This paper describes the development of laser transmitter arrays for analog optoelectronic link applications up to 2 GHz. These modules have been developed in an attempt to utilize passive assembly and alignment operations for the purpose of reducing costs. To this end, silicon waferboard integration platforms and semiconductor laser arrays have been fabricated with special alignment features that allow passive assembly of flip-chip laser arrays to single-mode optical fiber arrays.

We describe the design of single frequency array transmitters and their application in RF-photonic systems. In addition, we present an array-based packaging technology that is based on passive-alignment with Si-waferboards.

This paper describes the packaging challenges associated with array-based transmitters and receivers used for analog fiber-optic links. The optoelectronic modules are being developed under an ARPA Analog Optoelectronic Module TRP. The paper will focus on the development of optoelectronic array modules using silicon waferboard technology for application to personal communication systems

Two new approaches are described for epi-down die bonding of diode lasers. The first approach, based on an acetic acid vapor flux, eliminates complications associated with the use of liquid flux in optoelectronic packaging. Based on this approach, InGaAsP/InP laser arrays were soldered onto silicon substrates. These laser arrays, which were passively aligned to single-mode optical fibers on the silicon substrate, had thermal impedances comparable to those obtained using conventional liquid flux. The second approach, called bridged die bonding, is proposed as a technique for reducing stress associated with epi-down bonding of diode lasers with hard solders. Bridged die bonding seeks to minimize bonding stress by avoiding contact of the laser active region with the hard solder. Thermal modeling indicates that the bridged die bonding approach, which uses a solder pattern with an air gap, can provide a thermal impedance comparable to conventional soldering techniques.<>

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.

We have demonstrated the fabrication of two structures achieved by the thin ifim transfer technique: back4lluminated InAlAsfInGaAs metal. semiconducthr-metal (MSM) detectors with buried interdigitated fingers on GaAs substrates; and long wavelength InGaAsP lasers on GaAs or Si substrates. For optoelectromc system applications, one often considers the use of a single material system for both the optical and electronic components on the chip, because it is not complicated by lattice mismatch. Compared to epitaxial growth of latticemismatched material systems, such as GaAs on Si, the thin ifim transfer technique does not result in a substantial number of misfit dislocations which can adversely affect device performance. The results we obtained demonstrate the feasibility of the thin film transfer process and point to the potential integration of OEICs and other components fabricated from a variety of materials on a common host substrate.

A technique that makes it possible to transfer semiconductor epitaxial films from a lattice-matched growth substrate to a host substrate of a different material is discussed. The transfer of epitaxial films allows materials with different lattice constants to be bonded together without generating a substantial number of defects in regions that are critical to device operation. The thin-film transfer process utilizes metallic solder as an interface between the transferred semiconductor layers and the host substrate. In this transfer process. the film is rigidly supported at all times during transfer, providing the potential for defect-free large-area films. The fabrication of InGaAsP lasers on both GaAs and Si substrates is described. Measurements of the optical characteristics of the lasers show threshold currents comparable to those of conventional lasers

Passive alignment of semiconductor lasers and singlemode fibres has been achieved for the first time using a micro-machined silicon subtrate. Mechanical alignment features fabricated on the substrate surface were used to align the active regions of an InGaAsP/InP laser array to four singlemode fibres held in V grooves. Optical coupling efficiencies have been achieved that are comparable to values obtained using the conventional technique of active fibre manipulation. The approach, called silicon waferboard, offers the potential for low-cost optoelectronic device packaging as well as a means for dense hybrid integration of optoelectronic, electronic and optical components required for multifibre, multichip systems.