Over the last several years, it has become widely recognized that electromagnetic interlerence (EMI), electromagnetic pulse (EMP), high intensity radio frequency (HIRF), and new threats, such as directed-energy weapons, can jeopardize the flight safety of vehicles with Fly-By-Wire (FBW) systems, unless adequate shielding precautions are taken.

An overview of the field of reconfigurable optical interconnection is presented. Recent breakthrough in the elimination of fan-out energy loss using photorefractive holograms is discussed. Novel concepts using photorefractive crystal fibers for mode conversion and energy-efficient fan-in are presented and discussed.

The concept of integrated modular avionics for integrated flight and vehicle management system takes into account system decomposition modularity, function availability and fault tolerance. The system cornprises a number of modules which provide the computing resources and I/O interfaces for all applications. Interconnect architectures provide the intermodule communication and data transfer. The multi-port optoelectronic switch and associated multistage cube network architecture define a possible next step evolution beyond the current interconnect concepts. This paper presents a performance analysis of a serial multistage cube network architecture.

Device concepts for two—dimensional phased—array optics are formulated. Dielectric waveguide optics and electro—optical organic materials can be used to make multiple layers of electro-optically controlled channel waveguides and artificial prisms. Combining element scanning, array scanning, and nonuniform spacing of elements yield devices with increased resolution and reduced side—lobes. These techniques permit the fabrication of two-dimensional phase spatial-light-modulators which are applicable to two—dimensional beam scanning, wavefront shaping, dynamic lenses, and sensors.

Microoptic technology offers a possibility to solve the problems that are associated with conventional opto-mechanics. These are large size, high cost, difficult alignment and sensitivity to mechanical and thermal influences. In order to overcome these problems, the concept of "planar optics" has been suggested where microoptic components are integrated on a single substrate using a two-dimensional layout. The integration of device chips on the optical component substrate is achieved by hybrid techniques such as flip-chip bonding. An array of gallium arsenide surface-emitting microlasers integrated with a planar optical imaging system is reported. We discuss fabrication issues concerning the bonding and applications of such a hybrid structure for free-space optical interconnects.

An optical interconnect has been designed for the Touchstone supercomputer program. The objective of the system is to demonstrate scalability of the Touchstone 2-D interconnect mesh and enhance system performance. The name of the optical interconnect system is the Fiber Optic Mesh Extender (FOME). The goal of this work to to demonstrate that fiber optics can provide physical scalability in parallel supercomputing. Two ASICs were designed to control the fiber optic transmitter and receiver now under development at Honeywell's Microswitch division. This paper describes the FOME design including system architecture, planned implementation, and the resulting VHDL behavioral description.

Differential current efficiencies of 8% have been achieved in free-space optical interconnections between 3-GHz transmitter and 1.5-GHz receiver modules on opposite boards without the use of micropositioners.

The technology and system applications of high speed OEIC transmitters are discussed in this paper. By integrating .DFB lasers with lnGaAs/InAIAs MODFETs, transmitters of 10 Gb/s and wavelength spacings less than 1 nm are fabricated. The problems of crosstalk in OEIC transmitter arrays are also investigated.

The design, fabrication, and testing of a new monolithic transmitter for fiber optic interconnects is described. The transmitter is comprised of a surface-emitting AlGaAs/GaAs light-emitting diode (LED) integrated with a bipolar transistor driver circuit configured as a differential-pair current switch. Two approaches are being are being pursued: 1. the LED is integrated with a silicon-based bipolar transistor driver circuit using a novel heteroepitaxy process based on a combined chemical-vapor deposition Iliquid-phase epitaxy technique, and 2. the LED is integrated with a GaAs-based bipolar transistor driver circuit using selective liquid-phase epitaxy and diffusion processes. Transmitter components have demonstrated sub-nanosecond rise-times.

Recent progress on vertical cavity surface emitting lasers has spurred interest in them for a wide variety of applications. In this paper, we describe several schemes for achieving the addressing and control of vertical cavity laser arrays required for all applications. Vertical cavity surface emitting laser array design, fabrication, performance and uniformity are discussed. In addition, we report on the first integration of these devices with Si CMOS circuitry. Experimental measurements of perfonnance up to 622 Mbit/s of vertical cavity laser/Si driver circuits are presented.

Monolithic in—plane surface emitting laser diode arrays with 45° micromirrors offer great promise for both coherent and incoherent applications. This paper describes several such laser diode structures, summarizes the fabrication and packaging of monolithic devices of this type, and presents results for single emitters and 2—dimensional monolithic laser diode arrays.

A microchannel heat sink design, with alternating directions of coolant flow in adjacent channels, yields improved uniformity in thermal resistance. A thermal resistance of 0.1 1°C cm2/W was demonstrated for a heated area < 2 cm2. With this design, comparable performance is feasible in channels up to 10 cm long with spatial variation in the resistance <6%.

Silicon has been investigated as a platform for hybrid integration of optoelectronic, electronic, and optical components in multifiber systems. Mechanical alignment features fabricated on the surface of a silicon chip have been used to passively align the active regions of an individually addressable InGaAsPIInP laser array to four single-mode fibers. Optical coupling efficiencies have been achieved that are comparable to values obtained using the conventional technique of active fiber manipulation. Efforts are under way to fabricate hybrid transmitter arrays by the addition of GaAs electronic integrated circuits. This integration approach, which is termed silicon waferboard, has the potential to offer a compact, low-cost integration/packaging technology that can be applied to fiber-rich optical systems.

An experimental study of a prototype optically-pumped distributed-feedback resonant-periodic- gain vertical-cavity surface-emitting laser (DFB-RPG YCSEL) is reported. Both cw and pulsed conditions are investigated. The results obtained on bare wafer samples without any heat sink indicate that very high output power should be possible. Thermally limited cw output power of 6.7 mW cw was obtained with 10-?m diameter of the pumping beam. Under pulsed conditions, the output power of 8.5 W over 7 ns pulsewidth with power conversion efficiency of 10.5% was achieved. To our best knowledge, this is the highest peak power density ever reported for any semiconductor laser.

This paper reviews the recent progress in researching a planar receiver OEIC technology utilizing InGaAs MSM photodetectors and InAlAs/InGaAs HEMT amplifiers. The epitaxial materials have been grown by the low-pressure OMCVD technique on patterned InP substrates. This planar integration process has been used to address a number of different system needs. These include a balanced dual detector receiver for coherent detection, a trans-impedance amplifier receiver with a planar detector and waveguide integrated detector for direct detection, and a electronically-switched fourchannel receiver for wavelength-division-multiplexing based lightwave systems. This MSM-HEMT OEIC technology represents a major advance towards achieving high-performance and low-cost components for long-wavelength lightwave systems.

InGaAs based balanced pin-JEET front-ends have been fabricated, using a single step MBE growth and a diffused gate technology. High responsivity photodiodes were obtained by the use of an A1GaInAS window layer, and a good balance in pin characteristics was obtained. The JEET structure incorporates a two doping level channel. Input noise density of the front-ends was measured to be below 15 pAiÖHz up to 1 GHz, togetherwith a common mode noise rejection below -35dB.

The success andwidespreaduse offiberoptic technology in highvolume applications such as telecommunications and computer interconnects is largely dependent upon the availability oflow-cost optoelectronic subsystems. Typical requirements in the case of local loop telecommunications are several parallel optical channels consisting of both receivers and transmitters performing at speeds of 150 to 600 Mb/s. We describe in this paper the fabrication of a four-channel receiver making use of a hybrid integration approach on a silicon substrate. The performance of a receiver channel as well as its components, an InGaAs metal-semiconductormetal photodetector aligned to a single-mode fiber and connected to a GaAs transimpedance amplifier, will be detailed. In addition, we discuss the integration of metal-insulator-metal (MIM) decoupling capacitors into the silicon substrate design.

Wide bandwidth InGaAs/InP transimpedance optical receivers have been fabricated on 2" diameter InP substrates. Single channel receivers exhibited -3dB bandwidths of 2.2 to 2.5 GHz and an inferred optical sensitivity of -24 dBm at 4 Gbit/s for 10-9 BER. Balanced dual-detector receivers for coherent systems application showed a bandwidth of 2.3 GHz and average noise current of less than 16.8 pA/ÖHz. Common-mode signal rejection of better than 30 dB has been measured.

Novel processing techniques currently being developed for the fabrication of optoelectronic devices will be described, including fabrication of low threshold lasers using in-situ-monitored reactive ion etching, the use of impurity-induced-disordering to form high-performance lasers with self-aligned Si/Zn-diffused junctions, and the fabrication of in-plane surface-emitting lasers with 45° etched facets. Application to the monolithic integration of optoelectronic devices will be discussed.

The influence of processing on the design of optical devices and optoelectronic integrated circuits is discussed. Process compatibility of devices used as the basis of a complete optoelectronic integrated circuit will be discussed along with some potential optoelectronic integrated circuits employing only phase modulators and couplers. Specific examples of the application of reactive-ion-beam etching in the formation of passive optical waveguide phase modulators, optical interconnects, turning mirrors, and output couplers in GaAs/AlGaAs are given.

Current investigations of material issues in mass-transport fabrication are reviewed. Evaporation loss and resulting surface roughness have been identified and simple techniques developed for effective prevention. Photoluminescence intensity degradation and improvement were observed under different experimental conditions. Evidence of defect generation associated with high transport rate has also been observed. Extension of mass transport to GaAs-based heterostructure lasers showed considerable promise for advanced integrated siructures with high performance and improved reliability.

The discovery of the phenomenon of impurity induced layer disordering (IILD) has enabled novel device geometries to be applied to the task of patterning heterostructure layers for the realization of high performance optoelectronic devices. In this paper we will review progress in the various ways of implementing and controlling the IILD process, and discuss several of the potentially important device concepts for optoelectronic integration that are enabled by this technology.

Applications for high-speed fiber optic networks in military aircraft are beginning to appear and are envisioned to increase on next-generation aircraft. Current-generation JIAWG-class vehicles, such as the RAH-66 helicopter and the YF-22 fighter, are based roughly on the PAVE PILLAR avionics architecture of the l980s and wiil employ fiber optics to carry information between avionics sensor suites and mission computers via point-to-point or circuit switched networks. Data throughput requirements for these networks could reach 1 Gbps. Aircraft produced in the early part of the next century may be based on the PAVE PACE architecture now under development. With the projected increases in avionics sensor capability, information processing requirements, and cockpit display resolution, the high speed networks that interconnect these avionics subsystems may need to operate at multi-Gbps data rates. In this paper we discuss some of the basic issues involved with designing fiber optic networks for military aircraft, followed by a description of a fiber optic transmitter and receiver that we have developed for sensor and video data distribution applications in the 1 to 3 0bps range.

A GaAs/GaAlAsintegrated optoelectronic transmitter has been developed for wideband operation at 1 to4 GHz. This transmitter combines a GaAS/GaA1AS single-quantum-well (SQW) ridge-waveguide laserwith a GaAs MESFET driver circuit. The single stage driver circuit has an rf gain of 9 dB and is impedance matched to both the low resistance laserload and the 50 W microwave input by using reactive MMIC components. This design results in a nearly flat frequency response in the band of interest A combination of both laser and MMIC fabrication processes has been used to realize the transmitter in the vertically integrated MOVPE-grown material.

A versatile high speed laser structure suitable for inclusion in an an integration process is described. Performance up to 10Gbit/s has been demonstrated using a semi-insulating substrate laser. Integration with waveguide components and monitor diodes has been carried out.

Recently, the usage of long wavelength semiconductor lasers has slowly changed from R&D to manufacturing environments and from small to large volumes. The packaging of these laser diodes and appropriate automations become the driving force for low cost and high volume applications. In this paper, the packaging designs and material issues for single—mode fiber systems will be discussed. Furthermore, the trends for low-cost and high volume designs will be described. There are still many open issues in the packaging areas at this time. Some of the major ones will be addressed.

A self-consistent model of a buried heterostructure semiconductor injection laser is presented which simulates the static electrical and optical properties of buried ridge and constricted mesa lasers. It includes the effects of the superposition of all lasing modes. Results have been obtained showing that high p-type doping of the cap region has a beneficial effect on leakage current and the lateral optical field, especially at high output powers, leading to increased niodulatioii bandwidth.

We report on the design and experimental characteristics of waveguide electroabsorption modulator structures realised in (In,Ga)As strain superlattice material grown by MBE. Maximum modulation depths at wavelengths near to 980 nm are obtained with 15% indium fraction. A switching ratio of nearly 2:1 was achieved with -8 V applied bias.

We report a design of a very high frequency A1GaAs/GaAs optical modulator using a dielectric loading velocity matching technique. The optical modulator is a directional coupler which is covered with a thin coating of Ta2O5 to match the velocities of the lightwave and the if modulating signal to within 2%. The optical and rf characteristics of the modulator are analyzed using the effective index and finite difference methods. The small signal 3 dB bandwidth for the modulator is predicted to exceed 45GHz and 100 GHz for biasing at the null point and in the linear region respectively, with a maximum modulation voltage of 5V at 830nm wavelength.

Design criteria for optical phase modulators in III-V semicondutors are provided. It is shown how it is possible to operate in the choice of the structure, of the material and of the doping in order to control the trade off between low driving voltage and high bandwidth in the lumped parameters configuration.

A novel type of optical bistable circuit has been developed for application in optical communications and sinal processing. The circuit uses both optical and electrical feedback to achieve bistable operation and provides genuine optical gain. The device has advantages in that it can be triggered by optical inputs over a large spectral range and minimises signal feedback to previous circuits. Initial experimental results are presented.

A comprehensive, self-consistent thermal-electrical model of etched-well GaAs/A1GaAs vertical-cavity surface-emitting lasers (VCSEL5) is utilized to study thermal properties of cw operating devices. Various configurations of doping concentration in both cladding layers are considered. It is shown that significant improvement in controlling excessive heating of VCSELs can be achieved by relatively straightforward technological means, provided thermal behavior of the device is well understood. In particular, by increasing the doping level in the P-AlGaAs layer, the active region temperature can be reduced dramatically. The N-AlGaAs doping level has a decisive influence on the homogeneity of current injection into the active region.

An attempt is made to study the diffusion coefficient of the minority carriers in A3II B2V , II—VI and IV-VI quantum confined laser by considering all types of anisotropies within the framework of K.P formation. It is found, taking Cd3P2, CdS and PpTe lasers as examples, that the diffusion constants increases with increasing electron concentration and decreasing film thickness in a step like manner respectively. The numerical values of the diffusion constants of the minority carriers are greatest for quantum wire lasers and least for quantum well lasers in all the cases. In addition, the theoretical formulation is in agreement with the experimental results as given elsewhere.