Frequency bandwidth estimation of TO packaging techniques for laser modules

Two simple methods for estimating the potential modulation bandwidth of TO packaging technique are presented. The first method is based upon the comparison of the measured frequency responses of the laser diodes and the TO laser modules, and the second is from the equivalent circuit for the test fixture, the TO header, the submount and the bonding wire. It is shown that the TO packaging techniques used in the experiments can potentially achieve a frequency bandwidth of over 10.5 GHz, and the two proposed methods give similar results.

Potential frequency bandwidth estimation of TO packaging techniques for photodiode modules

Scattering parameters of photodiode chip, TO header and TO packaged module are measured, and the effects of TO packaging network on the high-frequency response of photodiode are investigated. Based on the analysis, the potential bandwidth of TO packaging techniques is estimated from the scattering parameters of the TO packaging network. Another method for estimating the potential bandwidth from the equivalent circuit for the TO packaged photodiode model is also presented. The results obtained using both methods show that the TO packaging techniques used in the experiments can potentially achieve a frequency bandwidth of 22 GHz.

Packaging materials for shrimp, fish and fish products, their properties, selection and effect of different packaging materials on their shelf life

Packaging is important not only in extending the shellife of fish and fishery products but also improving their marketability. In the recent years, significant development have taken place in the packaging industry. During the past decade in India, there is almost a packaging revolution with the availability of variety packaging materials, thus generating better packaging consciousness in other producer/manufacturing industries. But unfortunately, such realisation is not forthcoming in the fisheries sector and packaging techniques for local and export trade continues to be on traditional lines with their inherent drawbacks and limitations. Better packaging ensures improved quality and presentation of the products and ensures higher returns to the producer. Among several packaging materials used in fishery industry, ISI specifications had been formulated only for corrugated fibre board boxes for export of seafoods and froglegs. This standard was formulated before containersiation came into existance in the export of marine products. Before containerisation, the standards were stringent in view of the rough handling, transportation and storage. Two of the common defects reported in the master cartons exported from India are low mechanical strength and tendency to get wet. They are weakened by the deposits of moisture caused by temperature fluctuations during loading, unloading and other handling stages. It is necessary to rectify the above defects in packaging aquatic products and hence in the present study extensive investigations are carried out to find out the reasons for the damage of master cartons, to evolve code of practice for the packaging oi frozen shrimp for exports, development of alternative style of packaging for the shipping container, development of suitable consumer packaging materials for fish soup powder, cured dried mackeral, fish pickles in oil and frozen shrimp. For the development of suitable packaging materials, it is absolutely essential to know the properties of packaging materials, effect of different packaging materials on theirshelf life and their suitability for food contact applications.

大功率半导体激光器阵列的封装技术

半导体激光器阵列的应用已基本覆盖了整个光电子领域，成为当今光电子科学的重要技术。本文介绍了半导体激光器阵列的发展及其应用。着重阐述了半导体激光器阵列的封装技术——热沉材料的选择及其结构优化、热沉与半导体激光器阵列之间的焊接技术、半导体激光器阵列的冷却技术、与光纤的耦合技术等。

Advances in high power semiconductor diode lasers - art. no. 682402

High power semiconductor lasers have broad applications in the fields of military and industry. Recent advances in high power semiconductor lasers are reviewed mainly in two aspects: improvements of diode lasers performance and optimization of packaging architectures of diode laser bars. Factors which determine the performance of diode lasers, such as power conversion efficiency, temperature of operation, reliability, wavelength stabilization etc., result from a combination of new semiconductor materials, new diode structures, careful material processing of bars. the latest progress of today's high-power diode lasers at home and abroad is briefly discussed and typical data are presented. The packaging process is of decisive importance for the applicability of high-power diode laser bars, not only technically but also economically. The packaging techniques include the material choosing and the structure optimizing of heat-sinks, the bonding between the array and the heat-sink, the cooling and the fiber coupling, etc. The status of packaging techniques is stressed. There are basically three different diode package architectural options according to the integration grade. Since the package design is dominated by the cooling aspect,. different effective cooling techniques are promoted by different package architectures and specific demands. The benefit and utility of each package are strongly dependent upon the fundamental optoelectronic properties of the individual diode laser bars. Factors which influence these properties are outlined and comparisons of packaging approaches for these materials are made. Modularity of package for special application requirements is an important developing tendency for high power diode lasers.

Fabrication and Characterization of All-Fiber Components for Optical Access Networks

This Thesis deals with the fabrication and characterization of novel all-fiber components for access networks. All fiber components offer distinctive advantages due to low forward and backward losses, epoxy free optical path and high power handling. A novel fabrication method for monolithic 1x4 couplers, which are vital components in distributed passive optical networks, is realized. The fabrication method differs from conventional structures with a symmetric coupling profile and hence offers ultra wideband performance and easy process control. New structure for 1x4 couplers, by fusing five fibers is proposed to achieve high uniformity, which gives equivalent uniformity performance to 1x4 planar lightwave splitters, isolation in fused fiber WDM is improved with integration of long period gratings. Packaging techniques of fused couplers are analyzed for long term stability.

Reibung – ein unterschätztes Phänomen in der Verpackungslogistik

„Geiz ist geil!“ ist das Motto eines Handelshauses. Aber diese Philosophie erweist sich immer häufiger als ungeeignet, längerfristigen Erfolg zu sichern. Oftmals wird gerade aus diesem Grund wieder verstärkt auf Qualität geachtet, auf die Qualität von Produkten, auf die Qualität von Herstellungsprozessen, auf die Qualität von Logistikprozessen etc. Dieser Sinneswandel beeinflusst auch alle Verpackungsprozesse, da diese untrennbar mit der Sicherung der Produktqualität und der sicheren Abwicklung aller logistischen Prozesse verbunden ist. Neben der Forderung nach einem wirtschaftlichen Produktschutz als Kernaufgabe der Verpackung müssen jedoch auch zwingende Vorgaben – beispielsweise seitens des Gesetzgebers (z. B. im Lebensmittelbereich, in der Gefahrgutlogistik, im Straßenverkehrsrecht) – beachtet werden. Das führt u. a. dazu, dass alle verpackten Güter so geschützt sein sollten, dass sie den Belastungen im Transportprozess, aber auch den Belastungen aufgrund von Ladungs- und Ladeeinheitensicherungsmaßnahmen standhalten können. Da sich jedoch nicht alle Ladegüter oder Packstücke beliebig für form- oder kraftschlüssige Sicherungsmaßnahmen eignen, sollte bei der Auslegung von Verpackungsmaßnahmen insbesondere der hilfreichen Wirkung von Reibungskräften zur Reduzierung zusätzlicher Sicherungsmaßnahmen Aufmerksamkeit gewidmet werden.

Reibung – ein unterschätztes Phänomen in der Verpackungslogistik

„Geiz ist geil!“ ist das Motto eines Handelshauses. Aber diese Philosophie erweist sich immer häufiger als ungeeignet, längerfristigen Erfolg zu sichern. Oftmals wird gerade aus diesem Grund wieder verstärkt auf Qualität geachtet, auf die Qualität von Produkten, auf die Qualität von Herstellungsprozessen, auf die Qualität von Logistikprozessen etc. Dieser Sinneswandel beeinflusst auch alle Verpackungsprozesse, da diese untrennbar mit der Sicherung der Produktqualität und der sicheren Abwicklung aller logistischen Prozesse verbunden ist. Neben der Forderung nach einem wirtschaftlichen Produktschutz als Kernaufgabe der Verpackung müssen jedoch auch zwingende Vorgaben – beispielsweise seitens des Gesetzgebers (z. B. im Lebensmittelbereich, in der Gefahrgutlogistik, im Straßenverkehrsrecht) – beachtet werden. Das führt u. a. dazu, dass alle verpackten Güter so geschützt sein sollten, dass sie den Belastungen im Transportprozess, aber auch den Belastungen aufgrund von Ladungs- und Ladeeinheitensicherungsmaßnahmen standhalten können. Da sich jedoch nicht alle Ladegüter oder Packstücke beliebig für form- oder kraftschlüssige Sicherungsmaßnahmen eignen, sollte bei der Auslegung von Verpackungsmaßnahmen insbesondere der hilfreichen Wirkung von Reibungskräften zur Reduzierung zusätzlicher Sicherungsmaßnahmen Aufmerksamkeit gewidmet werden.

Effect of Packaging Materials and Storage on Major Volatile Compounds in Three Australian Native Herbs

Lemon myrtle, anise myrtle, and Tasmanian pepper leaf are commercial Australian native herbs with a high volatile or essential oil content. Packaging of the herbs in high- or low-density polyethylene (HDPE and LDPE) has proven to be ineffective in preventing a significant loss of volatile components on storage. This study investigates and compares the effectiveness of alternate high-barrier property packaging materials, namely, polyvinylidene chloride coated polyethylene terephthalate/casted polypropylene (PVDC coated PET/CPP) and polyethylene terephthalate/polyethylene terephthalate/aluminum foil/linear low-density polyethylene (PET/PET/Foil/LLDPE), in prevention of volatile compound loss from the three native herbs stored at ambient temperature for 6 months. Concentrations of major volatiles were monitored using gas chromatography?mass spectrometry (GC-MS) techniques. After 6 months of storage, the greatest loss of volatiles from lemon myrtle was observed in traditional LDPE packaging (87% loss) followed by storage in PVDC coated PET/CPP (58% loss) and PET/PET/Foil/LLDPE (loss of 23%). The volatile loss from anise myrtle and Tasmanian pepper leaf stored in PVDC coated PET/CPP and PET/PET/Foil/LLDPE packaging was <30%. This study clearly indicates the importance of selecting the correct packaging material to retain the quality of herbs with high volatile content.

Mechanism of RNA Translocation by a Viral Packaging Motor

Molecular motors are proteins that convert chemical energy into mechanical work. The viral packaging ATPase P4 is a hexameric molecular motor that translocates RNA into preformed viral capsids. P4 belongs to the ubiquitous class of hexameric helicases. Although its structure is known, the mechanism of RNA translocation remains elusive. Here we present a detailed kinetic study of nucleotide binding, hydrolysis, and product release by P4. We propose a stochastic-sequential cooperative model to describe the coordination of ATP hydrolysis within the hexamer. In this model the apparent cooperativity is a result of hydrolysis stimulation by ATP and RNA binding to neighboring subunits rather than cooperative nucleotide binding. Simultaneous interaction of neighboring subunits with RNA makes the otherwise random hydrolysis sequential and processive. Further, we use hydrogen/deuterium exchange detected by high resolution mass spectrometry to visualize P4 conformational dynamics during the catalytic cycle. Concerted changes of exchange kinetics reveal a cooperative unit that dynamically links ATP binding sites and the central RNA binding channel. The cooperative unit is compatible with the structure-based model in which translocation is effected by conformational changes of a limited protein region. Deuterium labeling also discloses the transition state associated with RNA loading which proceeds via opening of the hexameric ring. Hydrogen/deuterium exchange is further used to delineate the interactions of the P4 hexamer with the viral procapsid. P4 associates with the procapsid via its C-terminal face. The interactions stabilize subunit interfaces within the hexamer. The conformation of the virus-bound hexamer is more stable than the hexamer in solution, which is prone to spontaneous ring openings. We propose that the stabilization within the viral capsid increases the packaging processivity and confers selectivity during RNA loading. Finally, we use single molecule techniques to characterize P4 translocation along RNA. While the P4 hexamer encloses RNA topologically within the central channel, it diffuses randomly along the RNA. In the presence of ATP, unidirectional net movement is discernible in addition to the stochastic motion. The diffusion is hindered by activation energy barriers that depend on the nucleotide binding state. The results suggest that P4 employs an electrostatic clutch instead of cycling through stable, discrete, RNA binding states during translocation. Conformational changes coupled to ATP hydrolysis modify the electrostatic potential inside the central channel, which in turn biases RNA motion in one direction. Implications of the P4 model for other hexameric molecular motors are discussed.

Electro-magnetically Actuated Minute Polymer Pump Fabricated using Packaging Technology

Design, fabrication and preliminary testing of a flat pump with millimetre thickness are described in this paper. The pump is entirely made of polymer materials barring the magnet and copper coils used for electromagnetic actuation. The fabrication is carried out using widely available microelectronic packaging machinery and techniques. Therefore, the fabrication of the pump is straightforward and inexpensive. Two types of prototypes are designed and built. One consists of copper coils that are etched on an epoxy plate and the other has wound insulated wire of 90 mu m diameter to serve as a coil. The overall size of the first pump is 25 mm x 25 mm x 3.6 mm including the 3.1 mm-thick NdFeB magnet of diameter 12 mm. It consists of a pump chamber of 20 mm x 20 mm x 0.8 mm with copper coils etched from a copper-clad epoxy plate using dry-film lithography and milled using a CNC milling machine, two passive valves and the pump-diaphragm made of Kapton film of 0.089 mm thickness. The second pump has an overall size of 35 mm x 35 mm x 4.4 mm including the magnet and the windings. A breadboard circuit and DC power supply are used to test the pump by applying an alternating square-wave voltage pulse. A water slug in a tube attached to the inlet is used to observe and measure the air-flow induced by the pump against atmospheric pressure. The maximum flow rate was found to be 15 ml/min for a voltage of 2.5 V and a current of 19 mA at 68 Hz.

Methods for characterization of packaging parasitics of semiconductor lasers

Two novel methods for analyzing the parasitics of packaging networks are proposed based on the relations between the scattering parameters of a semiconductor laser before and after packaging, and the experiments are designed and performed using our methods. It is found that the analysis results of the two methods are in good agreement with the measurements. Either of the two methods can provide an alternative approach for characterizing the packaging parasitics for semiconductor lasers, and both are convenient due to the developed measurement techniques. (c) 2005 Wiley Periodicals, Inc.