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conference on current developments in Lens design and optical engineering vII

作者： Jeong, Ho-Seop Yoo, Ho-Sik Lee, Sang-Hyuk Oh, Hae-Ran Samsung Elect Mech Cent R&D Inst Opt Lab Suwon 443743 South Korea

ISBN: (纸本)0819463671

Aspherical glass or plastic lenses are usually adapted in the camera module of handheld phone. Recently, slimmer cameras are required according to reducing thickness of handheld phone. In this paper, we present an ultra slim camera module using multiple freeform off-axis imaging lenses. New optical concept of multiple lens system introduces the planar optics with freeform. shaped aspherical lens surface on the wafer, which can achieve the thickness of 50% compared to the conventional symmetric lens system. In order to achieve the resolution specification, we separate the field of view in camera module. As the result, two inverted images are produced on a same imaging sensor and the acquired inverted images are processed by photo stitching algorithm so as to combine them. Finally, in order to verify the new imaging system, we manufacture the new slim lens through the LJv embossing replication process. We found the new imaging system is feasible for vGA resolution and it can be expandable to the high resolution system.

关键词： freeform. surface planar integrated optics photo stitching wafer scale lens Uv embossing

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Commissioning of the first Precessions 1.2m CNC Polishing Machines for Large Optics

Commissioning of the first <i>Precessions</i> 1.2m CNC Polis...

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conference on current developments in Lens design and optical engineering vII

作者： Walker, D. D. Beaucamp, A. T. H. Doubrovski, v. Dunn, C. Evans, R. Freeman, R. McCavana, G. Morton, R. Riley, D. Simms, J. Yu, G. Wei, X. Univ Coll London Natl Facil Ultra Precis Surfaces OpTIC Technium St Asaph Business Pk St Asaph LL17 0JD Wales Zeeko Ltd Leicester LE67 3FW Leics England

ISBN: (纸本)0819463671

This paper reports on the commissioning of the first of Zeeko's 'IRP1200' 1.2m capacity 7-axis automated CNC polishing machines. These combo machines now support five different removal regimes, which are described. The machines differ substantially from Zeeko's more familiar 200mm machines on which we have focused before, in terms of overall architecture and detailed design. Large and small optics place different demands on part-fixturing, tooling, machine speeds and accelerations, metrology, slurry-handling, part-loading and access etc. These have had a profound effect on the development-path from 200 to 1.2m machines. Moreover, an advance in the kinematic design has extended the allowable range of surface slope-angles from typically 30 degrees up to a hemisphere. The paper presents results from the pass-off trials, the first fluid-jet experiment, and the development of tooling to address a requirement to smooth a part with a local defect.

关键词： Polishing Surface finishing Aspheric lenses Polishing equipment Raster graphics Spherical lenses Optics manufacturing Crystals Oxides Polyurethane

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GHz serial passive clock distribution in vLSI using bidirectional signaling

GHz serial passive clock distribution in VLSI using bidirect...

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IEEE Custom Integrated Circuits conference

作者： Prodanov, v. Banu, M. MHI Consulting LLC NJ United States

ISBN: (纸本)1424400759

We introduce a serial passive clock distribution technique allowing efficient and accurate skew removal at any arbitrary clock drop point. The passive transmission medium may be on-chip electrical transmission lines built in current IC technology or possible optical wave-guides in future developments. The proposed technique is naturally insensitive to practical loses and other non ideal effects and has the capability of covering large chip areas.

关键词： vLSI clocks integrated circuit design optical waveguides signalling transmission lines electrical transmission lines integrated circuits serial passive clock distribution skew removal

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design of miniaturized optoelectronic systems using resonant micro scanning mirrors for projection of full-color images

Design of miniaturized optoelectronic systems using resonant...

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conference on current developments in Lens design and optical engineering vII

作者： Scholles, M. Braeuer, A. Frommhagen, K. Gerwig, Ch. Hoefer, B. Lakner, H. Schenk, H. Schwarzenberg, M. Fraunhofer Inst Photon Microsyst Maria Reiche Str 2 D-01109 Dresden Germany Fraunhofer Inst Appl Opt & Precis Engn D-07745 Jena Germany

ISBN: (纸本)0819463671

Projection systems comprising micromechanical. scanning mirrors are a promising approach for information display of any kind. If combined with advanced laser diodes as light sources, ultra-compact projection heads can be realized, as it will be shown in this contribution. Besides the laser, key component of the system is a special MEMS device, a two-dimensional resonant micro scanning mirror. The laser beam formed by collimator optics is directed onto the micro scanning mirror. Then, the reflected beam describes a highly complicated Lissajous figure on the projection screen with flare angles of up to 20 degrees. By driving the mirror and electrically modulating the intensity of the laser beam in a synchronous manner, projection of images can be achieved. Advanced techniques that guarantee improved image quality and allow compensation of artifacts because of relative movement between projection head, screen, and human observer will be described. Based on these principles, several optoelectronic systems have been designed. A monochrome projection head that incorporates the laser diode, optics and the micro mirror could be reduced to a volume of 15mm x 7 mm x 5mm. A slightly larger head is attached to a laser unit with red, green, and blue lasers via glass optical fiber for projection of full color images and video streams. All systems have vGA (640 x 480 pixels) resolution. They operate with 8 bit color depth per pixel and 50 frames per second. These key features in combination with the miniaturized size allow their use for a broad range of applications.

关键词： image projection scanning mirror MEMS resonant scanning micro optics

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design of a thermal imaging diagnostic using 90-degree, off-axis parabolic mirrors

Design of a thermal imaging diagnostic using 90-degree, off-...

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conference on current developments in Lens design and optical engineering vII

作者： Malone, Robert M. Becker, Steven A. Dolan, Daniel H. Hacking, Richard G. Hickman, Randy J. Kaufman, Morris I. Stevens, Gerald D. Turley, William D. NSTec Los Alamos Operat 182 East Gate Dr Los Alamos NM 87544 USA NSTec North Las Vegas Operat Las Vegas NV 89193 USA Sandia Natl Labs Albuquerque NM 87185 USA NSTec Special Technol Lab Santa Barbara CA 93111 USA

ISBN: (纸本)0819463671

Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ins response time) infrared detectors. A farther complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000-5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 us. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900-1700 nm and at 1700-3000 nm, for time-resolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.

关键词： mid-IR imaging off-axis parabolic mirrors gas gun imaging IR camera pyrometry

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Low leakage current a-Si:H/a-SiC:H n-i-p photodiode with Cr/a-SiN_x front contact

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JOURNAL OF NON-CRYSTALLINE SOLIDS 2006年第9-20期352卷 1837-1840页

作者： vygranenko, Yu. Louro, P. vieira, M. Chang, J. H. Nathan, A. ISEL Dept Elect Telecommun & Comp P-1949014 Lisbon Portugal Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

This paper presents the design and fabrication process of an a-Si:H/a-SiC:H heterojunction n-i-p photodiode developed for low-level light detection applications. The critical fabrication issues associated with deposition of device-quality materials, tailoring of defects at the i-p interface, film patterning, junction passivation, and contact formation are discussed. A significant reduction of the leakage current down to similar to 10 pA/cm(2) at reverse bias of I v has been achieved by the introduction of similar to 2 nm graded and similar to 4 nm a-SiC:H buffer layers between the i- and p-layers. To preserve interface integrity, a semi-transparent Cr film with a-SiNx anti-reflection coating is used as a front contact. It is found that such contact induces lower leakage than transparent conductive oxide (TCO) contacts, which can cause a degradation of the p-i interface. A drawback of the semi-transparent metal contact is the optical loss, which can be minimized by thinning the metal layer and optimizing the anti-reflection coating. Quantum efficiency up to 52% is achieved for the optimized photodiode. (c) 2006 Elsevier B.v. All rights reserved.

关键词： silicon heterojunctions sensors plasma deposition

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Comparative analysis of λ=9μm GaAs/AIGaAs quantum cascade lasers with different injector doping

Comparative analysis of λ=9μm GaAs/AIGaAs quantum cascade ...

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7th conference of the Yugoslav Materials Research Society - Recent developments in Advanced Materials and Processes, YUCOMAT vII

作者： Indjin, D. Höfling, S. Mirčetiá, A. Jovanoviá, v.D. Radovanoviá, J. Ikoniá, Z. vukmiroviá, N. Harrison, P. Milanoviá, v. Reithmaier, J.P. Forchel, A. Institute of Microwaves and Photonics School of Electronic and Electrical Engineering University of Leeds Woodhouse Lane Leeds LS2 9JT United Kingdom Technsche Physick Universität Würzburg Am Hubland D-97074 Würzburg Germany Technische Physik Institute of Nanostructure Technologies and Analytics Universität Kassel Helnrich-Plett-Str. 40 D-34132 Kassel Germany Faculty of Electrical Engineering Bulevar kralja Aleksandra 73 11120 Belgrade Serbia Institute of Physics Pregrevica 118 11080 Belgrade Serbia

ISBN: (纸本)9780878494057

An experimental and theoretical comparative analysis of the output characteristics of λ=9μm GaAs/Al0.45Ga0.55As quantum cascade lasers based on single and double phonon resonance depopulation mechanisms were presented. The layer structures were grown with solid source molecular beam epitaxy and consist of 48 or 36 active stages embedded in a symmetrical plasmon enhanced waveguide. From the wafers, ridge waveguide lasers were fabricated by optical lithography and dry etching. The theoretical model is based on a fully non-equilibrium SchrödingerPoisson self-consistent analysis of the coupled scattering rate and single-temperature energy balance equations, taking all relevant electron-LO phonon, electron-electron and electron-ionised impurity scattering processes into account. Single phonon resonance devices exhibit clear current saturation, simultaneously with a decrease of the optical power. In the moderate doping regime, a quasi-linear dependence of both the threshold and saturation current densities on injector doping, were measured, in a very good agreement with theoretical predictions. Double phonon resonance lasers exhibit 'saturation' mechanism evident from their decrease in optical power, but without pronounced current saturation. Previously reported saturation of the 'maximal' current under higher injector doping in single phonon resonance lasers, is also observed in the double phonon resonance structure for injector sheet doping above 8×10 11cm-2.

关键词： Semiconducting gallium compounds

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InAs/InP quantum dot photonic crystal microcavities

InAs/InP quantum dot photonic crystal microcavities

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4th International conference on Semiconductor Quantum Dots (QD 2006)

作者： Frederick, Simon Dalacu, Dan Poole, Philip J. Lapointe, Jean Aers, Geof C. Williams, Robin L. Natl Res Council Canada Inst Microstruct Sci Ottawa ON K1A 0R6 Canada Univ Ottawa Dept Phys Ottawa ON K1N 6N5 Canada

We examine the optical mode structure of two-dimensional, photonic crystal microcavities based on triple missing hole defects in hexagonal symmetry, etched air-hole, suspended InP membranes. Polarisation dependent photoluminescence from InAs/InP quantum dots embedded within the cavities is used to explore mode energies and quality factors, Q, as a function of cavity design parameters. Optimised Q values are in excess of 7,500 for the modified y-dipole mode. (c) 2006 WILEY-vCH verlag GmbH & Co. KGaA, Weinheim.

关键词： III-v semiconductors

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Reduced risk of catastrophic optical mirror damage in high power tapered lasers using intra-cavity diverging lens

Reduced risk of catastrophic optical mirror damage in high p...

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conference on Semiconductor Lasers and Laser Dynamics II

作者： Tee, Chyng Wen Lau, Fat Kit Zhao, Xin Penty, Richard White, Ian Calligaro, Michel Lecomte, Michel Parillaud, Olivier Michel, Nicolas Krakowski, Michel Univ Cambridge Dept Engn Trumpington St Cambridge CB2 1PZ England Alcatel Thales III V Lab F-91404 Orsay France

ISBN: (纸本)0819462403

This paper approaches the problem of catastrophic optical mirror damage from a geometrical waveguide point of view. Instead of engineering the characteristics of the semiconductor material at the facet of the laser using quantum-well intermixing or other sophisticated wafer growth technique, a simple intra-cavity diverging lens concept is proposed and demonstrated to be capable of effectively expanding the lateral optical mode in order to counter the effect of SHB and thermal lensing effect, thereby reducing the risk of COMD. The Gaussian output beam profile is maintained throughout the whole of the current range tested, showing that expanding the nearfield at facet using integrated lens does not compromise the brightness of the laser. A key finding in this work is that the diverging effect on an optical mode is a thoroughly scalable effect that can be engineered by varying the etch-depth of the integrated lens. Fabrication of the lens is compatible with existing laser manufacturing process flow in that it can be easily implemented either by post-processing technology or by an additional lithographical step. This opens up new possibility in device design, with the beam width along the lateral direction being a parameter that can be optimized in isolation.

关键词： high power laser high brightness laser tapered laser intra-cavity lens catastrophic optical mirror damage diffraction beam quality post-processing technology

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Modeling of avalanche photodiodes by crosslight APSYS

Modeling of avalanche photodiodes by crosslight APSYS

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conference on Infrared and Photoelectronic Imagers and Detector Devices

作者： Xiao, Y. G. Li, Z. Q. Li, Z. M. Simon Crosslight Software Inc 206-3993 Henning Dr Burnaby BC V5C 6P7 Canada

ISBN: (纸本)0819463736

Avalanche photodiodes (APDs) are being widely utilized in various application fields where a compact technology computer aided design (TCAD) kit capable for APD modeling is highly demanded. In this work, based on the advanced drift and diffusion model with commercial software, the Crosslight APSYS, avalanche photodiodes, especially the InP/InGaAs separate absorption, grading, charge and multiplication (SAGCM) APDs for high bit-rate operation have been modeled. Basic physical quantities like band diagram, optical absorption and generation are calculated. Performance characteristics such as dark- and photo-current, photoresponsivity/multiplication gain, breakdown voltage, excess noise, frequency response and bandwidth etc., are simulated. The modeling results are selectively presented, analyzed, and some of results are compared with the experimental. Device design optimization issues are further discussed with respect to the applicable features of the Crosslight APSYS within the framework of drift-diffusion theory.

关键词： avalanche multiplication InP/InGaAs SAGCM APD avalanche photodiodes photodetectors optoelectronic devices semiconductor device modeling modeling software optic fiber communication

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