An innovative small planar packaging(SPP)system is described that can be combined with card-on-board(COB)packaging in high-speed asynchronous transfer mode switching systems with throughput of over 40-Gb/s. The SPP system provides high I/O pin count density and high packaging density, combining the advantages of both planar packaging used in computer systems and COB packaging used in telecommunication systems. Using a newly developed quasi-coaxial zero-insertion-force connector, point-to-point 311 Mb/s of 8-bit parallel signal transmission is achieved in an arbitrary location on the SPP systems shelf. Also about 5400 I/O connections in the region of the planar packaging system are made, thus the SPP system effectively eliminates the I/O pin count limitation. Furthermore, the heat flux management capability of the SPP system is five times higher than of conventional COB packaging because of its air flow control structure. An SPP system can easily enlarge the switch throughput and it will be useful for future high-speed, high-throughput ATM switching systems.

We have studied the basic optical and physical characteristics of polymeric optical waveguide films with S-shaped waveguides and 45 mirrors applied as multimode optical interconnection components. The core and cladding of the waveguide films were made of deuterated-polymethylmethacrylate (d-PMMA) and UV-cured resin, respectively. We evaluated the insertion losses of the waveguides, the crosstalk and the 45-mirror losses in these waveguide films and demonstrated that they have low propagation loss. The shrinkage and thermal expansion of the polymeric optical waveguide films are also discussed because of the interest in improving module packaging.

A high power amplifier module has been developed for large cell base station in digital cordless system. For PHS application, this module exhibited Pout of 38 dBm with low ACP of -72 dBc (at 600 kHz offset point) and a power gain of 33 dB at a supply voltage of 9 V and a frequency range of 1890-1923 MHz. In order to realize this ultra low distortion performance, power FETs have been designed as considering high breakdown voltage and thermal stability. Power divider/combiner circuits, which have the advantages of low transmission loss and a function of controlling second harmonic, have been introduced. Moreover, a novel module package with features of low cost and good processing precision has been proposed.

This paper describes a design and application method of multiple chip module (MCM) technology into microwave applications. An X-Band transmit and receive (T/R) module that has high volume production capability is described. The MMIC chip set designed to achieve multiple functions and state of the arts performance is also described. Peak performance between 8. 5 and 10. 5 GHz includes a power output of 8 W, a noise figure of 6 dB, 23 dB of receive and transmit gains, and a 5-bit phase shifter with less than 5. 5 degree rms phase error. The MCM based module utilizes advanced packaging technique, resulting in a highly integrated and mass production capability.

Optimization of InGaAs/InAlAs multiple quantum well structures for high-speed and low-driving modulation, as well as polarization insensitivity and low chirp, was investigated as a function of well thickness and strain magnitude. As a result, very short optical pulses with 4-6 ps was obtained using a low driving-voltage (<2. 0 Vpp) electroabsorption modulator module operating at a 40-GHz large signal modulation. Small chirp operation for low insertion loss (<8 dB from fiber-to-fiber) with prebias was also demonstrated and the product of the pulse width and the spectral width was estimated to be 0. 39 for a 5 ps pulse width that is nearly transform-limited.

This paper describes advanced ATM switching system hardware that uses a high-performance and cost-effective MCM-D module as an ATM-layer function device. The MCM-D module is fabricated on a Si-substrate using the stacking RAM technique to reduce module size. The MCM has a 4-layer Si substrate, a high-performance ASIC, 8 high-speed SRAMs, and an FPGA. By using the stacking RAM technique, MCM-D module size is reduced to 50. 8 mm 50. 8 mm. This is 40% of that (100 mm 65 mm) of a double-side mounted sub-board module with conventional packaging (QFP and SOP). The MCM-D module realizes the ATM-layer functions that require a high-performance ASIC with a high-speed (access time 20 ns) and large-capacity (1 MBytes) SRAM cache. The MCM approach is quite effective in increasing memory access speed because it realizes high-density packaging. The MCM-D module is mounted on an ATM line interface circuit, and realizes 150 Mbit/s throughput ATM-layer functions (header conversion and on-line monitoring) in an ATM switching system. In addition, advanced ATM switching system hardware technologies with sub-module structure are also described. The MCM-D module is one of the sub-modules of the system. This MCM technology and sub-module technology can be applied to advanced ATM switching systems.

The paper is focused on the architectural and technological solutions that will allow the transition from small to huge capacity ATM Switching Systems. This path starts from the industrial nodes available today and will arrive at the photonic switching architecture. The progressive introduction of photonics has already started with the use of optical interconnections in ATM nodes of hundreds of Gbit/s. A balanced use of microelectronics and photonics is the correct answer to the Terabit/s switching system challenge. After presenting a modular ATM Switching System, some technological solutions like Multichip Modules and Optical Interconnections are presented in order to explain how node capacity can be expanded. Some results of the research activity on photonic Switching are finally shown in order to exploit the great attitude of this technique to obtain very high throughput nodes.

This paper explores the potential of multiwave interconnectionsoptical interconnections that employ wavelength components as multiplexable information carriersfor constructing next-generation multiprocessor systems using MCM technology. A hypercube-based multiprocessor network called the multiwave hypercube (MWHC) is proposed, where multiwave interconnections provide highly-flexible dynamic communication channels among processing elements. A performance analysis shows that the use of multiwavelength optics makes possible the reduction of network complexity on an MCM substrate, while supporting low-latency message routing.

A small-sized three-stage GaAs power module has been developed for portable digital radios using M-16QAM modulation. This module has exhibited typical P1dB of 10 W with PAE of 48% and a power gain of 35 dB at a low supply voltage of 6.5 V in 1.453-1.477 GHz band. The volume of the module is only 1.5 cc, which is one of the smallest value in 10 W class modules ever reported. In order to realize the reduced size and the high power performances simultaneously, the module has employed new power divider/combiner circuits with significant features of the reduced occupation area, the improved isolation properties and the function of second-harmonic control.

This paper describes the design and performance of optical components for in-service fiber testing and monitoring in optical subscriber loops. As the number of test fibers increases, compact and cost-effective components are becoming more important. To meet this need, we have developed a highly-dense hybrid structure for optical couplers and filters, which both play key roles in testing systems. It was realized by utilizing a polyimide-base thin film filter and a waveguide-type wavelength insensitive coupler. This component operates by combining a signal and a test light with a ratio of 80/20% and isolating the test light with a value of 50 dB. The experimental samples were successfully fabricated with an excess loss of 1 dB, a return loss of 40 dB, a plolarization dependent loss (PDL) of 0.3 dB, and good environmental and mechanical stability. We successfully applied the samples to an optical branch module (OBM), and achieved a component density twice that of a conventional module. The optical characteristics of the OBM met our target values. The results we obtained for termination cords incorporating the polyimide-base filter were also satisfactory.

To realize a low-cost WDM transceiver module based on a PLC-platform, simple, assembly techniques have been successfully developed. The formation of index marks with an accuracy of below 0.1 µm has made it possible to mount Opto-electronic devices on the silicon terrace of the PLC-platform by a passive alignment. A newly developed trench formation technique for inserting a 1.3/1.5 µm WDM dielectric filter enabled us not only to ensure a stable WDM function but also to prevent excess loss associated with the dielectric filter scheme. It is found that these two technologies are practically useful to achieve high-performance WDM transceiver module.

This paper describes packaging techniques based on a novel passive alignment technique as key techniques for module assembly. A laser diode (LD) is passively positioned by detecting a pair of alignment marks located on the LD and Si substrate. A single-mode fiber is self aligned on a Si V groove. A simple receptacle structure for the module output port is also newly designed. This structure is more suitable for the automatic assembly line as well as the module mounting process on circuit board. In this paper, an advanced module applications such as a hybrid integrated wave guide module and a surface mountable (SMT) LD module is introduced.

This paper describes the technological issues in achieving a low-cost hybrid WDM module for access network systems. The problems which should be resolved in developing a low-cost module are clarified from the viewpoint of the module assembly in mass production. A design concept for a low-cost module suitable for mass production is indicated, which simplifies the alignment between a laser diode and a waveguide, and reduces the number of the components such as lenses and mirrors. The low-cost module is achieved by employing a flip-chip bonding method with passive alignment using a spot-size converter integrated laser diode (SS-LD) and p-i-n waveguide photodiodes (WGPDs) on a planar lightwave circuit (PLC) platform. We confirm that the SS-LD and the WGPD provide high coupling efficiency with a large tolerance for passive alignment. To achieve a high-sensitivity receiver, the module is designed to employ an asymmetric PLC Y-splitter that prefers a PD responsivity to an LD output power because of the high-coupling efficiency of the LD, and to employ a bare preamplifier mounting to reduce the parasitic capacitance into a preamplifier. We also demonstrate the dynamic performance for a 50-Mb/s burst signal, such as a high sensitivity, an instantaneous AGC response, and a small APC deviation of the transceiver.

Precise direct mounting of laser diode (LD) and photodiode (PD) chips on silica planar lightwave circuits (PLCs) has been investigated for application to transceiver modules. To achieve submicron optical alignment, self-aligned index marks on the PLCs and LDs were directly detected by transmission infrared light. The repeatability of the positioning was measured to be within 0.125 µm. The output power of the resultant module was 0.2 mW at 80 mA. A waveguide-type PD was also mounted in the same way, and module sensitivity of 0.25 A/W was demonstrated.

A miniature transceiver, including highly integrated MMIC front-end, for 1.9 GHz band personal handy phone system(PHS) has been developed. The terminal, adopting direct conversion transmitter and receiver technology, consists of four high-density RF circuit modules and a digital signal processing LSI with 2.7 V power supply. The four functional modules are a power amplifier, a transmitter,a receiver, and a frequency synthesizer. Each functional module includes one IC chip and passive LCR components connected with solder bumps on module substrate. The experimental miniature PHS handset has been fabricated to verify the design concepts of the miniature transceiver. The total volume of the developed PHS terminal is 60cc, including the 12cc front-end which comprises the four RF functional circuit modules. The air interface connection with the PHS base station simulator has been confirmed.

A GaAs multilayer microwave integrated circuit(MuMIC) power amplifier with a harmonic rejection filter has been developed for 1.9-GHz digital European cordless telecommunication system. Adoption of the MuMIC structure has auccessfully ended up with Q-factor of 462 harmonic rejection filter. As a result, power-added efficiency of 62.2% and P1dB of 27 dBm have been obtained at drain supply voltage of 3.6V.

Many ATM switching modules with high performance have been proposed and analyzed. A development of a large scale ATM switching system (e.g., used as a central switch) is the key to realization of the broadband ISDN. However, the dimension of ATM switching ICs is limited by the technological and physical constraints on VLSI. A multistage switching configuration is one of the promising configurations for a large scale ATM switch. In this paper, we treat a 3-stage switching configuration with no internal bufferes; i.e., bufferless switches are employed at the first and second stages, and output buffered switches at the third stage. A short-term cell loss probability is analyzed in order to examine the influence of bursty traffic on performance of the bufferless switch used at the first two stages. Furthermore, we propose a 4-stage switching configuration with traffic distributors added at the first stage. This switch provides more paths between a pair of input and output ports than the 3-stage switching configuration mentioned above. A few schemes to distribute cells are compared. It is shown that the distributor successfully reduces the deterioration of cell loss probability due to bursty traffic by splitting incoming cells into several switching modules.

A high efficiency and low voltage operation GaAs power amplifier module has been developed for the application to 1.5 GHz Japanese digital cellular phones. This paper summarizes the design method to increase efficiency and to reduce adjacent channel leakage power. Operated at a low drain bias voltage of 4.6 V, the power amplifier module delivers an output power of 1.5 W with 46% power-added efficiency and -52 dBs adjacent channel leakage power.

A 1.5 GHz band Si power MOS amplifier module with 50% total efficiency, 1 W output power and 30 dB power gain has been developed for front-end transmitter of digital cellular telephones. A combination of a highly efficient power MOSFET for the output stage and an integrated two stage MOS amplifier for the driver with an impedance matching circuit minimizing the length of striplines made it possible to achieve high total efficiency, high power gain, and smaller size of the amplifier module.

This paper describes an innovative heat-pipe cooling technology for asynchronous transfer mode (ATM) switching multichip modules (MCMs) operating with a throughput of 40 Gb/s. Although high-speed ATM link-wires are connected at the top surface of the MCMs, there is no room to cool the MCM by forced air convection, because power and the system clock signal are supplied by connectors on the rear and periphery of the MCM. We therefore chose to attach a cold-plate to the back of each MCM. The condenser part of the heat pipe, which is mounted behind the power supply printed circuit board, is cooled by low-velocity forced air. Total power dissipation is about 30 watts per MCM. With a 2 m/s foreced airflow, the sub-switching-element module (four MCMs) operates at a throughput of 80 Gb/s with a maximum junction temperature of less than 85. Measured thermal resistance between the switch LSI junction and air is about 6/W. This heat-pipe cooling system has a small system footprint, compact hardware, and good cooling capacity.