsystems

Juha Rantala, Janne Aikio, Pentti Karioja, Michael Descour, Harri Kopola, Jorma Lammasniemi

Proc. SPIE. 4075, Micro-Opto-Electro-Mechanical Systems

KEYWORDS: Packaging, Optical components, Mirrors, Tunable lasers, Glasses, Silicon, Reflectivity, Fiber lasers, Semiconductor lasers, Optical alignment

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Proceedings Article | 27 April 2000 Paper

Ray-tracing simulations of free-space optical channels for impulse response studies of indoor data links

Mikko Karppinen, Sanna Aikio, Jukka-Tapani Maekinen, Hannu Rajaniemi, Pentti Karioja

Proc. SPIE. 3952, Optoelectronic Interconnects VII; Photonics Packaging and Integration II

KEYWORDS: Transmitters, Scattering, Sensors, Receivers, Computer simulations, Monte Carlo methods, Ray tracing, Infrared radiation, Optical simulations, Free space optics

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SPIE Journal Paper | 1 April 2000

All-optical fiber optic interface for sensors and actuators

Pentti Karioja, Risto Jurva, Kimmo Keraenen, Kari Tukkiniemi, Jouko Haapamaa, Ari Tervonen, Marja Englund

OE Vol. 39 Issue 04

KEYWORDS: Waveguides, Sensors, Integrated optics, Photovoltaics, Solar cells, Actuators, Interfaces, Fiber optics sensors, Light emitting diodes, Data transmission

Proceedings Article | 10 March 2000 Paper

Diffractive optical element in free-space data transmission systems

Kari Kataja, Pertti Paakkonen, Jari Turunen, Juha Rantala, Pentti Karioja

Proc. SPIE. 3951, Diffractive/Holographic Technologies and Spatial Light Modulators VII

KEYWORDS: Transmitters, Diffraction, Diffractive optical elements, Sensors, Data transmission, CCD cameras, Beam shaping, Vertical cavity surface emitting lasers, Chemical elements, Binary data

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Proceedings Article | 6 August 1999 Paper

Wavelength-tunable hybrid laser diode realized by using an electrostatically tuned silicon micromachined Fabry-Perot interferometer

Janne Aikio, Yakov Sidorin, Martti Blomberg, Pentti Karioja

Proc. SPIE. 3625, Physics and Simulation of Optoelectronic Devices VII

KEYWORDS: Reflectors, Mirrors, Fabry–Perot interferometers, Tunable lasers, Gaussian beams, Fabry–Perot interferometry, Reflection, Reflectivity, Semiconductor lasers, Instrument modeling

Proceedings Article | 30 April 1999 Paper

Main characteristics of a miniaturized multipurpose infrared spectrometer

Kimmo Keraenen, Martti Blomberg, Outi Rusanen, Pentti Karioja, Jussi Tenhunen, Harri Kopola, Ari Lehto

Proc. SPIE. 3631, Optoelectronic Integrated Circuits and Packaging III

KEYWORDS: Thermography, Mirrors, Modulation, Sensors, Spectroscopy, Silicon, Infrared spectroscopy, Infrared radiation, Signal detection, Adhesives

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Proceedings Article | 30 April 1999 Paper

Noise measurement of micromachined bolometers

Pawel Wierzba, Pentti Karioja, Harri Kopola

Proc. SPIE. 3730, Optoelectronic and Electronic Sensors III

KEYWORDS: Bolometers, Electronics, Switches, Sensors, Resistance, Amplifiers, Optoelectronics, Micromachining, Resistors, Bandpass filters

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Proceedings Article | 4 December 1998 Paper

Accurate manufacturing and production of optoelectronic parts and modules

Tapio Hannula, Pentti Karioja, Kimmo Keraenen, Harri Kopola, Jouko Malinen, Jyrki Ollila

Proc. SPIE. 3491, 1998 International Conference on Applications of Photonic Technology III: Closing the Gap between Theory, Development, and Applications

KEYWORDS: Packaging, Electronics, Mechanics, Sensors, Metals, Glasses, Spectroscopy, Silicon, Manufacturing, Optoelectronics

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Proceedings Article | 17 June 1998 Paper

Fiber optic sensors for traffic monitoring applications

Pekka Suopajaervi, Riku Pennala, Mikko Heikkinen, Pentti Karioja, Veijo Lyori, Risto Myllylae, Seppo Nissilae, Harri Kopola, Heikki Suni

Proc. SPIE. 3325, Smart Structures and Materials 1998: Smart Systems for Bridges, Structures, and Highways

KEYWORDS: Optical fibers, Roads, Modulation, Speckle, Sensors, Signal attenuation, Structured optical fibers, Fiber optics sensors, Speckle pattern, Signal detection

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Proceedings Article | 15 March 1998 Paper

Hybridization, assembling, and testing of miniaturized optoelectronic modules for sensors and microsystems

Harri Kopola, Pentti Karioja, Outi Rusanen, Heikki Lehto, Jorma Lammasniemi

Proc. SPIE. 3276, Miniaturized Systems with Micro-Optics and Micromechanics III

KEYWORDS: Packaging, Spectrographs, Electronics, Light emitting diodes, Microsystems, Sensors, Spectroscopy, Silicon, Manufacturing, Optoelectronics

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Proceedings Article | 24 September 1997 Paper

Electrically tunable NIR spectrometer

Kimmo Keraenen, Pentti Karioja, Outi Rusanen, Jussi Tenhunen, Martti Blomberg, Heikki Lehto

Proc. SPIE. 3099, Micro-optical Technologies for Measurement, Sensors, and Microsystems II and Optical Fiber Sensor Technologies and Applications

KEYWORDS: Packaging, Near infrared, Optical filters, Mirrors, Fabry–Perot interferometry, Spectrometers, Silicon, Interference filters, Manufacturing, Adhesives

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Proceedings Article | 24 September 1997 Paper

Fiber-optic security monitoring sensor

Marja Englund, Ari Ipatti, Pentti Karioja

Proc. SPIE. 3099, Micro-optical Technologies for Measurement, Sensors, and Microsystems II and Optical Fiber Sensor Technologies and Applications

KEYWORDS: Optical fibers, Fiber optics, Sensors, Structured optical fibers, Fiber optics sensors, Speckle pattern, Electromagnetic interference, Optical fiber cables

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Proceedings Article | 6 June 1997 Paper

Wavelength tuning and intensity noise in diode laser butt coupling

Yakov Sidorin, Pentti Karioja, Dennis Howe

Proc. SPIE. 2994, Physics and Simulation of Optoelectronic Devices V

KEYWORDS: Reflectors, Mirrors, Fabry–Perot interferometers, Modulation, Reflectivity, Fiber lasers, Semiconductor lasers, Wavelength tuning, Diodes, Laser damage threshold

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Proceedings Article | 23 January 1997 Paper

Integrated optics for instrumentation applications

Pentti Karioja, Jouko Lammasniemi, Ari Tervonen, Seppo Honkanen

Proc. SPIE. 2997, Integrated Optics Devices: Potential for Commercialization

KEYWORDS: Actuators, Photovoltaics, Light emitting diodes, Waveguides, Fiber optics, Sensors, Solar cells, Data transmission, Semiconductor lasers, Integrated optics

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SPIE Journal Paper | 1 September 1995

Passive fiber optic bus using bidirectional integrated optic bus access couplers

Pentti Karioja, Simo Tammela, Ari Tervonen, Seppo Honkanen

OE Vol. 34 Issue 09

KEYWORDS: Integrated optics, Fiber optics, Ion exchange, Optics manufacturing, Waveguides, Process modeling

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Proceedings Article | 4 April 1994 Paper

Optical attenuator using liquid crystal film

Pentti Karioja, Arto Karppinen, Harri Kopola, Risto Myllylae

Proc. SPIE. 2175, Liquid Crystal Materials, Devices, and Applications III

KEYWORDS: Packaging, Scattering, Electrodes, Polymers, Glasses, Silicon, Attenuators, Liquid crystals, Adhesives, Optical attenuators

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Proceedings Article | 13 August 1993 Paper

Properties of scattering liquid crystal films

Arto Karppinen, Harri Kopola, Risto Myllylae, Pentti Karioja

Proc. SPIE. 1911, Liquid Crystal Materials, Devices, and Applications II

KEYWORDS: Refractive index, Optical properties, Scattering, Glasses, Particles, Light scattering, Rayleigh scattering, Liquid crystals, Epoxies, Geometrical optics

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Proceedings Article | 24 June 1993 Paper

Inexpensive packaging techniques of fiber pigtailed laser diodes

Pentti Karioja, Kari Tukkiniemi, Veli Heikkinen, Ilkka Kaisto

Proc. SPIE. 1851, Processing and Packaging of Semiconductor Lasers and Optoelectronic Devices

KEYWORDS: Packaging, Silicon, Laser welding, Fiber lasers, Semiconductor lasers, Optical alignment, Adhesives, Tolerancing, Pulsed laser operation, Temperature metrology

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Proceedings Article | 1 December 1991 Paper

Integrated optics bus access module for intramachine communication

Pentti Karioja, Simo Tammela, Tapio Hannula

Proc. SPIE. 1533, Optomechanics and Dimensional Stability

KEYWORDS: Optomechanical design, Electronics, Light emitting diodes, Waveguides, Integrated optics, Optical fiber cables, Connectors, Adhesives, Tolerancing, Ion exchange

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